By Lisa Marshall

Principal investigators
Vienna Brunt; Doug Seals

Funding
National Institutes of Health (NIH)

Arteries in human body graphicA compound produced in the gut when we eat red meat playsÌýa key role in boosting heart disease risk with age, suggestsÌýresearch published by integrative physiology ProfessorÌýDoug Seals.

Eat a steak and your gut bacteria break it down, churningÌýout a metabolic byproduct called trimethylamine, whichÌýthe liver converts to trimethylamine N-oxide (TMAO).ÌýPeople with higher blood levels of TMAO are knownÌýto be twice as likely to have a heart attack andÌýtend to die earlier.

But scientists haven’t known why.Ìý

When the researchers studied 101Ìýolder adults and 22 young adults, theyÌýfound that TMAO levels rise with age,Ìýand adults with higher blood levelsÌýhad worse artery function and moreÌývessel damage. When fed TMAOÌýdirectly, young mice swiftly beganÌýto look like old mice in terms ofÌývessel health.

Even a young veganÌýproduces some TMAO.ÌýBut over time, the studyÌýsuggests, eating excessÌýanimal products mayÌýprompt you to makeÌýtoo much, exacerbatingÌývascular decline.