If you think you’re doing yourself a favor by ordering an omelet at brunch, think again. Eating an excessive amount of eggs may increase the risk of heart disease and stroke—even for people without traditional risk factors—according to a new study from the New England Journal of Medicine. Even more surprising: the reason why eggs may be dangerous. It was previously thought that the cholesterol in eggs promoted heart disease, but this research shows that there may be other factors at play.
Turns out, a metabolite found in egg yolks called lecithin may be to blame. When lecithin is digested, it breaks down into its different components, including the chemical choline. When intestinal bacteria metabolizes choline, it releases a substance that the liver then converts into a compound called trimethylamine N-oxide (aka TMAO), explains lead study researcher Stanley Hazen, MD, PhD, chairman of the department of cellular and molecular medicine at the Cleveland Clinic Lerner Research Institute. TMAO accelerates the rate at which plaque and cholesterol collect in the arteries, increasing the risk of heart disease and stroke.
These findings come just two weeks after the same group of researchers reported a link between carnitine (found in beef and some energy drinks) and heart attack risk. “Both studies show a potential new way for identifying patients at risk for heart disease,” says Hazen.
So should you ditch eggs altogether? Not necessarily. More studies are needed to confirm the results. In the meantime, moderation is key, says Hazen. He suggests cutting back on fatty, cholesterol-laden foods that contain chemicals that convert to TMAO. “Forego whole eggs,” he suggests. “Since the yolk is the only source of choline in an egg, egg whites are the safest bet—and are also an excellent source of low-fat protein.”
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