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Researchers at the University of Colorado Boulder (United States) have shown that a compound produced in the intestine when eating red meat damages the arteries.
The study, published in the American Heart Association's journal Hypertension, suggests that people can prevent or even reverse such age-related decline through dietary changes and targeted therapies, such as supplements. nutritional.
"Our work shows for the first time that this compound not only directly impairs artery function, but may also help explain the damage to the cardiovascular system that occurs naturally with age," the researchers explained.
When you eat a piece of steak or a plate of scrambled eggs, the resident gut bacteria immediately go to work breaking it down. As they metabolize the amino acids L-carnitine and choline, they produce a metabolic byproduct called trimethylamine, which the liver converts to trimethylamine-N-oxide (TMAO) and sends through the bloodstream.
Previous studies have shown that people with higher levels of TMAO in their blood are more than twice as likely to suffer a heart attack or stroke, as well as die, although the reasons were not known until now.
Against this backdrop, researchers measured the blood and arterial health of 101 older adults and 22 young adults, finding that TMAO levels increase significantly with age. This is consistent with a previous study in mice showing that the gut microbiome changes with age, generating more bacteria that help produce TMAO.
When the researchers fed TMAO directly to young mice, their blood vessels aged rapidly. And the 12-month-old mice (the equivalent of humans about 35 years old) looked more like the 27-month-old mice (80 years old in people) after eating TMAO for several months.
Preliminary data also show that mice with higher levels of TMAO exhibit declines in learning and memory, suggesting that the compound could also play a role in age-related cognitive decline.
On the other hand, old mice that ate a compound called dimethylbutanol (found in small amounts in olive oil, vinegar, and red wine) saw their vascular dysfunction reversed, so scientists believe this compound prevents the production of TMAO.
"The more red meat you eat, the more you feed the bacteria that produce it. The study is an important advance because it sheds light on the reasons why our arteries erode with age, even in the healthiest people," the researchers concluded. experts.
