Glycobiology, Red Meat and Cancer

Larry A. Law

A recent study on sialic acid (a sugar) shines a bright light on an established risk factor for cancer. Scientists and doctors have known long-term consumption of red meat (beef, pork and lamb) is highly correlated to cancer. Researchers have looked for specific mechanisms that would cause human carcinomas. Grilling red meat was thought to create DNA damage due to mutagens which are chemicals that mutate DNA. But the theory doesn’t pan out. Grilling poultry and fish generates the same mutagens but fish and poultry are not associated with an increased risk of cancer. Red meat affects humans but does not

cause cancer in carnivores so there must be some other kind of mechanism that targets only humans. Researchers studying this particular glycan (the sugar called sialic acid that we teach about in our class) seem to have stumbled upon the answer. If it has been awhile since you have  seen our class, click here to register for a free webinar.

​The researchers centered their efforts on a non-human form of sialic acid (Neu5Gc) that is present in significant quantities in red meat but not poultry or fish (except caviar). The human version of this sialic acid sugar is Neu5Ac or N-acetylneuraminic acid. Researchers were able to demonstrate that while the non-human glycan is not produced by humans it does show up on human epithelial cell surface sugar structures (glycoproteins). Epithelial cells line our throat and intestinal tract. It is especially common in cancerous tissue. (Varki A (2010) Colloquium paper: Uniquely human evolution of sialic acid genetics and biology. Proc Natl Acad Sci USA 107(Suppl 2):8929-8946.)

The only way this non-human sialic acid could be embedded on human glycoproteins (sugar antennas) is through diet. Red meat contains this non-human version of the sialic acid sugar. If we eat a lot of red meat, the glycoproteins on our cells can have this non-human form of sialic acid incorporated within them. The non-human sialic acid is what causes inflammation and is linked to cancer. The human form of sialic acid does not cause this type of problem. It is anti-inflammatory and supports the immune system.

​Since epithelial (surface) cells are replaced every few days, eating red meat sparingly gives the body a chance to replace this non-human form of sialic acid accumulated from a diet high in red meat with the human form. This gives the body a chance to rest from inflammation and disease creation. A constant diet of red meat gives the body no time to heal.

Metabolic incorporation (glycosylation) of dietary Neu5Gc into human tissue “makes this glycan the first example of a xeno-autoantigen which can react with circulating anti-Neu5Gc antibodies (xeno-antibodies). The resulting antigen-antibody interaction is hypothesized to promote chronic inflammation or ‘xenosialitis’ which would contribute to carcinogenesis or to other diseases exacerbated by chronic inflammation…it appears that glycosidically bound Neu5Gc is the dietary source that is bioavailable for tissue incorporation and not the free monosaccharide.” (Samraj, Annie, et al. 2014. A Red Meat-derived Glycan Promotes Inflammation and Cancer Progression. PNAS January 13, 2015 Vol 112, no. 2)

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This research explains why eating too much red meat is linked to cancer. Many healthy diets either eliminate red meat or allow it only sparingly. The wisdom of this advice has just been verified and validated by the field of glycobiology, the science that studies sugar!

Vegetables, fruit, fish, shellfish, chicken, turkey, eggs, and butter do not contain the non-human sialic acid. Caviar, beef, cheese from goat’s milk or cow's milk, pork, bison, and lamb (in descending order of amount) contain the non-human version of sialic acid. These foods should be minimized.
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The science of nutritional glycobiology continues to evolve. Why disease occurs is tied to the sugar code of life. We can make informed choices about how much meat we should eat because of this research.

Again, feel free to register for a class webinar if it has been awhile since you have taken our class. It will give you a good foundation on the critical nature of sugar-nutrients (NOT the kind of sugar we are getting way too much of in our diets today!). Understanding the role of good sugars for proper immune function can make all the difference for the quality of our lives. Supplementing them is the only way to get enough in today’s world since they are gravely missing from our “whole”, real foods. If you would like our opinion for safe and trusted options for supplementing go to GRMVetted.org and request it.