Deep Frying Meat: Elements of a Comprehensive Food Safety and Nutritional Debate in Ancient West Africa Eben van Tonder 5 August 2023
Introduction
I am reading Ben-Dor (2021) to understand the changes in human diets that occurred over millennia. They concluded that the evolutionary lineage of hominins including modern humans (Homo sapiens) and their extinct close relatives in the food chain that most probably led to modern humans, evolved from a low base to a high, carnivorous position during the Pleistocene which is the period that occurred approximately 2.58 million years ago and lasted until around 11,700 years ago. (Ben-Dor, 2021)
What he said about the key role of fat in our diets caught my attention. From my studies on nutrition in Southern Africa, I noted that consuming very lean game meat leads to illness and for this reason, the ancients of the region mixed fat from fat-tale sheep with game meat when they consumed it. So, I am well aware that a diet devoid of fat is not nutritious.
I want to place the discussion within a West African context. I encountered a society in Nigeria that is accustomed to cooking their meat and then deep frying it. This, in itself, is an excellent preservation technique which became the method of choice for people in West Africa who required a “mid-term” preservation of a few days, similar to our refrigeration of meat at a temperature of between 1 and 6 deg C. When we refrigerate fresh meat, it lasts a few days at best. Cooking the meat eliminated any possible microbial contamination in the meat and deep-frying it would seal the meat, creating a barrier around it which would be effective for a few days at best.
Long-term preservation relied on sun drying the meat which was interestingly augmented with coating it with various nut meals (what is left after the oil has been extracted). Such coating had many benefits which included the rich nutritional value of the nuts, augmenting that of the meat, dietary fibres with its benefit to human health as well as residue oil that was not extracted with rudimentary extraction techniques, contributing to “sealing” the meat. Adding the nut meal contributed to an exquisite organoleptic experience when softer meat is mixed with harder crunchy nuts. So, plant oils serve a key function in mid-term preservation (a few days) and long-term preservation without refrigeration and freezers.
The Ben-Dor study altered me to a more subtle but vitally important function of deep frying fresh/cooked meat in vegetable oil and coating meat before it is sun-dried with nut meal. By doing these, we add fat to the diet.
Lagos is situated in a climate not suitable for cattle herding. Traditionally and still today cattle come from the north which in turn are fed from the lucrative cattle regions of Chad and Niger. Today the cattle are taken from large northern cattle markets by truck to Lagos, but traditionally the animals walked to Lagos on the hoof. This means that a large part of Nigerians is accustomed to lean meat and very lean meat.
Deep-Frying Vegetable Oil – General Considerations
Deep frying the meat is to add fat to the lean meat and enhances its nutritional value many times over. Before we look at the benefits, let’s pause a moment to consider some negative results.
a. When vegetable oils are heated to high temperatures during frying, they can undergo chemical changes, leading to the formation of harmful compounds. One of these compounds is acrylamide, which forms when starchy foods are fried at high temperatures. Acrylamide is a potential carcinogen and has been linked to an increased risk of cancer in animal studies.
b. Heating vegetable oils to high temperatures can cause them to undergo oxidation, which leads to the production of free radicals. Free radicals are highly reactive molecules that can damage cells and contribute to various health issues, including inflammation and oxidative stress.
c. Frying vegetables in oil can result in some loss of heat-sensitive nutrients, such as certain vitamins and antioxidants. The high heat can break down these nutrients, reducing the overall nutritional value of the food.d. Frying adds extra calories to the food, as the oil is absorbed during the cooking process. This can contribute to weight gain and obesity if fried foods are consumed in excess.
e. Some vegetable oils, such as those high in omega-6 fatty acids (e.g., corn, soybean, and sunflower oil), can promote inflammation when consumed in large amounts. An imbalanced intake of omega-6 fatty acids relative to omega-3 fatty acids may be linked to an increased risk of heart disease.
f. Repeatedly heating vegetable oils for frying can lead to the formation of trans fats, which are unhealthy fats associated with an increased risk of heart disease.
Benefits of Deep Frying Meat in Palm Oil or Peanut Oil.
In Nigeria, the oil of choice for deep-frying meat would have been and still is either palm oil or peanut oil.
1. Both palm oil and peanut oil have a high smoke point of about 450°F (232°C), making them suitable for deep frying at high temperatures without compromising the oil’s stability.
2. Peanut oil has a mild and neutral flavour, allowing the natural taste of the fried food to shine through without any strong aftertaste. Palm oil, on the other hand, has a distinct nutty and earthy flavour, which can enhance the taste of fried foods, providing a unique and rich culinary experience.
3. Palm oil contains a mix of saturated and unsaturated fats, as well as vitamin E and carotenoids (antioxidants). While it is calorie-dense, it does not contain trans fats, which are harmful to health. The presence of antioxidants can also contribute to reducing oxidative stress in the body.
4. Peanut oil is high in monounsaturated fats, which have been associated with various health benefits, including improved heart health and cholesterol levels.
5. Like all oils, palm oil and peanut oil are calorie-dense and would contribute considerably to nutrition.
The benefits of adding fat to lean meat would have been observed and I can see how the practice of deep-frying meat became popular, not only because of the preserving properties, but also for nutritional benefits which would have been observed from the earliest times.
Fat and Diet
Ben-Dor (2021) is doing an evaluation of the evidence that indicates high meat consumption of early humans which tapered off slightly with the advent of the agricultural revolution. Within this discussion, he considers our adaptation to high meat/ fat consumption genetically and in terms of our metabolism.
He writes, “Swain-Lenz et al. (2019) performed comparative analyses of the adipose chromatin landscape in humans, chimpanzees, and rhesus macaques.” The adipose chromatin landscape refers to the overall organization and structure of chromatin within adipose tissue cells. Chromatin is a complex of DNA, RNA, and proteins found in the nucleus of cells. It plays a crucial role in regulating gene expression, determining which genes are active or inactive, and controlling various cellular processes.
Adipose tissue, commonly known as body fat, is a specialized connective tissue composed of adipocytes (fat cells) surrounded by a stromal-vascular fraction that includes preadipocytes, endothelial cells, fibroblasts, and immune cells. The chromatin landscape within adipocytes and the surrounding cells plays a vital role in adipose tissue development, function, and metabolism. Understanding the adipose chromatin landscape is crucial for gaining insights into the molecular mechanisms underlying adipose tissue development, obesity, and metabolic disorders.
Swain-Lenz et al. (2019), conclude “that their findings reflect differences in the adapted diets of humans and chimpanzees. They (p. 2004) write: “Taken together, these results suggest that humans shut down regions of the genome to accommodate a high-fat diet while chimpanzees open regions of the genome to accommodate a high sugar diet.”
“Speth (1989) hypothesized that humans eating an animal-based diet would display a mandatory (obligatory) requirement for significant fat amounts because they are limited in the amount of protein they can metabolize to energy. Dietary fat is also a macronutrient with priority storage within subcutaneous fat stores; this agrees with assumptions of adaptation to higher fat consumption.”
“The ability to finely tune fat-burning is a prominent feature of human metabolism (Akkaoui et al., 2009; Mattson et al., 2018). The lipase enzyme plays a dominant role in fat storage and metabolism. Comparing the pace of genetic changes between humans and other primates, Vining and Nunn (2016) found that lipase production underwent substantial evolution in humans.”
“Weyer and Pääbo (2016) found some indication of differences in both the regulation and activity of pancreatic lipase in modern humans compared with Neandertals and Denisovans. Given that Neandertals probably consumed a diet higher in meat and fat than anatomically modern humans, the latter was possibly adapting to lower fat consumption. However, these changes are also found in present-day humans, but there is no indication of how early they occurred in H. sapiens evolution. They could have resulted from a shift to a diet higher in plants in the period leading up to the adoption of agriculture, in which a marked increase in genetic changes is evident (Hawks et al., 2007). Additionally, storing larger fat reserves is a derived trait in humans, regardless of nutritional source (Pontzer, 2015). Thus, changes in fat metabolization capacity may, in part, be associated with metabolizing stored fat.
“In humans, eating predominantly animal foods, especially fatty animal foods, promote nutritional ketosis. This pattern provides generous amounts of bioavailable essential micronutrients with crucial roles in encephalization (the evolutionary process of an increase in brain size relative to body size), such as zinc, heme iron, vitamin B12, and long-chain omega-3 and 6 fatty acids (DHA and arachidonic acid, respectively) (Cunnane & Crawford, 2003). Infants’ brains meet all of their cholesterol needs in situ, with 30% to 70% of the required carbons being supplied by ketone bodies (Cunnane et al., 1999). Recently, nutritional ketosis has gained popularity as a possible therapeutic tool in many pathologies, such as diabetes, Alzheimer’s disease, and cancer (Ludwig, 2019).
Conclusion
Understanding the value of fat in the human diet and the fact that the best food source, being meat, is excessively lean in Nigeria due to the supply network that exists in this region since antiquity, one recognizes the nutritional benefits of deep-frying meat. The value as a preservative is clear, but identifying the nutritional value underscores the fact that a food safety and nutritional debate existed in West Africa since antiquity that resulted in a comprehensive food system in the region which is poorly understood by the West. Understanding this comprehensive system leads to alternative options for handling matters of food safety and nutrition compared to traditional Western methodologies.
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References
Ben-Dor, M., Sirtoli, R., Barkai, R.. (2021) The evolution of the human trophic level during the Pleistocene, First published: 05 March 2021 https://doi.org/10.1002/ajpa.24247
Photo from: https://cookpad.com/ke/recipes/5581531-deep-fried-beef