This doesn’t look good for meat eaters. The chemical N-Glycolylneuraminic acid (Neu5Gc) is found in most mammal tissue except for our own. We lost the ability to manufacture it “two to three millions of years ago, which occurred just before the emergence of the genus Homo.” Because we don’t make it, our body sees it as foreign if we eat it. That triggers an immune reaction. Chronic exposure to Neu5Gc leads to chronic inflammation which is known to promote cancer … and did in this new study.
Study: A Red Meat-Derived Glycan Promotes Inflammation And Cancer Progression, PNAS, 25 December 2014
Press Release: Sugar Molecule Links Red Meat Consumption and Elevated Cancer Risk in Mice, UC San Diego Health System, 29 December 2014
We present an unusual mechanism for the well-known association between red meat consumption and carcinoma risk involving the nonhuman sialic acid N-glycolylneuraminic acid (Neu5Gc). We first evaluate the Neu5Gc content of various foods to show that red meats are particularly rich in orally bioavailable Neu5Gc and then investigate human-like Neu5Gc-deficient mice fed this form of Neu5Gc. When such mice were challenged with anti-Neu5Gc antibodies, they developed evidence of systemic inflammation. Long-term exposure to this combination resulted in a significantly higher incidence of carcinomas (five-fold increase) and an association with Neu5Gc accumulation in the tumors. Similar mechanisms may contribute to the association of red meat consumption with other diseases, such as atherosclerosis and type 2 diabetes, which are also exacerbated by inflammation.
The study did not involve exposure to carcinogens or artificially inducing cancers, further implicating Neu5Gc as a key link between red meat consumption and cancer.
The Telegraph covered it and said this:
A study published by Harvard University in June suggested that a diet high in red meat raised the risk of breast cancer for women by 22%.
In 2005 a study found those who regularly ate 5.6oz (160g) of red meat a day had one third higher risk of bowel cancer.
– Red Meat Triggers Toxic Immune Reaction Which Causes Cancer, Scientists Find, The Telegraph, 1 January 2015
I think a five-fold increase in tumors, when the mice weren’t even exposed to a carcinogen, is considerable. (Besides red meat, Neu5Gc is also found in dairy products and seafood.)