Discovering Aloys L. Tappel

Discovering Aloys L. Tappel

Eben van Tonder : Somewhere in 2019


Some time during 2019, my wife asked me one night why too much red meat is bad for you. The man who first saw this was not a physician but a very gifted food scientist, Al Tappel.

– Oxidative Stress

In his groundbreaking 2007 publication, Heme of consumed red meat can act as a catalyst of oxidative damage and could initiate colon, breast and prostrate cancers heart disease and other diseases, he noted that “dietary epidemiological studies indicate correlations between the consumption of red meat and/or processed meat and cancer of the colon, rectum, stomach, pancreas, bladder, endometrium and ovaries, prostate, breast and lung, heart disease, rheumatoid arthritis, type 2 diabetes and Alzheimer’s disease. The correlation of all these major diseases with dietary red meat indicates the presence of factors in red meat that damage biological components.”

Tappel’s hypothesis focused on “the biochemistry of heme compounds and their oxidative processes.” He writes that “raw red meat contains high levels of oxymyoglobin and deoxymyoglobin and oxyhemoglobin and deoxyhemoglobin and cytochromes in muscle and other tissues. Cooked and processed meat contain hemichromes and hemochromes. After being eaten heme proteins are hydrolyzed to amino acids and peptides and the heme group which is coordinated with strong ligands. The iron of heme coordinates to the sulfur, nitrogen or oxygen of amino acids and peptides and other biological components. The coordinated heme groups are absorbed and transported by the blood to every organ and tissue. Free and coordinated heme preferentially catalyze oxidative reactions. Heme catalyzed oxidations can damage lipids, proteins, DNA and other nucleic acids and various components of biological systems. Heme catalysis with hydroperoxide intermediates can initiate further oxidations some of which would result in oxidative chain reactions.”

“Biochemical and tissue free radical damage caused by heme catalyzed oxidations is similar to that resulting from ionizing radiation. Oxidative biochemical damage is widespread in diseases. It is apparent that decreasing the amount of dietary red meat will limit the level of oxidative catalysts in the tissues of the body.”

– Modulation Through Antioxidants

On the one hand, Tappel sounded the alarm and on the other hand he investigated the resolution of the problem. He writes that “increasing consumption of vegetables and fruits elevates the levels of antioxidative components, for example, selenium, vitamin E, vitamin C, lycopene, cysteine-glutathione and various phytochemicals.” He researched dietary antioxidants as the modulation of the adverse effects of red meat.

When Tappel started his work, the detrimental processes of heme catalysis of oxidative damage which he hypothesized were not well recognized. He became the man who dedicated his career to understanding it and focusing on antioxidants.

Tappel’s research showed that augmentation of the natural antioxidant defense systems through exogenous antioxidants provided by fruits and vegetables can favorably prevent or modulate biological damage such as oxidative stress initiated by iron or heme iron entities

Following on and building on the work of Tappel many studies have been done which illustrated the relationship between fruit and vegetable protection against chronic diseases, a driving force for recommendations that half of your plate should be fruits and vegetables.

Omaye (2019) writes that following Tappel, it was shown that “fruits and vegetables are usually low in energy density and good sources of fiber, vitamins, and minerals. They are also usually good sources of a variety of phytochemicals, including polyphenolics and other bioactive substances. It is agreed that fruit and vegetables provide antioxidants and that plant-based foods introduce more antioxidants into human diets than non-plant foods and likely defend against oxidative stress. Therefore, augmentation of the natural antioxidant defense systems through exogenous antioxidants provided by fruits and vegetables can favorably prevent or modulate such biological damage, including oxidative stress initiated by iron or heme iron entities. Likewise, the benefits of supplementing diets with polyphenolic nutraceuticals would be through the efficacious modulation of the antioxidant capacity of microbiota.

I realised that much of my work would be focusing on the inclusion of antioxidants from fruit, and vegetables and forever I will stand on the shoulders of this remarkable man. One of my first tasks will be to review the work he has done in this regard.

By way of honouring him for his phenomenal contribution to food science and humanity at large I decided to give a short overview of his life and work. Davidsen Enterprise did and excellent obituary for him and I quote it here in full. It touches many of the highlights of a remarkable mans career and personal life.

The Remarkable Life of Al Tappel

Nov. 21, 1926 — Nov. 25, 2017

Aloys L. Tappel, 91, of Davis passed away on Nov. 25, 2017, at his home with loving family members and a caregiver at his bedside, from pneumonia, after living with Parkinson’s Disease for many years.

Al was born on Nov. 21, 1926, in a house in St. Louis, to Aloys and Julian Tappel. Al developed an early interest in science while he was educated at parochial schools and he graduated from St. Louis University High School. He received his bachelor’s degree in Chemical Engineering at Iowa State University. Al received his Ph.D. In Biochemistry under Paul Boyer, later a Nobel laureate, and Walt Lundberg of the Hormel Institute and the University of Minnesota.

Al met his future wife, Ardelle Amber Fish, in lipids class on the St. Paul campus of the University of Minnesota. They became acquainted on long walks after lunch. Al and Ardelle married on May 26, 1951, in the Chapel of the Cathedral in St. Paul, Minnesota.

When the Department of Food Science and Technology moved from UC Berkeley to UC Davis, Al was interviewed and hired by Emil Mrak, then the chairman of the Department of Food Science and Technology. Al and Ardelle moved to Davis in 1951, where Al joined the Department of Food Science and Technology as an instructor until 1953 when he was appointed assistant professor in 1953. Appointments to follow, all in the department of food science and technology: associate professor, 1957-1961; professor, 1961-1994; and professor emeritus from 1994 onward.

During Al’s 50 years on the faculty, he taught food biochemistry for graduate students and food analysis for undergraduates. Al’s main activity was research on food biochemistry, nutrition and related subjects in collaboration with graduate students, postdoctoral scientists and visiting scientists. Al’s research resulted in more than 450 peer-reviewed scientific publications in a broad range of scientific journals. Al collaborated with 13 Ph.D. students, 34 post-Ph.D.s and 58 visiting scientists and faculty members.

Al coined the scientific term “peroxidation” in order to distinguish the oxidative reactions involving peroxide (which are deleterious to tissue) from the oxidative reactions involved in the benign metabolic utilization of lipids for energy. Al conducted pioneering research on the peroxidation of lipids in vivo and its effects on cellular damage.

He was the first to demonstrate that combinations of antioxidants are more effective in preventing peroxidation than each acting alone. A wide spectrum of blended compounds offers twice as much protection as single antioxidants. The synergistic effect provides anti-cancer protection. Al also worked on other topics including lysosomal enzymes, biological effects of selenium, and new analytical methods in biochemisty.

Some of the 13 awards Al received included the 1965 Guggenheim Fellowship, 1973 Borden Award from American Institute of Nutrition, 1991 Award of the Agricultural and Food Chemistry Division of the American Chemical Society, 1992 Supelco American Oil Chemists Society Research Award, 1995 Alton E. Bailey Medal of the American Chemists Society, 1995 Chang Award of the American Oil Chemists Society, 1997 The Oxygen Club of California Award, and also 1997 the Nicholas Appert Award.

Al enjoyed spending time with his family, reading, camping, hiking, backpacking, cross-country skiing, and traveling in his RV with his wife. Al and (Ardelle) Amber were very close and loving in their relationship.

Al is survived by his loving wife of 66 years, (Ardelle) Amber; daughters Susan Tappel (Norman) of Davis, Mary Tappel (John) of Sacramento, Cathy Steele Tappel (Marc) of Vancouver, Wash., and Liz Brownfield of San Jose; sons Steve Tappel of Davis and Paul Tappel (Kerry) of Brier, Wash.; 13 grandchildren; and one great-grandchild. Al is also survived by his brother Ed Tappel of Cincinnati, and his brother-in-law Ron Fish (Belva) of Shafer, Minnesota.

The family wishes to thank Al’s caregivers in his final years: Latileta Soqonatabua, Sala Rokomatu and Vinnie Vasuikoro.”

Video Link

Excellent Video where Tappel is interviewed: Interview with Al Tappal


Tappel A. Heme of consumed red meat can act as a catalyst of oxidative damage and could initiate colon, breast and prostate cancers, heart disease and other diseases. Med Hypotheses. 2007;68(3):562-564. doi:10.1016/j.mehy.2006.08.025