NMU 138 – Red Meat Neu5Gc protein and Heart Attacks
Nutrition / Natural Medicine Update No 138 (August 8, 2019)
with Dr. James Meschino
Topic: Red Meat Increases Heart Attack Risk in Humans Due to Genetic Defect we Inherited from Our Ancestors
Source: Proceedings of the National Academy of Sciences (July 22, 2019)
I have an interesting story to tell you today about human evolution, red meat consumption, and the risk of a heart attack. Let’s start with the part of human evolution. As it turns out approximately a couple of million years ago our ancestors lost the ability to synthesize a protein called the Neu5Gc (N-glycolylneuraminic acid) due to a gene mutation in the CMAH gene. We think it’s because humans who lacked this protein were, at the time, protected against the type of malaria that was present during that period, and so these individuals were able to survive and they passed this gene mutation on to the future generations, including us. Today’s malarial disease affects a different target within our red blood cells, so we are no longer protected against malaria via this inherited gene mutation – but that’s a different story. What’s interesting is that red meat, which includes beef, pork, and lamb, contains significant amounts of the Neu5Gc protein and our bodies absorb it from the gut.
Once in our body, this protein appears to act as a foreign protein in our system, which triggers an immune response that leads to higher levels of systemic inflammation. We know that systemic inflammation is a major contributing factor to heart attacks, cancer, and type 2 diabetes. Consistent with this line of thinking is the fact that many human observational studies (epidemiological studies) show a strong correlation between consumption of red meat (beef, pork, and lamb) and increased risk of carcinomas (especially liver cancer or hepatocellular carcinoma), as well as atherosclerosis (narrowed, clogged arteries), type 2 diabetes, and all-cause mortality (increased risk of death from all causes). Evidence for a link between red meat intake and heart attacks in humans is particularly strong when you compare humans to other mammals who still produce the Neu5Gc protein.
What we know is that naturally occurring heart attacks due to atherosclerosis are virtually non-existent in other mammals, including closely related chimpanzees in captivity which share human-like risk factors, such as high blood cholesterol and triglycerides, high blood pressure and physical inactivity. Researchers are now suggesting that in addition to known risk factors for heart disease, such as high cholesterol, high blood pressure, smoking, inactivity, etc., that simply eating red meat (beef, pork, lamb) increases inflammation within our blood vessel walls, adversely affects blood vessel function (endothelial dysfunction), and is in itself a risk factor for heart attacks. The most recent study to suggest this was published on July 22, 2019 issue of the Proceedings of the National Academy of Sciences. In this study, scientists deleted the gene for Neu5Gc in a group of mice. This single gene mutation caused a 2-fold increase in atherosclerosis (narrowed arteries) in these mice, but in the mice fed a Neu5Gc-rich diet (red meat diet) the increase in atherosclerosis was another 2-4 fold higher, which could not be explained by changes in blood cholesterol, triglycerides or sugars. In previous work, the same researches showed that dietary Neu5Gc also promotes inflammation and cancer progression in Neu5Gc-deficient mice.
The bottom line in all this research is that consumption of red meat by humans is emerging as an independent risk factor for heart attacks, (and possibly other health problems), which is over above other known risk factors for heart disease. If a wellness lifestyle is truly one of your life’s quests, then I think you should pay heed to this research by omitting or greatly limiting red meat consumption, as one more strategy to protect your health, improve your healthy life expectancy and quality of life.
I have included the references for this information in the text below.
1. Kunio Kawanishi, Chirag Dhar, Raymond Do, Nissi Varki, Philip L. S. M. Gordts, Ajit Varki. Human species-specific loss of CMP-N-acetylneuraminic acid hydroxylase enhances atherosclerosis via intrinsic and extrinsic mechanisms. Proceedings of the National Academy of Sciences, 2019; 201902902 10.1073/pnas.1902902116
2. Samraj AN, Pearce PM, Laubli H, Crittenden AN, Bergfeld AK, Banda K, et al. A red meat-derived glycan promotes inflammation and cancer progression. Proc Natl Acad Sci USA. 2015 Jan 13: 112(2): 542-547. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4299224/
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