Intestinal bacteria + L-carnitine = atherosclerosis
Red meat harms the heart
However, even if you choose meat with a minimum amount of fat for a steak or cutlet, this does not mean that you will be able to avoid heart problems. As studies by scientists from the Cleveland Clinic (USA) have shown, red meat itself can upset cardiovascular health.
However, scientists have already drawn attention to the fact that intensive consumption of red meat, even with a low level of fat in it, increases the likelihood of death from heart problems. However, for the time being, this remained only a simple statistic, although very intriguing. Researchers from the Cleveland Clinic, led by Stanley Hazen, tried just to get to the bottom of the reasons for this statistic. And the reasons, as one might expect, turned out to be related to the intestinal microflora.
For the experiment, scientists invited 77 volunteers and began feeding them L-carnitine (levocarnitine), an amino acid that is found in particularly large quantities in red meat, although there are also in other foods. Some of those who participated in the experiment were vegetarians of varying degrees of conviction, and in their case it was possible to track only the effect of L-carnitine, without paying attention to other "meat" substances.
As researchers write in Nature Medicine (Koeth et al., Intestinal microbiota metabolism of l-carnitine, a nutrient in red meat, promotes atherosclerosis), intensive use of L-carnitine increased the level of trimethylamino-N-oxide (TMAO) in the blood. TMAO is also believed to affect the intensity of cholesterol metabolism, and the more TMAO, the slower cholesterol leaves the walls of blood vessels. And what is fraught with cholesterol on the walls of blood vessels, we all know well.
However, in the tested vegetarians, the level of TMAO in the blood was still lower than in meat-eaters. Scientists explain this by the fact that different bacteria live in the digestive tract of both: this was confirmed by appropriate analyses. That is, L-carnitine did not by itself lead to an increased level of TMAO, this required intermediaries in the form of bacteria. And the bacteria most likely appeared due to the meat diet.
Scientists conducted a statistical study among 2,600 people, and the link between L-carnitine, TMAO and cardiovascular diseases was confirmed: the more L-carnitine and TMAO were, the more noticeable were heart problems. Experiments on mice confirmed the role of microflora: if rodents were deprived of gastrointestinal bacteria, L-carnitine had no effect on the formation of atherosclerotic plaques in the vessels. That is, with a high degree of confidence, we can say that it is bacteria with the help of meat L-carnitine that increase the level of TMAO and increase the likelihood of cholesterol accumulation on the walls of blood vessels. What kind of metabolic transformations are taking place here, scientists have yet to find out.
These data force us to take a different look at the ideas about the "usefulness" or "harmfulness" of certain foods. Perhaps there are no products at all that would be useful or harmful in themselves, and their effect on the body must be determined, taking into account the "opinion" of the microflora. Who knows, maybe even the most useful organic-natural-vegetable products consumed by the most faithful vegetarians can cause very powerful harm to health – if they only fall into the "paws" of the wrong bacteria.
Prepared based on Nature News: Red meat + wrong bacteria = bad news for hearts.
Portal "Eternal youth" http://vechnayamolodost.ru08.04.2013