While the harm that the production of eggs for human consumption is undeniable in terms of environmental damage and animal cruelty, the health aspects of eating eggs can be confusing. My patients tell me that many health care providers have advised them to add eggs back to their plant diet to avoid illness. If the high content of saturated fat and cholesterol weren’t enough, a new pathway in which eggs harm arteries, kidneys, the heart and other organs has led responsible health researchers to advise avoiding eggs for anyone with “vascular” disease. What is the new data?
The new answer to the age old question “where do you get your protein?” is “where do you get your TMAO?” TMAO, or tri-methyl amine oxide, is a newly described compound that our bodies produce and that has created a whole new field of understanding the diet-health hypothesis. TMAO is a chemical produced by intestinal bacteria as a result of our dietary choices and the composition of our gut bacteria. Work at the Cleveland Clinic has shown that TMAO increases the accumulation of cholesterol in the wall of arteries to begin plaque buildup. The researchers also demonstrated that it was the bacteria in the GI tract that were producing TMAO. Until now, the focus on dietary sources of TMAO production has been mainly on foods rich in choline and l-carnitine such as fish and red meat. In fact, large research studies have recently identified an association between dietary phosphatidylcholine intake (e.g. liver and pork) with both Type 2 diabetes and all-cause and cardiovascular mortality. The bottom line is, eating animal products can lead to high blood levels of TMAO and put health at serious risk.
Circling back to eggs, the phosphatidylcholine in the yolk of eggs can drive TMAO up to high levels. A recent article from a prestigious medical center provides further reason to just say no to eggs, no matter what your doctor or trainer says. With a title of “Dietary Cholesterol and Egg Yolk Should Be Avoided by Patients at Risk of Vascular Disease”, Dr. David Spence clarifies that the discussion preceding recent USDA food guidelines to drop dietary cholesterol as a nutrient of concern was heavily polluted by input from the egg industry that had everything to lose. In patients at risk for vascular disease (all of us but particularly those with high blood cholesterol, blood glucose, blood pressure, family history of heart attacks, and smokers) the goal of limiting daily dietary cholesterol to <200 mg a day remains valid. That is less than the cholesterol in a single large egg (which actually has as much cholesterol as a 12-ounce burger). Dr. Spence pointed out the rise in levels of TMAO after just 2 egg yolks was associated in other studies with a 250% increase in risk of stroke, heart attack and death over 3 years! For all of those reasons, avoidance of eggs was advised.
While we are at it, eating fish deserves some condemnation too in terms of recent TMAO data. In a study involving 40 healthy men eating various meals, eating fish meals yielded the highest circulating TMAO levels with a rise that was 46–62 times baseline. The rise in TMAO was higher following fish than beef, eggs or the fruit control. The rise in TMAO began only 15 minutes after eating a meal of fish.
Overall, the last 6 years of science and over 1,000 peer-reviewed publications points out the fact that TMAO is a bad ass chemical to be avoided in your blood stream. Whether you are motivated by saving the planet, kindness to animals, hour health or all of the above, bypassing eggs and foods with eggs in them may help you also avoid a bypass to your heart at the same time. To health!