Study Says Eggs May Increase Heart Disease Risk

CLEVELANDNew research published in The New England Journal of Medicine suggest lecithin, found abundantly in egg yolks, interacts with intestinal bacteria and raises plasma levels of trimethylamine-N-oxide (TMAO), which raises the risk for heart attack and stroke. The findings supports earlier evidence that circulating TMAO is proatherogenic and may be a biomarker of later cardiovascular risk.

Recent studies in animals have shown a mechanistic link between intestinal microbial metabolism of the choline moiety in dietary phosphatidylcholine (lecithin) and coronary artery disease through the production of  TMAO. Lecithin is broken down in the body and produces choline that gets metabolized by intestinal bacteria, which triggers the liver to produce TMAO.

Researchers at the Cleveland Clinic Lerner Research Institute investigated the relationship among intestinal microbiota-dependent metabolism of dietary phosphatidylcholine, TMAO levels, and adverse cardiovascular events in humans.

To show the effect of eggs on TMAO, study participants were asked to consume two hard-boiled eggs before and after the suppression of intestinal microbiota with oral broad-spectrum antibiotics. Plasma levels of TMAO were markedly suppressed after the administration of antibiotics and then reappeared after withdrawal of antibiotics.

They further examined the relationship between fasting plasma levels of TMAO and incident major adverse cardiovascular events (death, myocardial infarction, or stroke) during a 3-year follow-up in 4,007 patients undergoing elective coronary angiography at the Cleveland Clinic. Results showed those with higher levels of TMAO in their blood were at higher risk for heart attack or stroke.