Photo: Taryn (Flickr)
The fact that eating lean cuts of red meat elevates one’s risk for heart disease has been something of a puzzle for health experts. If the fat and cholesterol aren’t there to harden and clog arteries, then what could be the culprit?
Now, in a paper published this week in Nature Medicine, scientists are suggesting that the microflora inhabiting our intestines may be the missing link.
According to the new hypothesis, when certain kinds of gut bacteria break down carnitine – a compound found in red meat and dairy products — a new compound called trimethylamine-N-oxide (TMAO) is synthesized and released into the bloodstream. It is known that higher TMAO concentrations can lead to increased plaque build-up inside blood vessels.
To test their idea, researchers from the Cleveland Clinic gave red meat to 77 volunteers — including 26 vegetarians and vegans — and monitored the amount of TMAO coursing through their bodies over the next few hours. Whereas routine meat eaters saw their TMAO levels rise markedly, the effect in the non-carnivors was far less pronounced, suggesting that omnivores have different kinds of bacteria in their guts than non-meat eaters do.
These results were further corroborated by fecal tests performed on samples taken from the 77, blood analysis conducted on a different group of 2,600 people, and experiments carried out on mice.