Changing Perspectives on Nitrate, Nitrite and Nitric Oxide
Eben van Tonder
11 December 2022
Introduction
I’ve spent a lot of time on the historical perspectives that emerged over the last few hundred years about nitrates, nitrites and recently, nitric oxide. I took particular note of the changing attitude towards these over the last 15 years not just from a scientific perspective, but also from a public or consumer perspective. I predicted that the avalanche of scientific data that has been emerging especially since the 1980s would eventually swing public opinion as a more complete role of these species become clear in our everyday lives and as essential to our health. More than this, the health and fitness industry would become the main vector driving change away from the stereotypical negative perspectives as the overwhelming beneficial nature of these species becomes clear to sportsmen and women in particular.
Young people are willing and able to process complex sets of information much more effectively than the older generations which means that they can assimilate more complex information which has traditionally been the main obstacle in communicating a balanced perspective related to nitrite in particular. Nitrite, nitrate, and nitrosamine formation is a complex matter. People my age and older grew up with a more linear perspective on things. Something is black or white, for example, where young people are accustomed to thinking in terms of multi-dimensional worlds with complex sets of data.
This week I came across just such a progression where a brand, in this case, CircO2 took some complex sets of data, using innovative marketing techniques and positioned a product, associated with nitric oxide and nitrate, not at the young people, but at the aspirational group of middle-aged and senior citizens. When I use the word “aspirational”, I mean this in the sense that they reach back into what influences the young generation and appropriate their new way of thinking for themselves.
I am not promoting CircO2 as a product. The fact that they use marketing techniques to explain to the general public the essential and beneficial role of nitrate and nitric oxide, and by implication, nitrite also, must be commended. More than this, I propose that the meat industry must do more to aim their own marketing along these lines. There is much we can learn from CircO2 in terms of their approach. They do not shy away from complex data sets. They embraced it and worked hard to present it in a palatable way to consumers.
Of course, CircO2 may not appreciate the link with cured meats as it may distract from their central brand message. I do not propose that there is a link except for the fact that the basics that they present as inherently beneficial in their product are exactly what has been presented as the main problem with cured meats for years. Their clear proclamation of the benefits of these reactive nitrogen species will, over time, become the basis of a complete change of attitude by the consumers towards cured meats.
It is imperative that the curing industry embrace the totality of these new findings, not just in its own messaging, but also in its formulations. What I mean is that more fruit and veg hybrids with meat products must be encouraged because the overwhelming evidence is that these will dramatically improve the health status of the current meat-only formulations. Salt and fat levels must be addressed, and the new formulations must be made available to the mass market and not just the elite consumer.
Another impressive feature of their approach is that they present solid evidence for the efficacy of not only the components included in their formulation but also the complete product. What I mean is this. They test the combined results of the remedy.
With these preliminary thoughts then, let’s delve into the matter at hand.
Their Methods and Subject Matter
My first job after three years of military service was in the industrial chemical environment. Here, Mervyn Niland, the inventor of Flight Hand cleaner taught me the five great rules of sales namely Attention, Interest, Desire, Objection and Close. The manufacturers of CircO2 do a brilliant job of getting one’s attention by introducing us to Mike (70), Eddie (60) and Des who looks closer to my age than Mike or Eddie. All living the kind of active life we all dream of. This was not always the case. Each person struggled with general health until they started giving attention to the one organ in the body often ignored. The “attention” they gave it was taking CircO2.
From Attention to Interest
The marketing team of CircO2 introduce the subject matter and immediately grab your attention which very quickly changes to interest.
They introduce us to the endothelium (a fun fact that I point out to Shannon Hounsell is that “if you could spread this organ out, the cells would cover almost 2 entire football fields!”) :-). The importance of endothelium in the health of all people and older people in particular is correctly highlighted. Related to Mike, Eddie and Des, “they all improved their health by improving the function of their endothelium” using CircO2.
They then introduce us to a surprising discovery by an MIT scientist (look how credibility is introduced early in their presentation).
The attention and interest turn to desire when they list the benefits that Mike, Eddie and Des experienced namely:
✓Restored, healthy blood pressure…
✓ Supercharged energy!
✓ Waking up feeling well-rested and raring to go!
✓ Eliminating swelling in their joints…
✓ Improved memory…
✓ Restored flexibility to arteries…
✓ Improved lung function and reverse breathing difficulties…
✓ Plan a second honeymoon!
They achieved all this by improving the health of their endothelium!
Interest turns into Desire as the story of Nitric Oxide starts to unfold!
I share the link with all my friends from the high school class of ’87! The interest changes in desire! I want this!
After the surge of enthusiasm, some doubt creeps in. Am I being taken for a ride? As soon as it all sounds “too good to be true”, the MIT scientist appears back on stage with the story of his surprising discovery. The work of Robert Furchgott, a pharmacologist from New York and his groundbreaking discoveries from 1980, is introduced. It was Furchgott who discovered that “the endothelium controls your blood vessels which makes them relax and dilate when you need more blood flow. So, when the endothelium doesn’t work well, your blood flow is restricted.”
For the rest of this article, I will present my verbatim quotes from their literature with my comments in italics.
“While Furchgott was doing his research, 2 other scientists were doing research of their own. They discovered a mysterious molecule that seemed to appear out of nowhere and quickly spread throughout the body. Wherever it went, the molecule sent signals that affected the nearby cells.”
“When Furchgott found out about their research, he wondered if there was a connection with the endothelial cells. Turns out he was right! And when the 3 scientists combined their research, Furchgott’s mystery was solved! It turns out the signalling molecule was a very fragile gas called nitric oxide. Nitric oxide sends messages to the endothelium that tell it to relax and allow more blood flow. The nitric oxide discovery was so revolutionary that in 1998, it earned all 3 scientists the Nobel Prize. And it set off a massive wave of research around the world.”
Nitric oxide is essential for your health and overall well-being. It’s as important for your body as oil is for your car.
As you may know, if you stop getting the oil changed in a car, the engine will get gummed up. Eventually, it will run out of oil. And without oil, it won’t be long before your car suffers a critical engine failure.
Well, it’s the same with nitric oxide. But instead of it being an oil, it’s a gas that keeps the endothelium healthy, so your body stays fueled with oxygen and nutrient-rich blood.
And here’s something else you need to know about nitric oxide. It’s actually very fragile. It lasts only a few seconds before it disappears. So your body needs a constant new supply to keep you healthy and active. That’s why if a person is low on nitric oxide and suddenly gets more of it, they can feel the difference almost immediately.
Nitric oxide is nothing short of a health miracle maker! It’s so important that your body has 2 ways to make it.
The first way happens right in the endothelium. There’s a process that converts an amino acid called L-arginine [L-AR-jeh-neen] into nitric oxide.
But if your endothelium starts to get sluggish, the L-arginine has a harder time converting into nitric oxide. In fact, once people get past their 20s, their nitric oxide often plummets.
A study showed that most people in their 70s have lost 75% of their nitric oxide! No wonder so many people develop health symptoms and stop enjoying life.”
Why L-Arginine Supplements Usually Don’t Work
“Since the endothelium uses L-arginine to make nitric oxide, many people believe the problem is they don’t have enough L-arginine. So they think taking an L-arginine supplement will help. And you can find plenty of them on the market that promise to boost nitric oxide. But they’re usually a waste of money. Here’s why.
Studies show once the L-arginine is swallowed, your body immediately starts to break it down. By the time it’s ready to be absorbed into the bloodstream, it’s lost as much as 75% of its effectiveness.
What’s more, L-arginine isn’t well tolerated by some people. People who take it often suffer with bloating, diarrhea, nausea, and stomach pain. So researchers who study L-arginine now say people should avoid it. They don’t see any benefit in taking it and it could cause some unpleasant side effects.
Besides, you don’t need L-arginine to make nitric oxide! Because your body has a backup plan that gives you a steady stream of it.”
Your Body’s Backup Plan
“When your body has a harder time converting L-arginine to nitric oxide, it relies more on another way to make it. This one involves your diet.
You see, there are some foods that contain a certain nutrient. Your body uses the nutrient to make nitric oxide. And what’s so surprising is that it’s a nutrient people used to think was bad. That nutrient is nitrate.
That’s right… nitrate.
You may remember hearing that hotdogs are bad for you because they contain nitrates. And it’s true that eating hotdogs may be bad for you … but it’s not because of nitrates. It turns out nitrates are a vital nutrient because your body needs them to make nitric oxide.
So what healthier foods contain nitrates? Some of the best sources are beets, garlic, spinach, nuts and seeds, and dark chocolate.
Now you may already be eating some of these foods … maybe even a lot of them. Even so, you may still be low on nitric oxide.
Why? Because you need to eat a specific amount of nitrates to get the nitric oxide effect your body needs. That amount is 300mg.
We wish we could tell you exactly how many cups that would be of each of those nitrate-rich foods. But it’s difficult to know. Because the amount of nitrates in food varies dramatically depending on where and how plants are grown, how they were stored, and how they’re prepared.
For example, the nitrate level of a beet grown in one type of soil can have 50 times more nitrate than a beet grown in another type of soil!
But there’s another, even more surprising problem.”
Up to this point, the presentation is flawless. In the curing industry, we know nitric oxide as the curing molecule with broad-spectrum anti-bacterial and anti-viral properties. It is responsible for the cooked-cured colour of meat and much of the antimicrobial efficacy associated with the curing process. For many years the curing industry relied on the use of nitrate and nitrite to generate nitric oxide and it has only recently been discovered that nitric oxide is also generated through bacteria from L-Arganine. The sources for nitric oxide are therefore the same for the body as they are for the curing industry.
A well-known Spanish company produce a mixture of fruits and herbs which they propose to cure meat without nitrate and nitrite being present in them and also apart from L-Arginine. Company’s across Europe, England and Australia have bought into these claims and produce bacon and hams from them, notably one large company in the UK that proclaim that they sell bacon that was produced without any nitrate or nitrate and also without the use of bacterial fermentation from L-Arginine.
The Spanish company in effect claims to have discovered a source of nitric oxide besides nitrate, nitrate and L-Arganine. In a recent discussion with a Dutch friend about these claims, I pointed out that people are awarded the Nobel prize for the kind of discoveries alleged by the Spanish producer. There are others who also make similar claims. These companies in question operates in an environment of secrecy with clearly things to hide. It is fair to say they did not discover another source of nitric oxide! In contrast to them, the messaging by the producers of CircO2is refreshing, transparent and spot-on!
When they say that nitrate is a source of nitric oxide, what they also say by implication is that nitrite is an intermediary in the process, but I understand why they do not delve into this as it will distract them from their simple brand message. It is important for consumers to remember that and look into this.
The Common Habit That Robs You of Nitric Oxide
“Here’s that discovery we wanted to tell you about …
A scientist from MIT was researching how the body makes nitric oxide. And he found out something quite surprising.
It turns out that your body needs a special type of bacteria to start converting the nitrate in food into nitric oxide. And the bacteria live on your tongue. So the process needs to start in your mouth.
Without those bacteria, you could be eating nitrate-rich foods by the truckload, and you’d never make the nitric oxide your body needs to stay healthy. And get this …
It turns out 2 out of 3 people don’t have enough of the special bacteria! And it may surprise you to hear why.
If you take good care of your teeth, there’s a good chance you don’t have much of the special bacteria left.
That’s right. Most mouthwashes … and even fluoride toothpastes … kill the bacteria your body needs to make nitric oxide.
That’s why a person can eat a healthy diet, exercise, and still not stop the decline in nitric oxide as they age.
Luckily, you don’t have to sacrifice healthy teeth and fresh breath to boost your nitric oxide. Because the tongue bacteria discovery gave some scientists an idea.”
“The scientists were doing research at the University of Texas Health Science Center. And they discovered there’s a simple way to get your body to produce more nitric oxide. It works even if you have a sluggish endothelium.
They discovered that with the right ingredients, your body can still produce nitric oxide… provided the ingredients mix with a certain amount of the tongue bacteria. And after a lot of trial and error, the scientists discovered the winning formula. It’s a 5-ingredient combo that works like magic!
The scientists had another problem to solve. They had to figure out how to get the ingredients to mix with enough of the bacteria. That meant a pill or a drink wouldn’t work because they don’t spend time in your mouth.
So to solve the problem, they created a special lozenge. As it dissolves in your mouth, it mixes with just enough of the bacteria to get the nitric oxide process started. And the results are amazing!”
The ingredients they discuss are of interest and have been and are currently the subject of active study by me and a colleague, Richard Bosman. So, it is of great interest to continue looking at their ingredients within the context of nitrate, nitrite and nitric oxide but before we do so we must look again at the method they chose for taking their product which is actually nothing novel.
They re-discovered what has been known since antiquity. The oldest prescription that describes a similar action is the Dunhuang manuscript discovered in the Mogao Caves in the far Western region of China by a Daoist monk, Wang Yuanlu on 25 June 1900.The mix of religious and secular documents dates from the 5th to the early 11th centuries. One text is of particular interest to us, referred to as the Dunhuang Medical Text. The text is attributed to the famous Daoist alchemist and physician Toa Hongjing (CE 456 – 536).” (Cullen, C, Lo, V.; 2005) There is evidence that it relies on earlier traditions from the Han and Sui Dynasties. “The original was decorated with images of the Three Daoist Lords and the Twelve Constellations, indicating links with Doist traditions. In translation, it reads as follows:
From Cullen, C, Lo, V.; 2005
“The symptoms described by the patient, as described in the Dunhuang manuscript, suggests an advanced case of cardiovascular distress. The colour of the fingernails (cyanosis) indicates ischaemia (lack of oxygen in the tissue) due to restricted blood flow. Cold hands and feet are additional symptoms of this condition. Also, acute pain suggests that the patient may be suffering from severe angina, i.e. restricted blood flow due to the narrowing of the cardiac arteries.” (Cullen, C, Lo, V.; 2005)
“Modern treatment for angina is glyceryl trinitrate or isosorbide dinitrate. So, at first glance, there seems to be a similarity in treatment. All three remedies contain the all-important nitrate. Salpeter is, however, an inorganic compound that exists as a positively charged potassium cation (K+) and a negatively charged nitrate anion (NO3-). Concerning organic nitrate, such as glyceryl trinitrate, there is a covalent bond or a molecular bond between the nitrate moieties (NO3) where they share electron pairs which form the bond with the rest of the molecule (CH2). Where glyceryl trinitrate relaxes the muscle lining of the artery to relax, enlarging the vessel and so allowing more blood flow, saltpetre by itself will have no effect on the treatment of angina.(Cullen, C, Lo, V.; 2005)
This is, however, not the full story. The remarkable feature of the Dunhuang text is that the combination of the use of saltpetre (which is nitrate), not on its own, but when applied according to the dictates of the text, becomes a remedy for exactly the condition described. “The thing about glyceryl trinitrate is that this too, in itself, is not a vasodilator (relaxing of the arterial lining). It is transformed, probably in the arterial wall, into nitric oxide, a chemical species which is the vasodilator. Under very special circumstances, exactly as detailed in the Dunhuang text, <beginning with microbial conversion of nitrate to nitrite by bacteria in the tongue,> the nitrate ion from saltpetre also converts to exactly the same species which is the vasodilator (nitric oxide). Despite the fact that glyceryl trinitrate has been in use for over a hundred years, the identity of this species has only been discovered in 1987.” (Cullen, C, Lo, V.; 2005) The discovery is what the producers of CircO2 have been describing and the reason for the efficacy of the Dunhuang text related to saltpetre is exactly the reason why CircO2, replete with beetroot, a rich source of nitrate is effective to produce nitric oxide in the body and their method of changing nitrate into the species which can achieve the production of nitric oxide is what is done with nitrate in CircO2.
The efficacy of these methods of taking the compounds describes rests on the reduction of nitrate to nitrite in the mouth. As I stated before, the owners of CircO2 do not discuss this, but for the meat curing industry, it is important to note that this reaction is the key issue here. The conversion of nitrate to nitrite by bacteria that was known since antiquity (even though they could not have understood the exact mechanism) turns out to be a very important feature of human existence and health, generally.
Bryan (2011) points to this key relationship between nitrate and nitrite with nitric oxide when he writes that “from research performed over the past decade, it is now apparent that nitrate and nitrite are physiologically recycled in blood and tissues to form Nitric Oxide and other bioactive nitrogen oxides.” One of the important sources of nitrite is “Nitrite is also derived from the reduction of salivary nitrate by bacteria in the mouth and in our stomachs. This is the basis for the efficacy of both Circo2 as well as the remedy prescribed in the Dunhuang manuscript. Bryan expands on this, that another source of nitrite is “from dietary sources such as meat, vegetables and drinking water.” The meat he refers to is probably fresh meat, but we know cured meat is an extremely good source of dietary nitrite. In order for nitrate to become effective in our metabolism, it must first be changed into nitrite, and because mammals lack specific and effective enzymes to do this conversion it is mainly carried out by bacteria in the mouth and stomach or by bacteria that are found on our skin. I deal with this in detail in a chapter in my book on meat curing. The chapter is called The Curing Molecule.
“Once in the mouth, . . . bacteria change nitrate to nitrite. This change requires the presence of these bacteria — suggesting a functional symbiosis relationship — as mammalian cells cannot effectively metabolize nitrate. “When saliva enters the acidic stomach (1 — 1.5 l/day), much of the nitrite is rapidly converted to nitrous acid, which decomposes further to form Nitric Oxide and other nitrogen oxides. This human nitrogen cycle is illustrated below. Once nitrite is absorbed and circulated, it is taken up by peripheral tissues and can be stored in cells.” Bryan (2011)
The image above if from Bryan (2011).
Now back to the ingredients in CircO2.
The Weed That Keeps Your Blood Flowing Like Niagara Falls!
The first ingredient they mention is hawthorn. “It’s been used in Asia since the 1st century to help people with heart, circulatory, and respiratory troubles. And modern scientific research confirms that hawthorn has a remarkable ability to protect endothelial cells from damage.
As you saw earlier, when your endothelium is damaged, your blood flow is restricted. This starves your cells of fresh oxygen and nutrients … including your endothelial cells. This shortens their life and starts a vicious cycle.
As your endothelial cells die, your blood flow becomes more restricted, which causes more endothelial cells to die. And around it goes.
Hawthorn breaks the vicious cycle … and throws it into reverse! It does it by protecting the endothelial cells from damage.
In fact, researchers tested hawthorn extract against several other powerful medicinal herbs. And hawthorn gave endothelial cells 6 times more protection from damage! That means they live longer. That helps repair your endothelium, which improves your blood flow and brings your starving cells back to life.”
The next two ingredients are beetroot and L-Citrulline.
The 2 Most Powerful Nitric Oxide Boosters
“The first one is beet root powder. Beet root powder is loaded with health benefits! It’s a powerful antioxidant … it fights inflammation … it improves brain function … and it’s an amazing source of nitrates. That makes it a nitric oxide-producing powerhouse! In fact, a study showed drinking beet root juice almost doubles your nitric oxide!
In the study, researchers timed a group of people riding a stationary bike until they were too exhausted to continue. They also measured their nitric oxide levels, how much oxygen the participants had in their blood, and how much got into their muscles. Then they split them into 2 groups.
One group got beet root juice to drink every day for 6 days. The other group got a sham drink that tasted like beet root juice but didn’t have any nitrates in it.
At the end of the study, the people came back and were tested again. And the researchers were astonished by what they saw!
The people drinking beetroot juice increased their nitric oxide by 96%! That’s almost double! But not only that…
Instead of gasping for air, they needed less oxygen to pedal … and they could pedal longer, too. But the people who got the fake drink didn’t see any benefit whatsoever.
Beetroot is one of the best nitric oxide-boosters you can find.”
Beetroot juice is replete with both nitrate and nitrite. The fact that the tablet is held in your mouth means that nitrate-reducing bacteria change nitrate into nitrite so that even more nitrite is swallowed. It completely obliterates the tight link that popular science presented for years that nitrite = cancer. The fact that CircO2 not only include it in their remedy but even prescribe the action of holding it in your mouth for a while before swallowing it is a stunning reversal of the old and outdated view of nitrites.
Their formula “also contains an ingredient that gets around the L-arginine problem. And it helps your endothelium make more nitric oxide, too.”
Helps Your Endothelium Make More!
As we mentioned earlier, taking L-arginine supplements doesn’t do much to help your body make nitric oxide. And besides, there’s something even better you can do.
You can get your body to make more L-arginine! How? With something called L-citrulline [L-sit-true-lean].
L-citrulline is an amino acid that your body uses to make L-arginine. And your digestive system doesn’t break L-citrulline down. L-citrulline gives you other benefits, too.
It improves concentration, increases blood flow, and reduces muscle fatigue. In fact, a study found L-citrulline can even give you more muscle power.
In this study, the researchers split people into two groups. One group took L-citrulline capsules for 7 days. The other group took capsules filled with a cornstarch placebo. After a week, both groups met with the researchers for testing.
First, the researchers tested their level of L-arginine. And they were amazed! In just 7 days, the people taking the L-citrulline had an astonishing 38% more L-arginine in their bodies!
Then both groups were tested to see how fast they could ride 4-kilometers on a stationary bike. The L-citrulline group finished faster! But the researchers had to make sure it was because of the L-citrulline. So they did the study a second time. Only they switched the capsules. So the ones who got the L-citrulline the first time got the placebo, and vice versa.
And the results from the second test confirmed it! In each case, the L-citrulline group had more L-arginine and finished the bike race faster. Not only that … the people all said when they took the L-citrulline, their muscles didn’t feel as tired. And they noticed they had more concentration.
So L-citrulline helps your body both physically and mentally. And it keeps your level of L-arginine elevated so your endothelium can make nitric oxide all day, without any side effects.
The 2 Essential Nitric Oxide Vitamins
Their remedy also contains 2 vitamins that are essential to your body’s ability to make and use nitric oxide.
Vitamin B12: Many people don’t get enough B12, or they have trouble absorbing it. B12 is important because it protects the nerve endings in your brain. People who don’t get enough of it often notice they have problems with their memory.
Not only that. Low B12 is shown to lower your nitric oxide levels too. That’s why CircO2 has 1000 mcg of B12. This helps your body to make nitric oxide, while also giving your memory a boost!
Vitamin C: You already know that vitamin C is great for supporting your immune system. Well studies show it also helps your body make nitric oxide … especially when you’re over 60.
Right around the age of 60, people’s bodies start having a hard time clearing out toxins. And toxic build-up is one of the things that wears out your endothelium. But vitamin C is shown to seek out and remove the toxins that weaken your endothelium.
The combination of these 5 powerful nitric oxide-boosting ingredients … in a delicious lozenge that melts on your tongue … makes CircO2 the best nitric oxide-booster you can find. And the results speak for themselves.
In cured meats, adding vitamin C fulfils another important function besides its value in CircO2. It is legislated in most countries on earth, that wherever nitrites are used to cure meat, vitamin C must be part of the formulation because it blocks the possible formation of nitrosamines in the human body. The link with cancer is the formation of nitrosamines the possible formation which is prevented by adding vitamin C. (Mirvish, 1975) This, the fact that vitamin C is added to all cured meats, together with the minuscule amounts of nitrites used in meat curing, considered in the comparatively massive amounts that it exists in leafy green vegetables such as beetroot and spinach, it key physiological function in the human body, the amounts swallowed every day from our saliva, all points to nitrite in cured can not possibly be the reason why some studies point to possible health concers associated with it.
The fact that a product like CircO2 exists is a testimony to the erroneous science that concluded that nitrite is to blame for any possible adverse health effects of cured meat. I appreciate how the owners of the CircO2 referred to it that hotdogs may be unhealthy, but it is not for the inclusion of nitrates (and by implication, nitrites). What is interesting is that the possible reasons why certain brands of cured meat are unhealthy are far more within the control of the processor than the use of nitrite and ultimately nitric oxide without which meat can not be cured.
Boosts Nitric Oxide in Just 20 minutes!
The point of quoting their presentation is to show that when one talks about nitrite, nitrate and nitric oxide and you ingest it through cured meat, leafy green vegetables or the formulation, CircO2, the results are almost instantaneous!
Most supplement companies rely on studies that test the individual ingredients in their supplements. But they never study how people respond to the product itself. That’s not the case with CircO2. In fact there are several studies that show how well the actual CircO2 lozenge works.
In one study, researchers gave people the lozenge to dissolve on their tongue. Then every 5 minutes, the researchers used the same process we mentioned earlier to measure the amount of nitric oxide in their body. They kept measuring them for over an hour. And the results were astonishing!
The participants’ nitric oxide levels began to rise almost immediately. In less than 20 minutes, their nitric oxide was 650% higher! And it stayed elevated, too!
In another study, researchers tested the formula on a group of people aged 42 to 79. All of them had high triglycerides.
The researchers split them into two groups. One group got a box of lozenges with the CircO2 ingredients, and the other got a placebo. They were told to let a lozenge dissolve on their tongue every morning and evening.
When the 2 groups returned 30 days later, the researchers tested their triglycerides again. The CircO2 group’s triglycerides dropped by as much as 55% … without making any other changes to their lifestyle!
But even better was how the CircO2 group felt. At the end of the study, the participants from both groups filled out a questionnaire. Many people in the CircO2 group said they:
– Felt more relaxed
– Slept better
– Had more energy
– Were less anxious
And most of them said they felt so good they wanted to continue taking the lozenge.
There’s just no denying it! You feel noticeably better when your cells are flushed with oxygen and nutrients! And it makes you healthier, too.
Nitric oxide can do more for your health and well-being than practically anything else I’ve seen. In fact, I’m shocked that the standard screening tests we get when we’re older don’t include a way to test for nitric oxide.
Having masterfully taken us through the steps of attracting our attention, piquing our interest, motivating a desire for their product to develop, and overcoming objections, they now close the deal with links to their order portal and the promise of a healthy and bright physical future.
Conclusion
For those interested to learn more about CircO2, either do an internet search or visit advancedbionutritionals. Products like these will continue to become available based on the latest research. The wellness and sports nutrition industry are far advanced in embracing the value of nitrite, nitrate and nitric oxide.
The curing industry is lagging behind in assimilating this research into its own messaging and in formulating new and improved products that embrace similar research that not only show that nitrite does not equate to cancer, and instead embraces the full spectrum of the benefits of plant components.
This is the sole focus of the work of Richar Bosmann and me. It should be a major focus for everyone!
A South African friend living in Australia sent me a message this morning about an evaluation I did about the recently launched no-nitrite bacon from Woolworths which I suspect to be similar to the Spanish company I described earlier (Evaluation of Woolworths “contain no nitrites” Bacon). He wrote, “I have read this morning an interesting article from Prof Henry Mintzberg where he was writing about Milton Friedman’s doctrines and Henry said the following: ‘When the corporation knows more than its clients do, there is room for deception. A good deal of advertising can be described as manipulative in nature, that is, designed not to inform but to affect ― to create emotional need or dependency. To the extent that this kind of advertising works ― expressly as it is designed to ― then to use Friedman’s terms, it coerces the consumer and evokes involuntary cooperation, thereby distorting consumer sovereignty.” This is exactly NOT the kind of advertising that CircO2 practices and as excited as I am by them bringing the subject matter they address into the popular mass media, I think their approach is a rebuke to a lack-lustre response by the meat industry! They certainly seek to educate with integrity and capitalise where the meat industry seems to do nothing!
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References
Bryan NS. Application of nitric oxide in drug discovery and development. Expert Opin Drug Discov. 2011 Nov;6(11):1139-54. doi: 10.1517/17460441.2011.613933. Epub 2011 Aug 25. PMID: 22646983.
Cullen, C, Lo, V.. 2005. Medieval Chinese Medicine: The Dunhuang Medical Manuscripts. Routledge Curzon.
Mirvish SS. Blocking the formation of N-nitroso compounds with ascorbic acid in vitro and in vivo. Ann N Y Acad Sci. 1975 Sep 30;258:175-80. doi: 10.1111/j.1749-6632.1975.tb29277.x. PMID: 1106296.
The importance of nitrite in our diet can hardly be overstated. These dietary sources include cured meats even though it is by no means the largest source. The challenge is to understand the factors which prevent cured meats from being seen as a superfood and address these. The presence of nitrites does not seem to be one of these!
In Part 5. Nitrite – the Misunderstood Compound we looked at the protective effects of dietary Nitrate/Nitrite on lifestyle-related diseases mainly from the work of Kobayashi (2015). We also looked at work done which shows the adverse effect of the lack of nitrites on the body. Here I list more health benefits, this time mainly from the work of Rassaf (2014).
Nitrite
By way of overview, let’s briefly list again the sources of nitrite for the human body.
– Three Sources of Nitrite
1. NO -> produced endogenously from L-arginine by NO-synthases (NOSs)
In the body, nitric oxide (NO) is oxidised to nitrite. (Rassaf, 2014)
NO rapidly reacts with oxyhaemoglobin to form methemoglobin and nitrate. (Rassaf, 2014)
On the other hand, several pathways exist in the body that provides the reduction of nitrite to NO, with haemoglobin, myoglobin, neuroglobin, cytoglobin, xanthine oxidoreductase, eNOS and mitochondrial enzymes being involved (for reviews see: van Faassen et al. 2009; Lundberg et al., 2009). The extent of contribution of the different pathways depends on the tissue, the pH, oxygen tension and redox status (Feelisch et al., 2008).
2. Nitrite reduced from nitrate
Sources for nitric oxide (NO) formation in mammals. NO is formed by the endothelial NOS (eNOS) using L-arginine as a substrate in an oxygen-dependent manner. Dietary nitrate is reduced to nitrite via commensal bacteria in the oral cavity. Nitrite can be reduced to NO in eNOS independently via deoxygenated myoglobin (Mb), haemoglobin (Hb), neuroglobin (Ng), xynthin oxidoreductase, protons, aldehyde oxidase and enzymes of the respiratory chain to bioactive NO. (figure and description by Rassaf, 2014)
3. Dietary sources
Cured meat, baked goods, beets, corn, spinach etc. are major sources of nitrite. (Rassaf, 2014)
Reference list below for nitrite dietary contributions.
Sindelar (2012), as quoted by (Kobayashi, 2015)
Hord (2009) as quoted by (Kobayashi, 2015)
Benefits of Nitrite
As I said, I now list more health benefits of nitrite.
-> Contribute to protection against UV-induced cell damage.
The presence of nitrite, but not nitrate, reduced the extent of apoptosis, or the death of cells which occurs as a normal and controlled part of an organism’s growth or development, in cultured endothelial cells during UVA-irradiation in a concentration-dependent manner by inhibiting lipid peroxidation. (Rassaf, 2014) Endothelial cells form the inner lining of a blood vessel and provide an anticoagulant barrier between the vessel wall and blood.
The protective effect described above was abolished by simultaneous administration of a NO scavenger (Suschek et al., 2003) suggesting that nitrite-derived NO may contribute to protection against UV-induced cell damage (Suschek et al., 2006). (Rassaf, 2014)
-> Protection of gastric mucosa from hazardous stress.
We look at this when we considered the work of Kobayashi (2015) but due to the importance, I mention the point again. Nitrite, generated from nitrate by oral bacteria ‘the so called enterosalivary cycle’, and then converted to NO (Benjamin et al., 1994; Lundberg et al., 1994; 2009; 2006; 2008; Kapil et al., 2010a) in the stomach was also suggested to play an important role in the protection of gastric mucosa from hazardous stress (Miyoshi et al., 2003). (Rassaf, 2014)
-> Cardiovascular Benefits
Since the rate of NO generation from nitrite depends on the reduction in oxygen and pH, nitrite could be reduced to NO in ischaemic tissue or tissue lacking oxygen and exert protective effects (for review, see van Faassen et al., 2009). Nitrite-mediated protection was independent of endothelial nitric oxide synthase (Webb et al., 2004; Duranski et al., 2005).
-> The Brain
Depending on the timing of application nitrite might not only reduce irreversible brain injury following ischaemia/reperfusion but also vasospasm following cerebral haemorrhage. (Rassaf, 2014) Ischaemia/ reperfusion refers to the paradoxical exacerbation of cellular dysfunction and death, following restoration of blood flow to previously ischaemic tissues which refers to the demand of tissue for energy, for example from oxygen, and this demand is not matched by supply moslty due to to a lack of blood flow.
-> Protection of the Liver
Nitrite exerted profound dose-dependent protective effects on cellular necrosis which refers to the loss of cell membrane integrity as a result of exposure to a noxious stimulus and apoptosis which refers to a form of programmed cell death that occurs in multicellular organisms. Nitrite has a highly significant protective effect observed at near-physiological nitrite concentrations. (Rassaf, 2014)
-> Protection of the Lungs
In a mouse model of pulmonary arterial hypertension, inhaled nebulized nitrite has been demonstrated to be a potent pulmonary vasodilator that can effectively prevent or reverse pulmonary arterial hypertension. (Rassaf, 2014)
-> Protection of the kidneys
In rats subjected to 60 min of bilateral renal ischaemia and 6 h of reperfusion sodium nitrite administered topically 1 min before reperfusion significantly attenuated renal dysfunction and injury. (Rassaf, 2014)
Renal ischemia associated with renal artery stenosis (RAS) which is the narrowing of one or more arteries that carry blood to your kidneys is the most frequent condition occurring with renin-dependent hypertension. Renovascular hypertension (RVH) results from occlusion (the blockage or closing of a blood vessel or hollow organ) of blood flow to either kidney, which stimulates renin release. Increased renin leads to a series of actions that rapidly leads to increased systemic blood pressure or hypertension or abnormally high blood pressure. (Rassaf, 2014)
Similarly, in mice subjected to bilateral renal ischaemia for 30 min and 24 h reperfusion, renal dysfunction, damage and inflammation were increased; these effects were all reduced following nitrite treatment 1 min prior to reperfusion. (Rassaf, 2014)
-> Crush syndrome and shock
Limb muscle compression and subsequent reperfusion are the causative factors in developing a crush syndrome. In rats subjected to bilateral hind limb compression for 5 h followed by reperfusion for 0 to 6 h, nitrite administration reduced the extent of rhabdomyolysis markers such as potassium, lactate dehydrogenase and creatine phosphokinase. Nitrite treatment also reduced the inflammatory activities in muscle and lung tissues, finally resulting in a dose-dependent improvement of survival rate. (Rassaf, 2014)
Similarly, in a mouse shock model induced by a lethal tumour necrosis factor challenge, nitrite treatment significantly attenuated hypothermia, mitochondrial damage, oxidative stress and dysfunction, tissue infarction and mortality. (Rassaf, 2014)
Nitrite could also provide protection against toxicity induced by Gram-negative lipopolysaccharide. (Rassaf, 2014)
Conclusion
Rassaf (2014) concluded that “taken together, the nitrate-nitrite-NO pathway appears to play a crucial role in protecting the heart, vessel, brain, kidney and lung against ischaemia/reperfusion injury. Nitrite treatment may be advantageous in well-known NO deficient states such as, for example, hyperlipidaemia. Timing and dose of nitrite application as well as the potential to convert nitrite to NO in the tissue are important to obtain a reduction in injury.
That nitrite is not a compound to be avoided at all costs is clear. It is essential to our health and dealing with the stress and strain of living life and mediating the effects of the many injuries we incur. The mass hysteria against the use of nitrites in cured meat is unfounded. The discussion about adapting our formulations to include the latest science related to diet and nutrition needs to take place as it is true for every food group in existence but lumping the meat industry into the same group as producers of cigarettes, for example, is unjustified and dangerous. A far more balanced and responsible discussion is called for and I hope that this series contributes to the discussion.
Hord, N.G.; Tang, Y.; Bryan, N.S. Food sources of nitrates and nitrites: The physiologic context for potential health benefits. Am. J. Clin. Nutr. 2009, 90, 1–10.
Kobayashi, J. (2015) NO-Rich Diet for Lifestyle-Related Diseases, Article in Nutrients, June 2015, DOI: 10.3390/nu7064911
Rassaf T, Ferdinandy P, Schulz R. Nitrite in organ protection. Br J Pharmacol. 2014 Jan;171(1):1-11. doi: 10.1111/bph.12291. PMID: 23826831; PMCID: PMC3874691.
The accusation is widespread in the media, sensation-seeking documentaries and celebrity chefs alike that nitrite, derived from ammonia, nitrate (Salpeter) or added in the form of sodium nitrite in meat curing is tantamount to poisoning consumers and inviting cancer into your lives. I am a meat curing professional. My interest in the truth about nitrites is in the first place to be certain that I am not engaged in an action where harmful products are produced. To state this slightly differently, what steps can I take to ensure the safest possible product is made available?
The issue of nitrites is complex and to develop even a rudimentary understanding of all the issues requires that we work through a lot of technical information. Despite this, the basic evaluation is simple and well within the grasp of the general public. Here I desire to share with you what I discovered about this remarkable compound!
It is part of a short series I’ve put together on the matter entitled, The Truth About Meat Curing: What the popular media do NOT want you to know! After preliminary discussions, we now place the spotlight squarely on nitrite. We discover that instead of poison, even though this is true in large dosages and under certain conditions, it is a vitally important compound for the normal functioning of our bodies. That the sources are mostly from vegetables and not cured meat, and that any possible harmful effect is removed through the simultaneous consumption of vitamins A, C, E, etc.
What I discovered is that an entirely different (and positive) world exists related to nitrites generally and dietary nitrites in particular. The evidence is clear, overwhelming and available to anybody with an honest interest in the matter that nitrites are beneficial to human health and essential for the optimal functioning of our bodies. We will discover that there is a seemingly unresolved issue in that while nitrites, in balanced concentrations, have overwhelmingly beneficial results in the human body (may I even call it essential?!), there is seemingly contradictory information which shows that nitrites are involved, under certain conditions in the generation of N-Nitrosamines which can be cancer-causing. Parallel to this is the indication of many studies that there seems to be a relationship between the consumption of cured meats and cancer and even though the exact reason has not been elucidated, it begs the question as to possible reasons for this. How do we deal with this seemingly contradictory information, that n-nitrosamines which are the obvious culprit for any possible link between cured meat and cancer on the one hand come from nitrites and on the other hand, nitrites play an vital part in our general health and the resolution of many common diseases and ailments? Can it be that nitrosamines are not the culprit of what seems to be a link between cancer and cured meat? Can it be that lifestyle or general nutritional habits alter the nature of an important chemical in our bodies from beneficial to harmful and if this is the case, what are those factors? Is it fair to label bacon as possibly cancer-causing? When it comes to the full array of reactive nitrogen species of which nitrite is a part, is it possible to have the one without the other, especially in light of the fact that the curing molecule is nitric oxide, also one of the reactive nitrogen species? Is the statement that curing was done with no nitrite even a sensical one in light of the oxidation of nitric oxide to nitrite and nitrite to nitrate in the curing environment? It begs the question if no nitrite curing which has been the goal of meat scientists for so many years even valid question to ask or is this something that will sell products without any real benefit to the consumer as far as the removal of the real risk of n-nitrosamine formation. This is an extremely timely question as we stand at the dawn of a time when no-nitrite curing will become a reality across the world. The emphasis is about to squarely shift to nitric oxide and in light of this future trend we have to ask, can nitric oxide contribute to nitrosamine formation as is the case with nitrites which would mean that removing nitrites from the curing system has no real benefit as far as nitrosamine formation is concerned.
We have to continue the questioning. If ingesting dietary nitrite has overwhelmingly positive effects on human physiology, should nitrite curing not rather be encouraged and embraced and should ham and bacon not be seen as a superfood instead of something to be avoided? I ask another question which is the focus of my own work and that of a small band of like-minded food professionals and scientists – how do we turn ham, bacon and the cured meats we love into superfoods in such a decisive manner that there can be no argument from any quarter about this status!? These are all valid questions and despite the mammoth task ahead, I will do my best to interact with all these questions in this document. Where I fail, please point it out to me so that I can improve on the document and evolve in my thinking, but please, do it from a position of constructive interaction and partnering with me in seeking the truth!
I will try and deal as honestly as a layman can with these complex questions, believing that I have a sacred responsibility to the consumer to do exactly this and if the evidence points away from what I would like it to say, that I should have the integrity follow the lead of the evidence. My ultimate goal is therefore the TRUTH and not to generate “likes” on social media posts. Anybody with a meaningful contribution or who wants to correct me on any point can contact me at ebenvt@gmail.com or WhatsApp me at +27 71 545 3029.
History of Nitric Oxide and the Close Link between Nitrate, Nitrite and Nitric Oxide.
Nitric oxide (NO) was discovered in 1772. Nitroglycerine (NG), a vasodilator acting via NO production, was synthesized in 1847. The effect of nitroglycerine was studied on healthy volunteers by Constantin Hering in 1849 and it was proven to cause headaches. Later in 1878, nitroglycerine was used by William Murrell for the first time to treat angina. Towards the end of the 19th century, nitroglycerine was established as a remedy for relief of anginal pain.” (Ghasemi, 2011) Angina is a type of chest pain caused by reduced blood flow to the heart. In 1916, Mitchell et al. suggested that body tissues can also produce nitrate and Richard Bodo in 1928 showed a dose-dependent increase of coronary flow in response to sodium nitrite administration. In the 1970s, it was shown that nitrite-containing compounds stimulate guanylate cyclase,” which is an enzyme that converts guanosine triphosphate (GTP) to cyclic guanosine monophosphate (cGMP) and pyrophosphate. An increase of cyclic guanosine monophosphate (cGMP), also caused by the intake of nitrite containing compounds cause vascular relaxation and it is presumed that cGMP activation may occur via the formation of NO. (Ghasemi, 2011)
In 1980, Furchgott and Zawadzki showed that endothelial cells are required for acetylcholine-induced relaxation of the vascular bed which refers to the vascular system or a part thereof, through the endothelium-derived relaxing factor. Even though they could not initially pinpoint what caused the relaxation of the endothelium, scientists knew that such a relaxing factor existed and the race was on to identify it. The endothelium is the thin membrane that lines the inside of the heart and blood vessels. The breakthrough came in 1987 when it was shown that endothelium-derived relaxing factor and NO are the same or almost the same thing. Nitric oxide was the agent responsible for relaxing the endothelium. (Ghasemi, 2011)
In 1992, NO was proclaimed as the molecule of the year and in 1999, Furchgott, Ignarro, and Murad were awarded the Nobel Prize in Physiology or Medicine for studies in the NO field. Due to the proven roles played by NO physiologically and pathologically, research on NO was increased rapidly and at the end of the 20th century, the rate of NO publications was approximately 6,000 papers per year, with currently more than 100,000 references invoking NO listed in PubMed.” (Ghasemi, 2011)
In our earlier discussion of nitric oxide as the curing molecule in bacon, we referred to S. J. Haldane who was the first person to demonstrate that the addition of nitrite to haemoglobin (blood protein) produces a nitric oxide (NO)-heme bond, called iron-nitrosyl-hemoglobin (HbFeIINO). He showed that nitrite is further reduced to nitric oxide (NO) in the presence of muscle myoglobin (muscle protein key in supplying oxygen to the muscle) and forms iron-nitrosyl-myoglobin. It is nitrosylated myoglobin that gives cured meat, including bacon and hot dogs, their distinctive red colour and protects the meat from oxidation and spoiling. Discovering that Nitric Oxide (NO) is a key molecule in human physiology should not have been a surprise to meat scientists. There was, an understanding in meat science since the time of Haldane that the nitrate-nitrite-NO pathway was the curing reactions in meat from saltpetre to nitric oxide. It was later decided to use nitrite directly for reasons elucidated in a previous part of this series, Part 2: The Curing Molecule
When we say that the reduction of nitrite to nitric oxide occurs chemically, we refer to the non-enzymatic reduction of nitrite to nitric oxide. Ghasemi (211) gives us the technical details of this. “NO was found to be synthesized from L-arginine by the enzymes known as NO synthase (NOS) (EC 1.14.13.39) in two separate mono-oxygenation steps; first, L-arginine is converted to N-hydroxyarginine in a reaction requiring one O2 and one NADPH and the presence of tetrahydrobiopterin (BH4) and in the second step, by oxidation of N-hydroxyarginine citrulline and NO are formed. At least three NOS enzyme isoforms including neuronal, inducible, and endothelial (eNOS) have been identified and encoded by different genes.”
This non-enzymatic production of Nitric Oxide was suggested in 1997 by Ghafourifar and Richter. They postulated the “existence of mitochondrial NOS and in 1994, Lundberg and colleagues and Benjamin and colleagues demonstrated NOS-independent NO formation. Non-enzymatic NO production by one-electron reduction of nitrite, a blood and tissue NO reservoir, seems to be found everywhere and greatly accelerated under hypoxic conditions or conditions of low oxygen levels in your body tissues. This finding changes the general belief that nitrate and nitrite are waste products of NO.” (Ghasemi, 2011)
I want to refer as an important sidenote at this point to the work of Vanek (2022) which we will look at in much greater detail in a following discussion since they beautifully elucidates the reason for the importance of Nitric Oxide and how it binds to the meat protein we rely on in meat curing, forming the reddish/ pinkish colour of cured meat and giving muscles its characteristic red colour. The important point is that just as nitric oxide is produced through enzymes and non-enzymatic ways to react with myoglobin, in the same way and hugely important to meat curing is that myoglobin has also been shown to have enzymatic functions and is responsible for the decomposition of bioactive nitric oxide to nitrate. The importance of this point can hardly be over-stated! If we are able to convert L-arginine into Nitric Oxide in other ways besides indigenously through NO synthase (the enzymes responsible for oxidising nitrogen in L-Arginine to nitric oxide), and so cure meat, and should we find that this can be done through bacteria, then we still do not strictly speaking have meat curing with no nitrite present as the nitrate will be converted through bacteria in the meat to nitrite and albeit this being present at very low dosages, there will still be nitrite in the meat that we cured.
Allow me to state it again. If we are able to access L-arginine either through bacteria or enzymes directly (as we do in salt-only-long-term-cured-hams) and as a result of this do not start our curing process with nitrite (as is the case with long-term salt-only cured hams) and we are able to claim that we cure meat with no nitrite salts as we are indeed able to do at the present time, then we can not say that we eliminated nitrite from meat curing because there is the likelihood that some of the NO will be converted to nitrate which will be reduced to nitrite again and we are back at the beginning of the quest for nitrite-free curing. Stated a different way, it would seem that curing without nitrite is not possible. This is the heart of the conundrum of people propagating that meat has been cured with no nitrites in that we are dealing with REACTIVE nitrogen species and where you find the one, you are likely to find the others. Our nitrogen species of interest, when we refer to “we will find the one where we find the others” are nitrate, nitrite and nitric oxide, but as we will see further on, these are by no means the only nitrogen species we will encounter in the human muscle and in meat curing alike.
The extent to which what I suggest above is true, we will have to verify through experimentation. The rest of this document is dedicated to answering the following question: why would we want to eliminate a physiologically important species of nitrogen from our diet in any event!? So, on the one hand, is nitrite free curing a realistic goal and secondly, why would we want to do it? Are there other ways to overcome the health concerns associated with cured meats?
Effects of Nitrite in Human physiology.
– Sources of nitrogen for Human Physiology and the Value of Nitrite
The great discovery of the past few decades is that nitrate and nitrite have a fundamentally important role in our physiology and nitrite in particular, namely to act as a reservoir for nitric oxide (NO) which is a physiologically important molecule. Apart from nitric oxide being generated from the amino acid, L-Arginine, nitric oxide is generated through what is referred to as the nitrate-nitrite-Nitric Oxide pathway which is, as we have said before, exactly the same pathway of bacon curing. So, in order for this mechanism to work, we need a direct source of nitrates or nitrites and nature provided this for us in what we eat. The biggest source is vegetables which account for 60%–80% of the daily nitrate intake in a Western diet. As you will see from the table below, they not only supply us with nitrates but with nitrites directly as well. It has been shown that elevations in the blood plasma nitrite levels can occur by increasing the dietary nitrate intake. (Kobayashi, 2015)
Nitrate, nitrite and nitric oxide are closely linked as the difference between them is one oxygen atom. NO3– (nitrate), NO2– (nitrite) and NO (nitric oxide). Nitrate is reduced to nitrite through bacteria and nitrite to nitric oxide through chemical means (enzyme and non-enzyme driven). NO can be oxidized back to nitrite again and nitrite to nitric oxide. Nitric oxide, in the presence of myoglobin, can be converted directly back to nitrate. As a result of this, where one finds nitrate and bacteria such as in the mouth or digestive tract, you will always find nitrite and nitric oxide and where you have nitric oxide, one can find nitrite and nitrate. This is true in meat curing and true in the human body. “In humans and other mammals, about one-quarter of all circulating inorganic nitrate (NO3−), derived from diet or oxidation of endogenous (within the body) nitric oxide (NO), is actively taken up by the salivary glands and excreted in saliva. As a result, salivary nitrate levels are 10–20 times higher than those levels found in our blood. The mechanism behind this massive nitrate accumulation in saliva has remained elusive. The work by Qin et al. reports that the protein sialin can function as an effective nitrate transporter.” (Lundberg, 2012)
With these brief remarks, we are then thrust into the domain of the nitrate-nitrite-NO cycle in the human body. Nitrite is no longer viewed as something to be avoided at all cost, but as a chemical essential for human life and cured meat becomes by far, not the biggest contributor of nitrate and nitrite to our system, but the possibility exists for it to become an important one as we can use the same basic principles that gave us cured meat, reduce the fat and salt and find ways to introduce essential goodness of plant matter and we are confronted with the amazing opportunity to change processed food into a superfood! In this one statement, I seek to address the unfounded negative perception of nitrite, give a clue as to the possible real reason behind the health concerns related to processed meat (fat, salt, phosphates, etc) and give a roadmap for future work by imaginative food scientists in the incorporation of healthy plant matter into the sought after food group, allowing for all the conveniences that make processed-meats a well-loved and very convenient food for our era!
Have a look at the table below which gives the main dietary sources for nitrate and nitrites. Pay close attention to where hot dogs and bacon feature on the list!
Sindelar (2012), as quoted by (Kobayashi, 2015)
Hord (2009) as quoted by (Kobayashi, 2015)
When we ingest nitrates from leafy green vegetables or cured meat, it is absorbed in the upper gastrointestinal tract which comprises the mouth, salivary glands, oesophagus, stomach, and small intestine. The levels in the blood reach the highest level around 30–60 min after the nitrates have been swallowed. Approximately 25% of nitrate absorbed by the body reappears in our mouth through our salivary glands which pump it back into our mouths. Here it is reduced by the bacteria on our tongue from nitrate to nitrite. As it reaches our stomach, a part of the nitrites which we swallow is what we call protonated (adding hydrogen to the nitrite) and nitrous acid is formed which is the form that nitrite takes on when diluted into water (NO2− + H+ → HNO2). This reaction is similar to what happens to nitrite when we dilute it into the curing brine and inject it into meat which is also a more acidic environment like the stomach. Similar to meat curing, the nitrite we ingested now decomposes to form a variety of nitrogen oxides such as Nitric Oxide, the curing molecule, nitrogen dioxides (NO2), and dinitrogen trioxide (N2O3) (2 HNO2 → N2O3 + H2O, N2O3 → NO + NO2). These nitrogen oxides form additional bioactive adducts, such as S-nitrosothiols and N-nitrosamines. S-nitrosothiols sound very intimidating but are not. They are proteins discovered in the 90s and have since been shown to be key in many biochemical processes in our body. Specifically, S-nitrosothiols play a key role in the total system encompassing our heart and blood vessels, for example, the widening of blood vessels as a result of the relaxation of the blood vessel’s muscular walls and preventing thrombosis. N-nitrosamines are known to us by now as formed by the reaction of nitrite with secondary amines which can be cancer-causing.” (Kobayashi, 2015)
The next point requires us to know what gastric mucosa refers to. It is the mucous membrane layer of the stomach, which contains the glands and the gastric pits. Blood flow plays an important role in the protection of normal gastric mucosa and in the protection and healing of damaged mucosa. “Nitric Oxide production in the stomach is greatly enhanced in the presence of micronutrients that naturally occur in plants called dietary polyphenols and vitamin C or ascorbic acid, whereas because of its lower stability and shorter half-life relative to S-nitrosothiols, the released Nitric Oxide in the stomach is thought to locally contribute to increasing the gastric mucosal blood flow and mucous thickness to ensure the normal gastric physiology, and serves as the first-line host defence against harmful bacteria which we swallowed with our food. However, not all the nitrite reacts with H+(escapes the protonation) in the acidic milieu of the stomach and enters the systemic circulation, and then reaches the peripheral organs, including skeletal muscles, where it acts in an endocrine manner (like hormones) to exert NO-like activity. An interesting side note is that because the levels of nitrite in the blood are depends to a large degree on the amount of nitrate in the saliva and its reduction to nitrite, the use of antibacterial mouthwash and frequent spitting of saliva consequently decrease the plasma levels of nitrite.” (Kobayashi, 2015) We just said that Nitric Oxide production in the stomach is greatly enhanced in the presence of micronutrients that naturally occur in plants called dietary polyphenols and vitamin C or ascorbic acid. As we will see later, these substances and in particular vitamin A, C and E plays an important role as “blocking” agents by reacting with the partially digested amino acids called amines, and with secondary amines in particular called N-Nitrosamones denoting a reaction between the amine and nitroso component in nitrite, binding nitrogen and nitrogen (therefore the name, N-Nosotros-amines), blocking the formation of n-nitrosamines. Let me state it again. If we ingest nitrite with vitamins a, c, e, etc., these vitamins react with the secondary amines before nitrite can react with it, therefore blocking nitrosamine formation. This is something to look at on its own and we will not spend much more time on this important point. Here, my goal is to show that nitrite is NOT the harmful cancer-causing entity we believed it was, but turns out to be indispensable for healthy living! We can, therefore, for the moment, suspend the concerns about N-nitrosamine formation but rest assured that we will return to this in great detail! For now, let us continue with our focus on nitrites and the diagram below shows the main way we get nitrates and nitrites into our body.
(Kobayashi, 2015)
“The plasma nitrite which reaches peripheral tissues is stored in various organs. Although there have been few reports dealing with the tissue levels of nitrate/nitrite following dietary nitrate supplementation in humans, animal studies show that dietary nitrate certainly increases the tissue levels of nitrate/nitrite following an increase in the plasma levels of nitrate/nitrite, which accordingly exerts therapeutic efficacy for animal models of various disease conditions. Interestingly, while acute dietary nitrate intake increases the plasma levels of nitrite in rodents and humans, chronic dietary nitrate intake does not always increase the plasma and tissue levels of nitrite but increases the tissue levels of nitrate and S-nitrosylated products. Although the mechanism underlying this finding is yet to be clarified, there might be some redox equilibrium of nitrate-nitrite-NO after chronic dietary nitrate intake, resulting in oxidation or reduction of the tissue nitrite to form nitrate or S-nitrosylated species, respectively. On the other hand, animal models chronically fed a diet deficient in nitrate/nitrite exhibit significantly diminished plasma and tissue levels of nitrate/nitrite, resulting in increased ischemia-reperfusion injuries in the heart and liver compared with the animal models fed a normal diet. Ischaemia-Reperfusion injury (IRI) is defined as the paradoxical exacerbation of cellular dysfunction and death, following the restoration of blood flow to previously ischaemic tissues. Ischemia or ischaemia is a restriction in blood supply to any tissues, muscle group, or organ of the body, causing a shortage of oxygen. These results suggest that dietary nitrate intake is important in the maintenance of steady-state tissue levels of nitrate/nitrite for NO-mediated cytoprotection. Cytoprotection is a process by which chemical compounds provide protection to cells against harmful agents. (Kobayashi, 2015) The key point is the importance of nitrate and nitrate in our diets and the possible harmful effect of nutrition deficiency in these compounds.
“Historically, the fact that nitrate and nitrite are present in human saliva has received little attention, because no one could attribute any kind of function to these anions. However, this lack of interest ceased in the 1970s, when researchers formulated a pathophysiological model for gastric cancer based on the accumulation of nitrate in saliva. Commensal bacteria in the mouth reduce parts of the salivary-derived nitrate to nitrite (NO2−), and when swallowed into the acidic stomach, this nitrite yields reactive intermediates that can react with dietary compounds to promote the formation of N-nitrosamines (a versatile class of carcinogens in rodents). With the emergence of this theory, nitrate immediately fell into deep disgrace, and ever since that time, authorities worldwide have put strict regulations on allowable levels of nitrate in our food and drinking water.” (Lundberg, 2012)
In the 1990s, research on nitrate took an unexpected turn when two research groups independently showed that salivary nitrate was a substrate for the formation of NO, and we looked at the development of our understanding of the importance of this molecule in our lives earlier on. It was revealed that NO plays “a key role in virtually every aspect of human physiology, including regulation of cardiovascular function, cellular energetics, immune function, neurotransmission, and more. The newly described alternative means of NO generation from nitrate was fundamentally different from the NO synthase pathway; it did not use arginine as a substrate, and it was independent of NO synthases. After the discovery that nitrate could be a substrate for the formation of a potentially beneficial biological messenger, the interest in nitrate shifted away from only being focused on carcinogenesis, and instead, researchers started to study potential NO-like physiological effects of this anion. From intense research performed during the past 15 y, it is now clear that administration nitrate or nitrite has robust NO-like effects in humans and other mammals. These effects include vasodilation, reduction in blood pressure, protection against experimental ischemia-reperfusion injury, reduction in cellular oxygen consumption, reversal of metabolic syndrome, reduction in oxidative stress, stimulation of mucosal blood flow and mucus formation in the gastrointestinal tract, and more.” We will spend time further on many of these in particular looking at lifestyle diseases.
“Intriguingly, most of these nitrate effects occur at dietary doses easily achievable through a normal diet rich in vegetables. Bioactivation of nitrate requires initial reduction to the more reactive nitrite anion, and this reaction is mainly carried out by commensal bacteria in the oral cavity and to a lesser degree, the tissues by mammalian enzymes. Salivary-derived nitrite is partly reduced to NO in the acidic stomach as described above, but much nitrite also survives gastric passage and enters the systemic circulation, which is evident from the marked nitrite increase in plasma seen after ingestion of nitrate. In blood and tissues, nitrite can undergo additional metabolism to form NO and other bioactive nitrogen oxides, including S-nitrosothiols. A number of enzymes and proteins have been shown to act as nitrite reductases, including deoxygenated haemoglobin, myoglobin, xanthine oxidase, mitochondrial respiratory chain enzymes, and more.” (Lundberg, 2012)
This matter of nitrate-nitrite-Nitric Oxide as the reaction sequence from nitrate in saliva becomes very interesting to us in the meat curing industry for one specific reason. When we surveyed the approach taken by the industry and the US government in particular, we noted in Part 3: Steps to secure the safety of cured meat, of our series that the direct application of nitrite was seen as a way to bypass the first bacteria mediated reduction step of nitrate to nitrite. The reasons given by industry and scientists alike was that it would yield better control in the curing process amongst others, as it relates to the lowest possible dosage of nitrite to effect curing since the dose dependency of the toxicity of nitrites was recognised from very early.
Lundberg (2012) surveyed the work of Qin in identifying sialin as the nitrate transporter to the saliva. This is relevant to curing. Lundberg describes a disorder which leads to ineffective transport of nitrate as follows, “Mutations in the sialin gene cause Salla disease and infantile sialic acid storage disorder, which are serious autosomal recessive lysosomal storage disorders characterized by early physical impairment and mental impairment.”
A fibroblast is a type of cell that contributes to the formation of connective tissue. It secretes collagen proteins that help maintain the structural framework of tissues. “Fibroblasts from patients with infantile sialic acid storage disorder show a lower nitrate transport activity compared with healthy controls. The work by Qin et al. also tested the importance of sialin for nitrate transport in the pig in vivo. Interestingly, adenovirus-dependent expression of a sialin mutant vector (sialinH183R) in the salivary gland decreases NO3− secretion in saliva after ingestion of a nitrate-rich diet compared with control animals.” (Lundberg, 2012)
“Sialin is expressed not only in the salivary glands but also in the brain, heart, lung, kidney, and liver, although seemingly at lower levels. The functional importance of nitrate transport into cells in these tissues would be of interest to study. In this context, it is interesting to note that nitrate metabolism does, indeed, occur in mammalian cells, although to a much lesser degree than in bacteria. The work by Jansson et al. reported on a functional mammalian nitrate reductase in numerous tissues, including liver, kidney, and intestines. Xanthine oxido reductase was identified as the major mammalian nitrate reductase, but the study indicated the presence of other unidentified nitrate reductases as well.” (Lundberg, 2012) The observation that nitrate metabolism occurs in mammalian cells, although to a much lesser degree than in bacteria should not escape our notice. I discussed the matter with a collaborator on key projects, Richard Bosman and we speculated that the reason for the curing in long-term salt-only-dry-cured hams probably has more to do with the relaxing of the muscles as a result of early cell breakdown and the accompanying invasion of bacteria able to oxidize L-arginine than with the endogenous oxidants in the meat. This fact possibly further points to a symbiotic evolution of humans with oral cavity bacteria positioned to fulfil this vital role of reducing nitrate to the more reactive nitrite.
“The work by Qin et al. proposes that sialin functions as the major NO3− uptake system in salivary gland cells; however, a remaining question is how this nitrate is further transported to saliva through the apical portion of the cells. Sialin seems to be a versatile anion transporter that also mediates H+-dependent transport of NO2−, aspartate, and glutamate. Previously, antagonism between nitrate, perchlorate, iodine, and thiocyanate for secretion in human saliva was shown, but in the work by Qin et al., these anions are not studied. It will be of interest to study if sialin also transports these anions. Definitive evidence for a functional role of sialin in nitrate transport and systemic nitrite/NO homeostasis in humans is lacking, but with the identification of this protein as an important nitrate transporter, it now seems possible to study this area. One approach could be to study the nitrate–nitrite–NO pathway in genetically engineered mice or perhaps, patients with Salla disease. Are salivary and plasma levels of nitrate/nitrite different in these patients? Do these animals or the patients exhibit any signs of systemic NO deficiency, including increased blood pressure, altered blood flow responses, different cellular energetics, or others? In the case that NO homeostasis is disturbed in Salla disease, would the patients benefit from substitution with nitrite?” (Lundberg, 2012)
This is the relevant question. Look at the possible suggestions. Is it possible to bypass nitrate and the bacterial reduction to nitrite and instead, would a solution be to administer nitrite directly as happens when we ingest nitrate which is transported to the saliva glands and in the mouth, are converted to nitrite, which, in the mouth and in the reducing environment in the stomach is changed to the physiologically vital nitric oxide? Lundberg (2012) puts his finger on the issue when he asks, “By giving nitrite instead of nitrate, one could bypass the initial nitrate transport step that might be disturbed in these patients, and NO and other bioactive nitrogen oxides would form directly from nitrite in blood and tissues.” He points to the fact that this therapeutic approach “was recently successfully tested in another genetic disorder involving a disturbed NO homeostasis.” Homeostasis refers to a self-regulating process by which biological systems maintain stability while adjusting to changing external conditions. “Another approach could be to study the proposed negative consequences of nitrate transport. If salivary nitrate transport promotes nitrosamine formation, which has been believed for a long time, are nitrosamine levels and occurrence of gastric malignancies lower in subjects lacking the transporter?” (Lundberg, 2012)
Huizing reports by 2021 that “plasma-membrane nitrate transport in salivary gland acinar cells, remains enigmatic.” (Huizing, 2021) Our hiatus into this question has, however, not been without reward.
We have seen the widespread distribution of nitrate to physiologically vital sites in the body;
We glimpsed at the key role of nitrite in the blood plasma, mainly derived from ingested nitrate and nitrates.
We see how other scientists in other fields of study came to the same conclusion as food scientists in the early 1900 namely that a direct application of nitrite, bypassing the time and bacteria dependant reduction step of nitrate has beneficial consequences.
In the discussion about possible negative effects of nitrite, one very important point to remember is that our overall natural design favours an adequate intake of nitrites. This can be seen by its presence in our blood. Here, nitrite is reduced to nitric oxide.
Gladwin (2008) that “recently, multiple physiologic studies have surprisingly revealed that nitrite represents a biologic reservoir of NO that can regulate hypoxic vasodilation, cellular respiration, and signalling.” They summarise that “studies suggest a vital role for deoxyhemoglobin- and deoxymyoglobin-dependent nitrite reduction. Biophysical and chemical analysis of the nitrite-deoxyhemoglobin reaction has revealed unexpected chemistries between nitrite and deoxyhemoglobin that may contribute to and facilitate hypoxic NO generation and signalling. The first is that haemoglobin is an allosterically regulated nitrite reductase, such that oxygen binding increases the rate of nitrite conversion to NO, a process termed R-state catalysis. The second chemical property is oxidative denitrosylation, a process by which the NO formed in the deoxyhemoglobin-nitrite reaction that binds to other deoxyhemes can be released due to heme oxidation, releasing free NO. Third, the reaction undergoes a nitrite reductase/anhydrase redox cycle that catalyzes the anaerobic conversion of 2 molecules of nitrite into dinitrogen trioxide (N2O3), an uncharged molecule that may be exported from the erythrocyte. We will review these reactions in the biologic framework of hypoxic signalling in blood and the heart.”
It is interesting that nitric oxide produced in the endothelium is oxidised to nitrite. In this instance, one could say that it “bypasses” the intestinal section where it could react with amino acids to form n-nitrosamines which some of them can cause cancer. Rassaf (2014) states that Nitric Oxide is produced in the body from the amino-acid L-arginine by the NO-synthases (NOSs). Three different NOSs exist: the endothelial NOS (eNOS, NOS III), the inducible NOS (iNOS, NOS II) and the neuronal NOS (nNOS, NOS I). This may be one way that the body uses to “manage” the possible harmful effects of nitrite but there are others as we have already eluded to and will look at in greater detail further on, namely ways to “block” nitrite through ingested vitamins. Still, there is another important mechanism which we will discuss in the future when we focus on n-nitrosamines and ways to mediate its possible harmful effect. Note that making it mandatory to include vitamin C in cured meats has been a strategy employed by the industry and regulated by governments from very early on. I will say a bit more about this at the end of this article.
Let’s return to the endothelial. The endothelial is the largest organ system in the body. I repeat the definition as I realise that these concepts may be new to many of the readers and repetition aids learning! It refers to a single layer of cells, called endothelial cells which lines the inside of all blood vessels (arteries, veins and capillaries). Inductable NOS is expressed after cell activation only and then produces NO for comparatively long periods of time (hours to days) in response to autoimmune and chronically inflammatory diseases in humans and neurodegenerative diseases and heart infarction, during tumour development, after transplantation, during prostheses failure and myositis. (Kröncke, 1998) Neuronal or nNOS relates to the brain. “Brain nNOS exists in particulate and soluble forms and the differential subcellular localization of nNOS may contribute to its diverse functions and has been implicated in modulating physiological functions such as learning, memory, and neurogenesis, as well as being involved in a number of human diseases.” (Zhou, 2009)
Let’s return to Gladwin (2008) who now describes a fascinating cycle of Nitric Oxide in the blood which relies on its conversion to nitrite. As we have seen above, Nitric Oxide is produced in endothelium and then diffuses to adjacent smooth muscle to activate soluble guanylyl cyclase that produces cGMP, and ultimately produces smooth muscle relaxation. Nitric oxide is subject to rapid inactivation reactions with haemoglobin that greatly limit its lifetime in blood, however recent studies suggest that NO formed from endothelial NO synthases is also oxidized by oxygen or plasma ceruloplasmin to form nitrite. Nitrite transport in blood provides an endocrine (from glands) form of NO that is shuttled from the lungs to the periphery while limiting the exposure of authentic NO to the scavenging red cell environment. Then during the rapid haemoglobin deoxygenation from artery to vein, the nitrite is reduced back to NO. Such a cycle conserves NO in the one-electron oxidation state. In this model, the nitrite pool represents the “live payload,” only one electron away from NO.”
If the body then generates enough Nitric Oxide, is there a requirement for additional dietary intake of nitrate or nitrite? “It has been suggested that the nitrate-nitrite-NO pathway serves as a backup system to ensure sufficient NO generation under hypoxic conditions when NOS may be malfunctioning.” (Ghasemi, 2011)
“It has been shown that 3-day dietary supplementation with sodium nitrate (0.1 mmol/kg/day) could reduce significantly diastolic blood pressure in non-smoking healthy volunteers. Recently, a large cohort study of 52,693 patients from 14 countries with acute coronary syndrome, of whom 20% were on chronic nitrate, demonstrated that chronic nitrate therapy (medication routinely taken at home and started at least 7 days prior to index event) was associated with reduced severity of myocardial injury in response to acute coronary events. The result showed that the proportion of these subjects with ST-segment elevation myocardial infarction was 41% in nitrate-naïve patients compared to only 18% in nitrate users and conversely a higher percent of nitrate users (82%) presented with non-ST-segment elevation acute coronary syndrome compared to 59% in nitrate-naïve patients.” (Ghasemi, 2011)
“Increasing nitrate or nitrate dietary intake provides significant cardioprotection against ischemia-reperfusion (I/R) injury in mice and it has been proposed that nitrite-/nitrate-rich foods may provide protection against cardiovascular conditions characterized by ischemia. It has been suggested that the nitrate-nitrite-NO pathway serves as a backup system to ensure sufficient NO generation under hypoxic conditions when NOS may be malfunctioning.” (Ghasemi, 2011)
“Abundant consumption of fruits and vegetables, especially green leafy vegetables, is associated with lower risk of cardiovascular disease. It has been proposed that inorganic nitrate, which is found in vegetables with a high concentrations, i.e. >2000-3000 mg/nitrate/kg, is the major factor in contributing to the positive health effects of vegetables via bioconversion to nitrite, NO, and nitroso-compounds, NOx intake now being considered as a dietary parameter for assessing cardiovascular risk.” (Ghasemi, 2011)
“Any intervention that increases blood and tissue concentration of nitrite may provide cardioprotection against I/R injury because it serves as a NOS-independent source of NO and reacts with thiols to form S-nitrosothiols. Nitrate-nitrite-NO pathway can be boosted by exogenous administration of nitrate or nitrite and this may have important therapeutic as well as nutritional implications. However, additional studies are required to clarify the protective roles of nitrate, considering the medical status of subjects, concomitant use of inhibitors of endogenous nitrosation (e.g. vitamin C and E), or foods containing high levels of nitrosatable precursors (e.g. fish). Some individuals, including those with high blood pressure and atherosclerosis, may benefit from increased nitrate while those with oesophagal dysplasia should avoid foods with high concentration of nitrate.” (Ghasemi, 2011)
The value of nitrite in the human body, however, goes far beyond only a reservoir of Nitric Oxide. We have eluded time and time again to many of the benefits and we now drill down on some of the different benefits or tahre, its role in resolving some of the negative lifestyle diseases prevalent in our modern era. “Nitrite-induced transnitrosylation in organs might be an alternative in vivo nitrite signalling for the mammalian biology including protection of protein thiols from irreversible oxidation, transcriptional modulation, and posttranslational regulation of most classes of proteins present in all cells, and also that changes in plasma nitrite levels even within the physiological ranges (e.g., postprandial and fasting) can affect tissue levels of S-nitrosothiol and subsequent cellular biology.” (Kobayashi, 2015)
-> Protective Effects of Dietary Nitrate/Nitrite on Lifestyle-Related Diseases
Kobayashi (2015) reviewed nitrites’ protective effect on lifestyle-related diseases. They write: “Lifestyle-related disease is a chronic disease characterized by oxidative and proinflammatory state with reduced NO bioavailability. The cellular redox balance in these patients shifts toward a more oxidizing state which affects a number of protein functions at the transcriptional and posttranslational levels, consequently disrupting the cellular homeostasis. However, increased NO bioavailability can improve the intracellular redox environment by S-nitrosylation-mediated modulation of most classes of proteins present in all cells. Recently, accumulating evidence has suggested that dietary nitrate/nitrite improves the features of lifestyle-related diseases by enhancing NO availability, and thus provides potential options for prevention and therapy for these patients. Based on the recent evidence, the beneficial effects of a diet rich in these components are discussed below, focusing on insulin resistance, hypertension, cardiac ischemia/reperfusion injury, chronic obstructive pulmonary disease (COPD), cancer, and osteoporosis.”
Insulin Resistance
“The insulin receptor shares a signalling pathway with the activation of endothelial NOS (eNOS) to regulate the postprandial blood flow and efficient nutrient disposition to peripheral tissues. Therefore, insulin resistance is always associated with impaired NO availability, suggesting that a reciprocal relationship exists between insulin activation and endothelial function. Insulin resistance is improved by NO at various levels including insulin secretion, mitochondrial function, modulation of inflammation, insulin signalling and glucose uptake. For example, insulin-stimulated NO production has physiological consequences resulting in capillary recruitment and increased blood flow in skeletal muscle, leading to efficient glucose disposal.” (Kobayashi, 2015)
However, the most important mechanism to improve insulin resistance might be at the post-receptor level of insulin signalling. In diabetic states, increased adiposity releases free fatty acids and produces excessive reactive oxygen species (ROS) through a toll-like receptor 4 (TLR4)-mediated mechanism, which activates a number of kinases and phosphatases, and then disrupts the balance of protein phosphorylation/dephosphorylation associated with insulin signalling. The mechanisms underlying the NO-mediated beneficial effects on insulin resistance are as follows: First, NO suppresses the TLR4-mediated inflammation and ROS production by inactivating IkB kinase-β/nuclear factor-κB (IκκB/NF-κβ), the main trigger for the induction of a number of proinflammatory cytokines. Second, Wang et al., indicated that NO mediates the S-nitrosylation of protein-tyrosine phosphatase 1B (PTPB1) and enhances the effects of insulin. Because PTPB1 dephosphorylates the insulin receptor and its substrates, attenuating the insulin effect, its phosphatase activity tends to be suppressed by eNOS-mediated S-nitrosylation. In contrast, when the vascular eNOS activity is impaired, PTPB1 suppresses the downstream signalling to PI3K/Akt, leading to insulin resistance. Therefore, NO might act as a key regulatory mediator for the downstream signalling linking glucose transporter 4 (GLUT4) translocation and glucose uptake. Third, Jiang recently reported that NO-dependent nitrosylation of GLUT4 facilitates GLUT4 translocation to the membrane for glucose uptake, and improves insulin resistance. Fourth, excess nutrients also overproduce superoxide in the mitochondrial respiratory chain, leading to the subsequent formation of ROS. NO can inhibit mitochondrial ROS production through the S-nitrosylation of mitochondrial respiratory chain complex 1 enzyme and by improving the efficiency of oxidative phosphorylation in the mitochondria.” (Kobayashi, 2015)
“Indeed, the therapeutic potential of dietary nitrate/nitrite has been supported by recent studies demonstrating the improvements of insulin resistance in humans and animals as a result of its enhancing the NO availability in plasma and tissues. As mentioned above, insulin resistance always accompanies metabolic and endothelial dysfunction, which leads to hypertension and atherosclerosis. Enhancement of the availability of NO might therefore be a promising strategy for the prevention and treatment of patients with not only insulin resistance but also endothelial dysfunction.” (Kobayashi, 2015)
-> Cardiac Ischemia/Reperfusion Injury
“During heart ischemia, ATP is progressively depleted in cardiac muscle cells, which impairs ion pumps, leads to the accumulation of calcium ions, and consequently damages the cell membrane stability. On reperfusion, the cardiac muscle cells are further injured, because in the mitochondria, ROS are produced in large quantities due to massive electron leaks and the formation of superoxide with the resupplied oxygen, which denatures cytosolic enzymes and destroys cell membranes by lipid peroxidation. ROS-mediated dysfunction of the sarcoplasmic reticulum also induces massive intracellular calcium overload, leading to the opening of the mitochondrial permeability transition pore and causing cell apoptosis or necrosis, depending on the intracellular ATP levels. The availability of vascular NO would thus be expected to be impaired due to the reduced NOS activity in ischemia and subsequent consumption by superoxide during reperfusion, resulting in severe ischemia/reperfusion injury.” (Kobayashi, 2015)
“Nitrite, nitrate, and NO-related compounds (e.g., S-nitrosothiols) are constitutively present in blood and tissues. The nitrite level in cardiac tissue is a couple of times higher than that in plasma due to an unknown form of active transport from blood to tissues or due to the oxidation of endogenously generated-NO to nitrite by ceruloplasmin, and serves as a significant extravascular pool for NO during tissue hypoxia. Carlström et al., showed that dietary nitrate increased the tissue levels of nitrite and S-nitrosothiols in the heart, and attenuated oxidative stress and prevented cardiac injury in Sprague-Dawley rats subjected to unilateral nephrectomy and a high-salt diet. Shiva et al., recently showed that the nitrite stored in the heart and liver via systemic and oral routes augmented the tolerance to ischemia/reperfusion injury in the mouse heart and liver.” (Kobayashi, 2015)
“Although the genetic overexpression of eNOS in mice attenuates myocardial infarction, in general, the protective effects of NO on cardiac ischemia/reperfusion injury depend on the local stock of nitrite and its subsequent reduction to NO at the critical moment when NOS activity is lacking under hypoxic conditions. Indeed, the tissue levels of S-nitrosothiols (NO-mediated signalling molecules) are enhanced through the nitrite reduction due to NOS inhibition, hypoxia, and acidosis, suggesting that the tissue nitrite stores can be regarded as a backup and on-demand NO donor. There are a number of factors that have been demonstrated to reduce nitrite in the tissues, including deoxyhemoglobin, deoxymyoglobin, xanthine oxidoreductase, heme-based enzymes in the mitochondria and acidosis during ischemia. In patients with coronary heart disease, the different consequences of myocardial infarction may depend on the patient’s daily intake of nitrate/nitrite. Indeed, Bryan et al., showed that dietary nitrite (50 mg/L) or nitrate (1 g/L) supplementation in drinking water for seven days maintained higher steady-state levels of nitrite and nitroso compounds, as well as nitrosyl-heme, in mouse cardiac muscle, and these mice exhibited a smaller cardiac infarct size after ischemia/reperfusion injury compared with control mice fed a diet deficient in nitrate/nitrite for seven days. These findings suggest that this protective nitrate/nitrite may be derived at least in part from dietary sources.” (Kobayashi, 2015)
“Shiva et al., demonstrated that the cytoprotective effects of nitrite on ischemia/reperfusion injury are mediated by post-translational S-nitrosylation of complex 1 in the mitochondrial respiratory chain, which consequently inhibits the overall mitochondrial ROS formation and apoptotic events. Another possible cytoprotective effect of nitrite may be mediated by the effects of S-nitrosylation on the intracellular Ca2+ handling, which decreases Ca2+ entry by inhibiting L-type Ca2+ channels and increasing the sarcoendoplasmic reticulum (SR) Ca2+ uptake by activating SR Ca2+ transport ATPase (SERCA2a) [102]. These effects will lead to an attenuation of the increase in cytosolic Ca2+ during ischemia and Ca2+ overload during reperfusion.” (Kobayashi, 2015)
“Intriguingly, recent large-scale epidemiological studies reported the preventive effects of antioxidant supplementations including vitamins E, C, and beta carotene rich in fruits and vegetables on cardiovascular disease, whereas no beneficial effects were shown in other studies, and in some cases, a decrease in cardiovascular protection with these supplementations was observed. On the other hand, a number of epidemiological studies have shown the preventive effects of fruits and vegetables on coronary heart disease. It should be noted that the consumption of an appropriate amount of fruits and vegetables, which might contain balanced doses of nitrate/nitrite and vitamins, might be more effective with regard to health maintenance and improvement than antioxidant supplementation alone.” (Kobayashi, 2015) It is this finding in particular that gives direction to my work with two collaborators Richard Bosman and Dr Jess Goble. Whether we will succeed in our quest, time will tell but we have some impressive early breakthoughs and with solid support of scientists, industry professionals and inventors of new technology which has the potential to unluck the application of these fruits and vegetables to meat, we are hopeful and extremely motivated!
-> Chronic Obstructive Pulmonary Disease (COPD)
“COPD is considered to be a lifestyle-related disease because long-term tobacco smoking and subsequent chronic bronchitis are causally associated with this disease. Varraso et al., recently reported the importance of a healthy diet in multi-interventional programs to prevent COPD. They showed that high intake of whole grains, polyunsaturated fatty acids, nuts, and long chain omega-3 fats, and low intake of red/processed meats, refined grains and sugar-sweetened drinks, were associated with a lower risk of COPD in both women and men.” (Kobayashi, 2015)
“Because cured meats such as bacon, sausage and ham contain high doses of nitrite for preservation, antimicrobial and colour fixation, epidemiological studies have demonstrated that the consumption of cured meats is positively linked to the risk of newly diagnosed COPD. Nitrite generates reactive nitrogen species, which may cause nitrosative damage to the lungs, eventually leading to structural changes like emphysema. This is supported by an animal study in which rats chronically exposed to 2000 and 3000 mg/L of sodium nitrite in their drinking water for two years showed distinct lung emphysema. However, the dose of nitrite used in that study was 250–350 mg/kg/day, which was too high to compare with those achieved in standard human diets.
In fact, cured meats have been reported to generally comprise only 4.8% of the daily nitrite intake, and 93% of the total ingestion of nitrite is derived from saliva, suggesting that cured meats provide minimal contributions to the human intake of nitrite, even if they are frequently consumed. In addition, the recent nitrite levels in processed meats have been approximately 80% lower than those in the mid-1970s in the US. Therefore, discussions encompassing all ingested sources of nitrite should consider whether or not the nitrite derived only from the consumption of cured meats might be responsible for the development of COPD.” (Kobayashi, 2015)
“On the other hand, a number of epidemiological studies have shown the beneficial effects of n-3 fatty acids, vitamins, fruits and vegetables on lung functions and the risk of COPD. Although it may be difficult to isolate the specific effects of these dietary nutrients, as discussed above, the nitrate and nitrite derived from vegetables and fruits are reduced to NO, which is followed by the formation of S-nitrosothiols, rather than the formation of nitrosamines especially in the presence of reducing agents such as vitamin C and E in the stomach. It has been shown that high dietary nitrate intake does not cause the expected elevation of the gastric nitrite concentrations or appreciable changes in the serum nitrite concentrations.” (Kobayashi, 2015) As I stated previously, these findings do not cause the industry to sit back and proclaim, “you see, consumption of cured meat is safe” even though the validation is encouraging – in the case of me and my collaborators it energises us to do even better and work to turn cured meat into a superfood.
“As mentioned above, different from the effects of the direct elevation of nitrite concentration in the plasma, the entero-salivary route of dietary nitrate/nitrite might enhance the availability of NO through the formation of S-nitrosothiols and its transnitrosylation to the other thiol residues of proteins, suggesting that, depending on the tissues and organs, separate metabolic pathways might exist for NO availability in this entero-salivary route. Consistent with this idea, Larsen et al., recently demonstrated that acute intravenous infusion of nitrite enhanced the plasma levels of nitrite, whereas it did not affect the oxygen consumption (VO2) or the resting metabolic rate (RMR) in humans. Instead, dietary nitrate significantly reduced the VO2 and RMR by improving the mitochondrial respiratory chain function and enhancing efficient O2 consumption, suggesting that rather than direct nitrite infusion to enhance the plasma nitrite levels, biologically active nitrogen oxide (including the S-nitrosothiols produced in the stomach) might be an important molecule for the transfer of biological NO activity for cardiopulmonary function [126]. Because COPD is a state of protein-energy malnutrition due to an increased resting metabolic rate and VO2, the effects of dietary nitrate on the reduction of the RMR and VO2 might be advantageous for patients with COPD.” (Kobayashi, 2015)
“Whether the role of NO in COPD is protective or pathogenic depends on the origin and concentration range of NO. NO activity derived from dietary nitrate and constitutive NOS might be protective against COPD largely through the S-nitrosothiol-mediated mechanism including inhibition of the noncholinergic nonadrenergic nerve activity, bronchial smooth muscle relaxation, reduction of airway hyperresponsiveness, downregulation of the proinflammatory activity of T lymphocytes, and antimicrobial defence. However, the deleterious effects of NO on the development of COPD might be derived from iNOS-mediated pro-inflammatory signalling, which is consequently (not causally) reflected by the huge amount of NO in the exhaled air of patients with COPD.” (Kobayashi, 2015)
“Recent human studies have demonstrated that dietary nitrate (beetroot juice containing approximately 200–400 mg of nitrate) improved the exercise performance and reduced blood pressure in COPD patients. However, large-scale epidemiological evidence of the impact of nitrate is still lacking.” (Kobayashi, 2015)
-> Lowering Blood Pressure
An obvious benefit of nitrite is its role as a reservoir of Nitric Oxide which is a key molecule which blood pressure. The blood pressure-lowering and performance-enhancing effects of nitrites have been known for many years. (Keller, 2017) This is due to the fact that the nitrite anion (NO–2) acts as an endogenous nitric oxide source. (Keszler, 2008) Nitrite is reduced to nitric oxide (NO). “One major mechanism of nitrite reduction is the direct reaction between this anion and the ferrous heme group of deoxygenated haemoglobin.” The oxidation reaction of nitrite with oxyhemoglobin (oxyHb) which is formed by the combination of haemoglobin with oxygen, is also well established and generates nitrate and methemoglobin (metHb). (Keszler, 2008)
“Increased consumption of fruits and vegetables is associated with a reduction of the risk of cardiovascular disease. The DASH studies recommended the consumption of diets rich in vegetables and low-fat dairy products to lower blood pressure, and these effects are thought to be attributable to the high calcium, potassium, polyphenols and fiber and low sodium content in these food items. However, vegetable diets containing high nitrate levels increase the plasma levels of nitrate and nitrite, which are the physiological substrates for NO production. Accumulating evidence has recently indicated that the nitrate/nitrite content of the fruits and vegetables could contribute to their cardiovascular health benefits in animals and humans.” (Kobayashi, 2015)
“A number of publications have demonstrated that dietary nitrate reduces blood pressure in humans. Larsen et al., reported that the diastolic blood pressure in healthy volunteers was reduced by dietary sodium nitrate (at a dose of 0.1 mmol/kg body weight per day) corresponding to the amount normally found in 150 to 250 g of a nitrate-rich vegetable, such as spinach, beetroot, or lettuce. Webb et al., studied the blood pressure and flow-mediated dilation of healthy volunteers, and showed that the vasoprotective effects of dietary nitrate (a single dose of 500 mL of beetroot juice containing 45.0 ± 2.6 mmol/L nitrate), were attributable to the activity of nitrite converted from the ingested nitrate [86]. Kapil et al., also showed a similar finding that consuming 250 mL of beetroot juice (5.5 mmol nitrate) enhanced the plasma levels of nitrite and cGMP with a consequent decrease in blood pressure in healthy volunteers, indicating that there was soluble guanylate cyclase-cGMP-mediated vasodilation following a conversion of the nitrite to bioactive NO. They later presented the effects of dietary nitrate on hypertension, and showed the first evidence that daily dietary nitrate supplementation (250 mL of beetroot juice daily) for four weeks reduced the blood pressure, with improvements in the endothelial function and arterial stiffness in patients with hypertension. Because arterial vascular remodelling is the major histological finding associated with ageing, these vascular structural changes represent vascular wall fibrosis with increased collagen deposits and reduced elastin fibers, which result in arterial stiffening and subsequent hypertension in elderly patients. Sindler et al., recently demonstrated that dietary nitrite (50 mg/L in drinking water) was effective in the treatment of vascular ageing in mice, which was evidenced by a reduction of aortic pulse wave velocity and normalization of NO-mediated endothelium-dependent dilation. They showed that these improvements were mediated by reduction of oxidative stress and inflammation, which were linked to mitochondrial biogenesis and health as a result of increased dietary nitrite. These beneficial effects were also evident with dietary nitrate in their study, suggesting that dietary nitrate/nitrite may be useful for the prevention and treatment of chronic age-associated hypertension.” (Kobayashi, 2015)
“In addition, hypertension is also a major cause of ischemic heart and cardiac muscle remodelling, which lead to congestive heart failure. Bhushan et al., reported that dietary nitrite supplementation in drinking water (50 mg/L sodium nitrite, for nine weeks) increased the cardiac nitrite, nitrosothiol, and cGMP levels, which improved the left ventricular function during heart failure in mice with hypertension produced by transverse aortic constriction. They also showed that dietary nitrite improved the cardiac fibrosis associated with pressure-overloaded left ventricular hypertrophy through NO-mediated cytoprotective signalling. Although a number of studies on the acute effects of dietary nitrate have been conducted using animal models and healthy humans, more evidence in patients with hypertension, as well as additional studies on the long-term effects of dietary nitrate, will be needed in the future.” (Kobayashi, 2015)
-> Cancer
“In the stomach, swallowed nitrite is decomposed to form a variety of nitrogen compounds, including N-nitrosoamines. In the 1950s, Magree et al., first reported that N-nitrosodimethylamine caused malignant primary hepatic tumours in rats. After this report, a number of studies followed in relation to the carcinogenic effects of N-nitroso compounds in animal models. In particular, the dietary intake of red and cured meats was found to be associated with an increased risk of certain types of cancer due to the relatively large amounts of nitrite added. However, the methodological aspects have been challenged concerning the high dose of nitrosatable amines, and the physiological difference between animals and humans.” (Kobayashi, 2015)
“In the stomach, the nitrosonium ion (NO+) derived from nitrite can bind to thiol compounds (R-SH) and amines (especially secondary amines: R1-NH-R2), forming S-nitrosothiol and N-nitrosamine, respectively. However, while N-nitrosamine formation occurs even at neutral or basic pH, S-nitrosothiol formation tends to occur only under acidic conditions. In addition, this reaction kinetically occurs much more easily than N-nitrosamine formation, particularly in the presence of vitamins C and E and polyphenols, which are highly present in fruits and vegetables, which also eliminate potent nitrosating agents such as the N2O3 formed from nitrite by decomposing them to NO. This might partly explain why patients with achlorhydria and non-vegetarians eating large amounts of cured meats are at risk of developing gastric cancer.” (Kobayashi, 2015)
“However, this idea appears to be inconsistent with the belief that dietary nitrite is a major cause of cancer. This is because, according to the average nitrate/nitrite intake of adults in the US, most of the daily nitrate intake (around 90%) comes from vegetables, and the nitrite intake is primarily derived from recycled nitrate in the saliva (5.2–8.6 mg/day nitrite), with very little coming from cured meats (0.05–0.6 mg/day nitrite in 50g/day cured meats) and other dietary sources (0–0.7 mg/day nitrite) [136], suggesting that the entero-salivary route may be the more important source of nitrosamine exposure than exogenous intake including cured meats, that is, spitting out saliva all day long might prevent cancer development more effectively than cutting cured meats. However, recent experimental and epidemiological studies could not demonstrate a positive relationship between nitrate consumption and the risk of cancer, and the Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives concluded in 2008 that there was no evidence that nitrate was carcinogenic in humans. Consistent with this, recent studies have found no link between dietary nitrate and cancer.” (Kobayashi, 2015)
“Bradbury et al., reported a large-scale study (>500,000 participants) of the associations between fruit, vegetable, or fiber consumption and the risk of cancer at 14 different sites. They showed that there was an inverse association between fruit intake and the risk of upper gastrointestinal tract and lung cancer, as well as an inverse association between fiber intake and liver cancer. The dietary intake of vegetables, as well as fruits and fiber, was inversely associated with the risk of colorectal cancer, suggesting that there is little evidence that vegetable intake is associated with the risk of any of the individual cancer sites reviewed.” (Kobayashi, 2015)
“However, chronic inflammation, including inflammatory bowel disease and Helicobacter pylori-induced gastritis induce inducible NOS (iNOS) and generate large quantities of NO, forming nitrosating and oxidant species such as N2O3 and peroxynitrite, which might cause mutagenesis through deamination, nitration of DNA, or inhibition of the DNA repair system. Depending on the sites and amounts of NO generation, NO might represent a double-edged sword in the sense that it confers both protective and deleterious effects on cancer development.” (Kobayashi, 2015)
“Meta-analyses of primary and secondary cancer prevention trials of dietary antioxidant supplements, such as beta carotene, vitamins A, C, and E, showed a lack of efficacy, and on the contrary, an increased risk of mortality. Although the general role of NO in carcinogenesis is complicated, and many unknown mechanisms remain to be resolved, the dietary nitrate/nitrite (at least that obtained from plant-based foods such as fruits and vegetables) has obvious inhibitory effects on cancer risk by playing some synergistic role with other nutrients in these foods.” (Kobayashi, 2015) It is again findings like these that give direction to our product developments.
-> Osteoporosis
“Lifestyle habits, such as smoking, alcohol intake, little or no exercise, and an inadequate amount of calcium intake all influence the calcium-vitamin D metabolism and bone mineral density, in some cases leading to osteoporosis, particularly in postmenopausal women. The implications of NOS-mediated NO in the regulation of bone cell function have been well described in a number of publications. For example, iNOS-induced NO production following stimulation with proinflammatory cytokines, such as interleukin 1 (IL-1) and tumor necrosis factor-α (TNF-α), inhibits bone resorption and formation, resulting in osteoporosis in patients with inflammatory diseases such as rheumatoid arthritis. On the other hand, eNOS, a constitutive NO synthase, plays an important role in regulating osteoblast activity and bone formation, because eNOS knockout mice exhibit osteoporosis due to defective bone formation, and eNOS gene polymorphisms were reported to be causally linked to osteoporosis in postmenopausal women.” (Kobayashi, 2015)
“In addition, Wimalawansa et al., showed that some of the beneficial effects of estrogen on bone metabolism are mediated through a NO-cGMP-mediated pathway, suggesting that NO donor therapy might provide a promising alternative to estrogen therapy. In this context, it has been shown that organic nitrate NO donors, such as glycerol trinitrate, isosorbide dinitrate and mononitrate all have beneficial effects on experimental and clinical osteoporosis, and a number of epidemiological studies also indicated that a high fruit and vegetable intake appears to have a protective effect against osteoporosis in men and pre- and postmenopausal women. However, few studies have been conducted to evaluate the detailed mechanism by which inorganic nitrate/nitrite prevents osteoporosis at the molecular level, and thus further basic research will be needed for this purpose.” (Kobayashi, 2015)
-> Methemoglobinemia (MetHb)
A negative effect of nitrite in the body relates to its link with methemoglobinemia. It is historically this link which contributed to cast nitrite in a negative light and day plays a dominant role in establishing what the WHO regards as safe levels of ingested nitrites.
“Methemoglobinemia (MetHb) is a blood disorder which the US National Institute of Health defines as occurring when “an abnormal amount of methemoglobin is produced.” They explain that “hemoglobin is the protein in red blood cells (RBCs) that carries and distributes oxygen to the body. Methemoglobin is a form of hemoglobin. Inherited (congenital) methemoglobin occurs when the disorder “is passed down through families.” Our interest is in what is referred to as acquired MetHb which is “more common than inherited forms and occurs in some people after they are exposed to certain chemicals and medicines.” One such chemical is nitrites. (National Libary of medecine) “Elevated levels of nitrite in the blood can trigger the oxidation of hemoglobin, leading to methemoglobinemia.” Keszler (2008) suggests a simplified model of the kinetics involved where the end products of the reaction are methemoglobin (metHb) and nitrate.
The “World Health Organization (WHO) used data based on the risk of methemoglobinemia to set an acceptable daily intake (ADI) for nitrate of 3.7 mg/kg body weight per day, equivalent to 222 mg nitrate per day for a 60-kg adult, and nitrite of 0.07 mg/kg body weight per day, equivalent to 4.2 mg nitrite per day for a 60-kg adult. (Keller, 2017)
The upper limit represented by the WHO ADI corresponds to the concentration of dietary nitrate that lowers blood pressure in normotensive and hypertensive adults. (Keller, 2017)
Very high concentrations of nitrate in drinking water may cause methemoglobinemia, particularly in infants (blue baby syndrome). “In the 1940s, Comly first reported cases of cyanotic infants who received formula prepared with well water containing a high nitrate content. Based on the subsequent analyses of the infantile cases of methemoglobinemia, the US Environmental Protection Agency (EPA) set a Maximum Contaminant Level (MCL) for nitrate of 44 mg/L (equal to 10 mg/L nitrogen in nitrate). However, it is now thought that methemoglobinemia per se was not caused by nitrate itself, but by faecal bacteria that infected infants and produced NO in their gut. A recent report by Avery has argued that it is unlikely that nitrate causes methemoglobinemia without bacterial contamination, and also that the 40–50 mg/L limit on nitrate in drinking water is not necessary.” (Kobayashi, 2015)
However, there are now legal limits to the concentrations of nitrate and nitrite in both food and drinking water. The WHO showed that the Acceptable Daily Intake for humans (ADI) for nitrate and nitrite were 3.7 and 0.07 mg/kg body weight/day, respectively, which were based on the calculations from the doses of <500 mg of sodium nitrate/kg body weight that were harmless to rats and dogs. The international estimates of nitrate intake from food are 31–185 mg/day in Europe and 40–100 mg/day in the United States. However, the Ministry of Health, Labour and Welfare of Japan reported that the average intake of nitrate in the Japanese population is around 200–300 mg/day, which is one and a half times to two times the ADI. Furthermore, according to a report by Hord, in which the daily nitrate and nitrite intakes were calculated based on the variations using the vegetable and fruit components of the DASH (Dietary Approaches to Stop Hypertension) dietary pattern, the level easily exceeds 1,200 mg/day nitrate. This is more than five-fold higher than the WHO’s ADI of 3.7 mg nitrate/kg body weight/day, and more than two-fold the US Environmental Protection Agency’s level of 7.0 mg nitrate/kg body weight/day for a 60 kg individual. Furthermore, as indicated in Figure 2, approximately 25% of the ingested nitrate is secreted in saliva, and 20% of the secreted nitrate in the saliva is converted to nitrite by commensal bacteria on the tongue, indicating that about 5% of the originally ingested nitrate is swallowed into the stomach. Therefore, for a DASH diet containing 1200 mg nitrate, an individual would be expected to swallow approximately 45 mg of nitrite a day, which easily exceeds the ADI of nitrite. Therefore, a comprehensive reevaluation of the health effects of dietary sources of nitrate/nitrite might be required in the near future.” (Kobayashi, 2015)
– Other International Views on Nitrite/ Nitrate from Dietary Sources besides from the USA and Europe
The Food Standards Australia New Zealand and the European Food Safety Authority concluded that the major sources of estimated nitrate and nitrite exposure, across different population groups, were vegetables and fruits (including juices).Processed meats only accounted for 10% of total dietary exposure to nitrite in the European survey.Consumption and exposure to dietary nitrate and nitrite is not considered an ‘‘appreciable health and safety risk’’, according to the Australian agency. (Keller, 2017)
Given the established vasoprotective, performance-enhancing, blood pressure lowering effects of dietary nitrates in humans, specific recommendations to encourage plant-based, nitrate-rich foods may produce significant public health benefits. (Keller, 2017)
Is vitamin C and E the crucial link that saves bacon’s bacon?
Three important nitrosamines, namely N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA), and N-nitrosomorpholine (NMOR), are classified as probably carcinogenic to humans (Group 2B) by the International Agency for Research on Cancer (IARC) (IARC 2000). (Erkekoglu, 2010)
Intrinsic antioxidant systems, such as protective enzymatic antioxidants as well as antioxidants available in the human diet, provide an extensive array of protection that counteract potentially injurious oxidizing agents. (Erkekoglu, 2010)
It was found that antioxidants protected the cells against nitrite and nitrosamines. (Erkekoglu, 2010) Dietary antioxidants can be a saviour when exposure to dietary genotoxic/carcinogenic compounds is the case. (Erkekoglu, 2010)
Erkekoglu, 2010 confirmed the DNA damaging effect of nitrosamines as shown in other studies (Robichová et al. 2004b; Arranz et al. 2006; 2007; Garcia et al. 2008a; b). Additionally, they used sodium nitrite to show the genotoxic effects of nitrite alone. They showed that antioxidants supplementation was capable of reducing both tail intensity and tail moment in all of the nitrosamine treatments, particularly in NDMA. They proposed that this may be related to antioxidants’ reduction of CYP2E1 and CYP2A6. They write, “CYP2E1 is responsible for α-hydroxylation of N-alkylnitrosamines with short alkyl chain, whereas cyclic nitrosamines like NPYR, NPIP, and NMOR may be activated by CYP2A6 and by CYP2E1 to a lesser extent (Kamataki et al. 2002). Furthermore, inhibition of CYP450 enzymes may not be the only mechanism underlying the protection of antioxidants. Alternative mechanisms by antioxidants may be as follows: ROS scavenging capacity, the conversion of reactive compounds to less toxic and easily excreted compounds, alteration of cell proliferation, stimulation of DNA-repair induced by nitrosamines, induction of Phase II enzymes, and NAD(P): quinine oxidoreductase activity (Roomi et al. 1998; Chaudière and Ferrari-Iliou 1999; Gamet-Payrastre et al. 2000; Surh et al. 2001; Surh 2002).” (Erkekoglu, 2010)
Conclusion
It is obvious that the overwhelming weight of evidence is that nitrite is not the destructive chemical that it was made out to be and that the negative media frenzy is completely misguided, to put it mildly. The health benefits of nitrate, nitrite and nitric oxide are clear. An obvious path for improving the geneneral healt and nutritional status associated with cured meats is the incorporation of vegetable and plant matter into its formulation. The fact that nitrire-free curing may possibly never be achieved has been raised and warrants further investigation. The next two segments will focus on N-nitrosamines and why the protein myaglobin evolved in such a way that it wants to react with oxygen and nitric oxide.
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Sindelar, J.J.; Milkowski, A.L. Human safety controversies surrounding nitrate and nitrite in the diet. Nitric Oxide 2012, 26, 259–266.
Nitrite Cured Meat: It’s Fantastic but is it also Bad? By Eben van Tonder 15 February 2021
Introduction
I started my career in meat curing in 2008 when I founded the South African bacon brand Woody’s and the company Woody’s Consumer Brands with Oscar and Anton. I never imagined that the most exciting journey on earth would follow which I chronicled in Bacon & the Art of Living. I wanted to know as much as possible about the world of curing and the chemical, biological and bacterial reactions that fascinated me. One of the first books I consumed was Ronald Pegg and Fereidoon Shahidi’s work, Nitrite Curing of Meat: The N-Nitrosamine Problem and Nitrite Alternatives.
I delved into the matter with great interest. I discovered that nitrates are present in many vegetables, but they first need to change to nitrites through bacterial action before they change chemically into nitric oxide which then cures the meat. Nitrates are not very toxic, but once they change into nitrite and is fried, their reaction in the stomach is of particular concern.
As I learned more I discovered the importance of cured products in a world before refrigeration. They are extremely effective to protect us against pathogens, including the mother of all pathogens, Clostridium Botulinum. Its protective action extends into the age of refrigeration! Far from a villain chemical, it turns out that nitrite is an amazing compound that naturally occurs all around us and is, amongst others, formed in our mouths when we consume a wide variety of food including fruits and vegetables.
The question is now obvious. We know that adding nitrites to meat is doing a world of good in giving us safe food that lasts long without refrigeration and just happens to also taste delicious but are we causing more harm than good? Should we stop using it if we ingest far more nitrites from some vegetables than from cured meat? How do we evaluate a matter when scientists continually conclude any discussion on the matter with the words “more research on the topic is required?”
When did we realise that nitrite is not only beneficial but under certain conditions may be problematic? What exactly is the concern with its use? How did we end up using this? What physiological role does it play in humans? What benefits do we derive from ingesting it?
I will provide a brief overview. More than this, I use this as a landing page for material on the subject. Some of my consultancy work relates to exactly this topic and proprietary information is therefore restricted with password protection. Why “password” protected? Because the obvious next question is this: “Is there anything we can do to change it?” To manage the negative elements so that it is removed, and the product is wholly healthy! The answer is a resounding YES! But that is proprietary information! 🙂
A. How did we Realise there is a Problem?
What is the actual issue then and how did humans realise that there is a problem?
The Realization of Danger of Nitrites in Cured Meat and The Responses Since 1926
Nitrate was used as a curing agent for many thousands of years. The basic value initially related to the preventing of spoilage and in a world before refrigeration bacon soon became the staple meat source for the masses in a large part of the world. Curing with saltpetre, the common name for nitrate salts, takes about a month and apart from retarding spoilage, it imparts into meat a characteristic pinkish/ reddish colour and a very agreeable cured meat taste. In the 1800s a new method of curing was invented which reduced the time to cure meat considerably. It was called tank curing on account of the tanks that were used to cure the meat in or mild curing due to a reduced need for salt. It was invented in Ireland. When our understanding of chemistry and bacteriology matured, we realised the reason why tank curing sped meat curing up. For curing to take place nitrate (saltpetre) must first be converted to nitrite through bacterial action before it can be changed into nitric oxide which, we discovered, is the real curing molecule. So, nitrate (saltpetre) to nitrite curtesy of microorganisms (bacteria) and nitrite to nitric oxide through is a chemical reaction.
What was achieved through tank curing was that the step of bacteria changing nitrate into nitrite is cut out. Still, we do not add the nitrite directly. It is “added” through fermentation. The old brine is re-used and in doing so, the liquid is replete with nitrite that was already converted from nitrate. This, naturally, speeds the process up by cutting a step out. Before the late 1800’s curers did not have a clue what caused curing apart from saltpetre. They arrived at the process of tank curing through experimentation and observation without any inkling to microorganisms changing nitrate to nitrite.
The curing reaction was being unravelled by scientists late in the 1800s and early in the 1900s. As we learned that going from nitrite to nitric oxide is much quicker than going from nitrate first to nitrite and then to nitric oxide. We also realized that nitrite forms a salt with sodium to create sodium nitrite. Late in the 1800s and early in the 1900s sodium nitrite was being used in the dye industry and chemists stocked it because it became an important medication to treat some blood disorders. Butchers used it as the source of nitrite. It is easier and “cleaner” than the indirect creation of nitrite through fermentation (tank curing or mild curing). Sodium nitrite can be dissolved directly in a brine and will immediately start penetrating the meat and change to nitric oxide.
Tank curing soon lost its place as the quickest way to cure meat in favour of the direct addition of nitrites to curing brines. There was an issue with nitrites though in that most people at this time knew that nitrite was a potent toxin. Understandably, from very early, humans who did not “see” the conversion of nitrate to nitrites and did not understand that nitrites were in any event present in cured meat grappled with the concept of a toxic substance being introduced in food preparations.
During the First World War, curing brines came onto the market which included nitrites. The days of tank curing were numbered, and a controversy was born about how healthy this is. Several investigations were made into the matter. No sooner was the matter of the toxicity of nitrites settled through scientific investigation when another, far more dangerous issue came onto the scene in the 1970s of n-nitrosamines. Let’s run through the chronology of some of the key studies and some of the important ways that governments around the world responded to it.
We picked the investigations into this matter up in 1926 which looked at the matter of nitrite as a toxin. If it was simply a matter of concentration, it would be easily settled because we regularly use substances if food which, in too high dosages can harm or even kill us. Alcohol is a very good example. The way to mitigate the risk is to determine the “safe” levels and to ensure that producers use the appropriate dosages.
1926
A 1926 study by Kerr and co-workers was based on the general knowledge of nitrite’s toxicity and the publics very negative perceptions about it. In the report, they state that public health was the primary motivation behind the study. (Kerr, et al, 1926: 543) I quote from their report. “The first experiment involving the direct use of nitrite was formally authorized January 19, 1923, as a result of an application by one of the large establishments operating under Federal meat inspection. Before that time other requests for permission to experiment with nitrite had been received but had not been granted. The authorization for the first experiment specified that the whole process was to be conducted under the supervision of bureau inspectors and that after the curing had been completed the meat was to be held subject to laboratory examination and final judgment and would be destroyed if found to contain an excessive quantity of nitrites or if in any way it was unwholesome or unfit for food. This principle was rigidly adhered to throughout the experimental period, no meat being passed for food until its freedom from excessive nitrites had been assured, either by laboratory examination or through definite knowledge from previous examinations, that the amount of nitrite used in the process would not lead to the presence of an excessive quantity of nitrites in the meat. By “excessive” is meant a quantity of nitrite materially in excess of that which may be expected to be present in similar meats cured by the usual process.” (Kerr, et al, 1926: 543)
“The maximum nitrite content of any part of any nitrite-cured ham [was found to be] 200 parts per million. The hams cured with nitrate in the parallel experiment showed a maximum nitrite content of 45 parts per million.” (Kerr, et al, 1926: 543) The conclusion was that “hams and bacon could be successfully cured with sodium nitrite, and that nitrite curing need not involve the presence of as large quantities of nitrite in the product as sometimes are found in nitrate- cured meats.” (Kerr, et al, 1926: 545)
Related to the health concerns, the report concluded the following:
“The presence of nitrites in cured meats, was already sanctioned by the authoritative interpretation of the meat inspection and pure food and drugs acts sanctioning the use of saltpeter; as shown previously, meats cured with saltpeter and sodium nitrate regularly contain nitrites. (Wiley, H, et al, 1907) (Kerr, et al, 1926 : 550)
The residual nitrites found in the nitrite-cured meats were less than are commonly present in nitrate-cured meats. The maximum quantity of nitrite found in nitrite-cured meats, in particular, was much smaller than the maximum resulting from the use of nitrate.(Kerr, et al, 1926 : 550)
The nitrite-cured meats were also free from the residual nitrate which is commonly present in nitrate-cured meats. (Kerr, et al, 1926 : 550)
On the contrary, the more accurate control of the amount of “nitrite and the elimination of the residual or unconverted nitrate are definite advantages attained by the substitution. (Kerr, et al, 1926 : 550)
Following further studies, the Bureau set the legal limit for nitrites in finished products at 200 parts per million. (Bryan, N. S. et al, 2017: 86 – 90) Conventional wisdom that surfaced in the 1920s suggested that nitrate and nitrate should continue to be used in combination in curing brines (Davidson, M. P. et al; 2005: 171) as was the case with the Irish curing method or the tank curing concept of the previous century. Nitrite gives the immediate quick cure and nitrate acts as a reservoir for future nitrite and therefore prolongs the supply of nitrite and ensures a longer curing action. This concept remained with the curing industry until the matter of N-nitrosamines came up in the 1960s and ’70s, but remarkably enough, it persists in places like South Africa where to this day, using the two in combination is allowed for bacon. More about this later.
1931
The USDA progressed the ruling on nitrate and nitrites further in 1931 by stating that where both nitrites and nitrates are used, the limit for nitrite is 156 ppm nitrite and 1716 nitrate per 100lb of pumped, cured meat. (Bryan, N. S. et al, 2017: 86 – 90)
1960’s – N-Nitrosamine
Up to the 1960’s the limit on the ingoing level of nitrites was based on its toxicity. In the late 1950s an incident occurred in Norway involving fish meal that would become a health scare rivalled by few in the past. 1960’s researchers noticed that domestic animals fed on a fodder containing fish meal prepared from nitrite preserved herring were dying from liver failure. Researchers identified a group of compounds called nitrosamines which formed by a chemical reaction between the naturally occurring amines in the fish and sodium nitrite. Nitrosamines are potent cancer-causing agents and their potential presence in human foods became an immediate worry. An examination of a wide variety of foods treated with nitrites revealed that nitrosamines could indeed form under certain conditions. Fried bacon, especially when “done to a crisp,” consistently showed the presence of these compounds. (Schwarcz, J) In bacon, the issue is not nitrates, but the nitrites which form N-nitrosamines.
This fundamentally sharpened the focus of the work of Kerr and co-workers of the 1920s in response to the general toxicity of nitrites to the specific issue of N-nitrosamine formation. Reviews from 1986 and 1991 reported that “90% of the more than 300 N-nitroso compounds that have been tested in animal species including higher primates causes cancer, but no known case of human cancer has ever been shown to result from exposure to N-nitroso compounds.” However, despite this, there is an overwhelming body of indirect evidence that shows that a link exists and “the presence of N-nitroso compounds in food is regarded as an etiological risk factor. It has been suggested that 35% of all cancers in humans are dietary related and this fact should not surprise us. (Pegg and Shahidi, 2000)
Studies have been done showing that children who eat more than 12 nitrite-cured hot dogs per month have an increased risk of developing childhood leukaemia. The scientists responsible for the findings themselves cautioned that their findings are preliminary and that much more studies must be done. It may nevertheless be a good approach for parents to reduce their own intake of such products along with that of their children in cases where intake is high. (Pegg and Shahidi, 2000)
These studies must be balanced by the fact that an overwhelming amount of data has been emerging since the 1980s that indicate that N-nitroso compounds are formed in the human body. What is important is that we keep on doing further research on N-nitrosamines and the possible link to cancer in humans. Not enough evidence exists to draw final conclusions.
1970 – The response to the N-Nitrosamine scare.
Back in the 1970s, so grave was the concern of the US Government about the issue that in the early 1970’s they seriously considered a total ban on the use of nitrites in foods. (Pegg and Sahidi, 2000) The response to the N-nitrosamine issue was to go back to the approach that was implemented following the work of Kerr and co-workers in 1926.
The first response was to eliminate nitrate from almost all curing applications. The reason for this is to ensure greater control over the curing. Meat processors continued to use nitrate in their curing brines from 1920 until the 1970s. One survey from 1930 reported that 54% of curers in the US still used nitrate in their curing operations. 17% used sodium nitrite and 30% used a combination of nitrate and nitrite. By 1970, 50% of meat processors still used nitrate in canned, shelf stable. In 1974 all processors surveyed discontinued the use of nitrates in these products including in bacon, hams, canned sterile meats, and frankfurters. One of the reasons given for this change is the concern that nitrate is a precursor for N-nitrosamine formation during processing and after consumption. (Bryan, N. S. et al, 2017: 86 – 90)
The reason for the omission in bacon, in particular, is exactly the fact that the nitrates will, over time continue to be converted to nitrites which will result in continued higher levels of residual nitrites in the bacon compared to if only nitrite is used. The N-nitrosamine formation from nitrites is a reaction that can happen in the bacon during frying or in the stomach after it has been ingested. It will not happen from the more stable nitrates.
It has been discovered that nitrate continues to be present in cured meats. Just as the view that if nitrate was added, no nitrite is present in the brine as was the thinking in the time before the early and mid-1800s, in exactly the same way it is wrong to think that by adding nitrite only to meat, that no nitrate is present. “Moller (1971) found that approximately 20% of the nitrite added to a beef product was converted to nitrate within 2 hours of processing. Nitrate formation was noted during incubation before thermal processing, whereas after cooking only slight nitrate formation was detected. Upon storage, the conversion of nitrite to nitrate continued. Herring (1973) found a conspicuous level of nitrate in bacon formulated only from nitrite. As greater concentrations of nitrite were added to the belly, a higher content of nitrate was detected in the finished product. They reported that 30% of the nitrite added to bacon was converted to nitrate in less than one week and the level of nitrate continued to increase to approximately 40% of the added nitrite until about 10 weeks of storage. Moller (1974) suggested that when nitrite is added to meat, simultaneous oxidation of nitrite to nitrate and the ferrous ion of to the ferric ion of metMb occurs.” Adding ascorbate or erythorbate plays a key role in this conversion. (Pegg and Shahidi, 2000) The issue is not the nitrate itself, but the uncontrolled curing that results from nitrate and the higher residual nitrites.
Secondly, the levels of ingoing nitrite were reduced, especially for bacon. The efficacy of these measures stems from the fact that the rate of N-nitrosamine formation depends on the square of the concentration of residual nitrites in meats and by reducing the ingoing nitrite, the residual nitrite is automatically reduced and therefore the amount of N-nitrosamines. (Pegg and Sahidi, 2000) Legal limits were updated in 1970 in response to the nitrosamine paranoia. A problem with this approach is however that no matter by how much the ingoing nitrite is reduced, the precursors of N-Nitrosamine still remain in the meat being nitrites, amines, and amino acids.
An N-nitrosamine blocking agent was introduced in the form of sodium ascorbate or erythorbate. “There are several scavengers of nitrite which aid in suppressing N-nitrosation; ascorbic acid, sodium ascorbate, and erythorbate have been the preferred compound to date. Ascorbic acid inhibits N-Nitrosamine formation by reducing to give dehydroascorbic acid and NO. Because ascorbic acid competes with amines for , N-Nitrosamine formation is reduced. Ascorbate reacts with nitrite 240 times more rapidly than ascorbic acid and is, therefore, the preferred candidate of the two. (Pegg and Sahidi, 2000)
More detailed studies identified the following factors to influence the level of N-nitrosamine formation in cured meats. Residual and ingoing nitrite levels, preprocessing procedure and conditions, smoking, method of cooking, temperature and time, lean-to-adipose tissue ratio, and the presence of catalyst and/ or inhibitors. It must be noted that in general, levels of N-nitrosamines formation have been minuscule small, in the billions of parts per million, and sporadic. The one recurring problem item remained fried bacon. In its raw state bacon is generally free from N-nitrosamines “but after high-heat frying, N-nitrosamines are found almost invariably.” One report found that “all fried bacon samples and cooked-out bacon fats analyzed” were positive for N-nitrosamines although at reduced levels from earlier studies. (Pegg and Sahidi, 2000)
Regulatory efforts since 1920 have shown a marked decrease in the level of N-nitrosamines in cured meats, even though it is still not possible to eliminate it completely. “Cassens (1995) reported a marked decrease (approx 80%) in residual nitrite levels in of US prepared cured meat products from those determined 20 years earlier; levels in current retail products were 7 mg/kg from bacon.” This and similar results have been attributed to lower nitrite addition levels and the increased use of ascorbate or erythorbate. (Pegg and Sahidi, 2000)
Despite the actions of governments and the curing industry, consumer demand has grown over the years to eliminate nitrites in food. Evidence has started to emerge that links the prevalence of colon cancer, for example, not just to the use of nitrites but to the use of saltpetre or the far less toxic cousin of nitrite called nitrate. Much of the evidence is either anecdotal or indirect but it is sufficient to fuel public suspicion and legitimate industry concerns.
B. Can’t we just Remove the Nitrites?
What is clear from our survey above is that it is a technical and complex field. Can we not just remove the nitrites and sell nitrite-free bacon? When we talk about nitrite-free bacon, it is important to know exactly what we are talking about. The term can imply several things.
– Is the Problem Synthetic Nitrites Only (I.e. Sodium Nitrite Added Into the Brine)?
Is it that no synthesized nitrite must be used in the curing of the meat? Tank curing or fermented nitrate containing plant juices would then be an appropriate curing procedure. Celery and other plants are filled with nitrates which are part of plant nutrition, absorbed from the soil through the roots. Certain spice companies started using these plant extracts and then through a process of fermentation, allowed microorganisms to reduce the nitrite to nitrate like what was done in tank curing using old brine and they sold the plant extracts to be added to the meat as an ingredient. They called it a “natural curing agent” but in my opinion, they were actually deceiving the public. After the bacterial fermentation, the plant juices were now filled with nitrates. They cleverly circumvented the requirement to declare the use of nitrites in the curing process and in reality, nitrites were still present, now in usually much larger quantities as was the case using sodium nitrite.
– Is the Problem All Nitrites in the Brine and Meat, Including Either Sodium Nitrite or Nitrite that Formed Through Bacterial Action, Either through Reduction or Oxidation or Chemically and Irrespective of the Source?
Nitrite-free bacon can mean that no nitrites should be used in the curing process added directly or generated indirectly. Indirectly it can be generated through fermentation but there are other sources of nitrite which forms as a result of the decomposition of meat. In long-term curing, for example, the same colour, even a better taste and longer shelf life is achieved by the use of salt only. I mention this because it introduces a very important issue. For curing to take place, you don’t actually need nitrate or nitrite. You need nitrogen. The nitrogen must then react with oxygen to create nitric oxide (NO) which is a gas! Nitrate and nitrite are only the nitrogen source! Once Nitric Oxide is created, it must react with the meat proteins, myoglobin.
As the proteins of a dead animal or other constituents of meat are being broken down, nitrogen is made available and in long term curing, certain processes are involved and one of them is the combination of the nitrogen molecule, made available through decomposition, with an oxygen molecule and curing takes place if the overall destruction of the meat is managed through the removal of water which retards (even stops) the action of microorganisms and favours the effect of enzymes.
So, this can be done completely without any outside source of nitrogen but the process is very slow and there is no way that the world demand for cured meat will be satisfied through this. It will also be extremely expensive due to the weight loss involved in removing the moisture. No matter how you look at it, nitrogen must be accessed somehow, or it is not curing.
It is extremely important to know that curing is something that happens to the meat itself and it mimics a natural, biological process of nitric oxide being formed in our bodies. The meat protein in either its oxygenated state or with a nitric oxide molecule presents red. This is an extremely important concept to understand. Curing is a characteristic of meat itself and is a natural process. It is NOT the imposition upon the meat of a colouring agent. The fact that nitrogen is used in curing is completely consistent with natural biological processes. Even the reduction and interaction of nitrate and nitrite, including the chemical reduction to nitric oxide, is a biological process, essential to life!
I give one example from a review article by Shiva (2013). I anticipate that very soon consumers may demand food with high nitrate (NO3-) in a swing in perceptions of these molecules which will in all likelihood be driven by people who regularly work out. Shiva summarizes this work as follows. “Nitrite dependent inhibition of ccox also potentially regulates responses to physiological hypoxia (the absence of enough oxygen in the muscles), such as that present in the muscle during exercise. Larsen and colleagues recently demonstrated that ingestion of NO3- (nitrate) decreased whole-body oxygen consumption during exercise without changing maximal attainable work rate in human subjects.” Directly as a result of this work, several booster supplements are currently on the market and sold in gyms and health shops around the world containing nitrates.
Shiva continues, “This increase in exercise efficiency, which was associated with augmented plasma NO2- levels, has now been corroborated by a number of studies in various exercise models. While the underlying mechanism of this beneficial effect is not completely elucidated, a decrease in the rate of oxygen consumption due to proton leak and state 4 respiration in the skeletal muscle of subjects receiving NO3- was reported.” (Shiva, 2013)
Right there, the entire matter is resolved and in a few short years, the public will demand more nitrates in meat (and by implication, nitrite also)! 🙂 🙂
Furthermore, not only is the reaction of nitrite to nitric oxide not foreign in our physiology, the reaction of nitric oxide with myoglobin is an extremely important physiological reaction that is mimicked in curing. Jens Moller and Leif Skibsted write that “Nitrosylmyoglobin (MbFeIINO), the NO complex of iron (II) myoglobin, as formed in meat products, has now also been observed in vivo in rats. MbFeIINO thus seems important in controlling radical processes associated with oxidation”. (Møller and Skibsted, 2002)
The issue is that our best available source of nitrogen is through nitrite and nitrite itself but is both beneficial and problematic at the same time.
The fact that the reaction of oxygen (O2) and Nitric Oxide are both matters that all butchers work with daily is important. None of these reactions is “unnatural!” This is seen in the colour of fresh meat and cured meat. I dedicated a chapter to it in Bacon & the Art of Living, called Fresh Meat Colour vs Cooked Cured Colour.
I plan to do much more work about the physiological reason why nitric oxide fits onto the colouring site of a protein apart from the short quotes above, but I will deal with this separately and update this section with a link reference.
– If the Meat itself Does Not Change Colour (Curing), is the use of External Colourant Permitted/ Desirable?
There is another way of achieving a red colour in meat which we alluded to and that is through an artificial process that involves the use of an external colourant. Legally there are colourants that are allowed in meat, but how will consumer groups respond to this? This is not something natural and inherently part of meat itself. It is an external colourant that is brought to bear upon the meat matrix. This is even more objectionable to some than nitrite and the extreme objection against it goes back to the start of the meat trade where butchers used to disguise old and sometimes putrid meat as fresh by colouring it with an external colourant.
– Is the Real Issue Actually Residual Nitrite That We Must Eliminate? (I.e., Not Ingoing Nitrite but Nitrite Left in Meat After Curing)
Another possible meaning of nitrite-free bacon refers not to the fact that nitrite was somewhere involved in the supply of the nitrogen source to form nitric oxide, but the real meaning may refer to the question of whether any nitrite is left in the product when the consumer fries it in the pan. It is after all not the initial source of the nitrogen atom, which is the real issue, but how much nitrite is left after the meat has been cured. This is what is referred to as residue nitrite. The other question which goes hand in hand with this is to what degree can the consumer be guaranteed that no appreciable amount of nitrite is left in the product he buys?
– Is The Objective to Eliminate All Manipulation of Colour (Natural or Artificial) and Resign Ourselves to Selling Brown Bacon and Hams (uncured, salted only)?
A final solution for some is to simply omit accessing nitrogen in any shape or form altogether and not be concerned about the brownish colour that develops. I have over a few years followed the work of a New Zealand company, interestingly enough also called Woody’s who follow this approach and I am amazed at the success they have had with their brand positioning. Good old strict hygiene is used to sort shelf-life issues out and they educate their customers that the browner bacon is actually healthier bacon. The brown bacon they sell becomes a source of comfort for their clients. If this is advisable as a universal approach to bacon or ham is debatable in a world where not everybody shares the strict attention to detail of this company, but I applaud them for their honesty and the practical way in which they have dealt with this thorny issue (see Woody’s Free Range Farm) In the end, I feel much of the problems are self-inflicted in a world where bacon flitches are no longer wrapped in cloth, palletized and shipped any longer.
By William James Topley – This image is available from Library and Archives Canada under the reproduction reference number PA-026092 and under the MIKAN ID number 3424485
How to Explain it?
As you can see from this short overview, the matter is not simple but the fact that there is an issue to address is clear. For myself, I am satisfied that in the minuscule levels that nitrite is used and remains present in bacon and hams, these products are completely safe to eat. The consumer is, however, also not wrong to be concerned about the matter. The problem is that the explanation above is already so technical – who can follow this? Let alone a dissertation by Dr Sebranek or Dr Møller, two of the world authorities on the subject. If anybody must understand what they are saying before one can decide which bacon is healthy and not and which brine to use or not, only a handful of people will ever make a meaningful determination on the matter. This business of reduction and oxidation, bacterial, enzymatic reactions are all very confusing for people without an advanced degree in chemistry, like me. The only way that I could make any sense of it was to follow the story right from the beginning. As it unfolded. And what a story it turned out to be!
C. Review: How did we get here?
I will tell the story, at least the parts that are pertinent to the discussion about nitrite, from a series of articles I did on the subject over a few years and from extracts of a book I wrote about the history of bacon called Bacon & the Art of Living. One article where I deal with the full sweep of its history is Bacon Curing – a Historical Review.
Before we jump into the detail, let’s establish a timeline. Broadly speaking the development of bacon curing to where we are with the direct addition of nitrite to curing brine can be divided into the following timeline.
The Prehistory of Bacon Curing experimenting with various salts (sodium chloride, sal ammoniac, nitrate also called saltpetre) From antiquity to the end of the 1500s.
Saltpetre gained popularity as it becomes widely available as a vitalizer, an ingredient in gunpowder and as medication. 1600 to 1800.
William Oake invented Tank Curing/ Mild Curing around 1832 (aged 25) – an Indirect Addition of Nitrite to Curing Brines.
Dr. Ed Polenski’s Article on Nitrite in saltpetre brines, 1891.
The academic work of German and English researchers identifying Nitrate and Nitric Oxide as the curing agents. Notwang (1892), Lehmann (1899), Kiskalt (1899), Haldane (1901).
The work of Ladislav Nachmullner and the first curing brine containing sodium nitrite (1915).
The Impact of the First and Second World War in changing the indirect use of Nitrites to the direct addition of nitrites to curing brines.
The Griffith Laboratories as evangelists of the direct addition of nitrites to curing brines. Prague Salt (1925).
“Houston, we have a problem!” The n-nitrosamine problem and the response of the curing industry and world governments, late 1950s.
Must we Remove Nitrite from Food or Manage it?
D. Why do we use it at all?
Its anti-microbial ability now becomes important, especially as it relates to C Botulinum. Nitrite as a key hurdle in botulinum prevention remains relevant. I looked at the most important microorganism in a 2015 article, Clostridium Botulinum – the priority organism
The Anti-Microbial Efficacy of Nitrite
In 2015 I had the privilege to interact with Dr R. Bruce Tompkin on the issue of the antimicrobial efficacy of nitrate and nitrite. Dr Tompkin was one of the founders of the HACCP system. We had some correspondence about the possibility of replacing nitrite as a hurdle and his insights are still helpful to this day. For this, I will be eternally grateful. It was written before I discovered that tank curing came from Ireland and there are other sections where my understanding evolved. I nevertheless share it with you as I wrote five years ago. I am thankful for experts from around the world who continue taking the time to give input not just on the matter of nitrite replaces, but on a wide array of meat and processing-related subjects. I can honestly say that if you do not know in our trade you do not want to know! (or you have been so busy that there was no time to find out!) Which I fully understand!!
I have no doubt that this matter can be resolved scientifically. In terms of marketing, this can be done in a way that the consumer will be fully in-step, all the way and is taken along, not left behind or feel that half-baked ideas are thrust down his/her throat. This work is important, not just for the uncompromising drive to better and healthier food, but for the overall quest to be better in every way! To offer safe and delicious food should be the desire of every food producer on earth. Anything less both in terms of taste, quality, and safety is a crime! In this work, I can end with a quote from no finer man than Nelson Mandela who said that “what counts in life is not the mere fact that we lived. It is what difference we have made to the lives of others that will determine the significance of the life we lead!”
References
Jens K. S. Møller and Leif H. Skibsted. 2002. Nitric Oxide and Myoglobins. Chemical Reviews 2002102 (4), 1167-1178DOI: 10.1021/cr000078y
to the ferric ion of metMb occurs.” Adding ascorbate or erythorbate plays a key role in this conversion. (Pegg and Shahidi, 2000) The issue is not the nitrate itself, but the uncontrolled curing that results from nitrate and the higher residual nitrites.
to give dehydroascorbic acid and NO. Because ascorbic acid competes with amines for 
