THE ESSENTIAL
- Researchers have identified lithocholic acid (LCA), an intestinal molecule produced by bacteria, as a potential player in slowing aging in animals subjected to a low-calorie diet.
- Although once considered toxic, LCA, in low doses, stimulates a protein called AMPK, linked to the reduction of muscle atrophy.
- Although the tests have not confirmed any impact on the longevity of mice, this molecule illustrates the key role of the intestinal microbiota. Researchers plan to study its potential effects in humans.
Potential new proof of the importance of the intestinal microbiota in our health: researchers from China and the United States have identified a molecule that could play a role in slowing aging in certain animals subjected to a restrictive diet. Tracing the history of research into the effects of low-calorie diets, the results of their work were published in two articles in the journal Nature.
Restrictive Diet, Lithocholic Acid, and Overall Health
For years, studies have shown that a low-calorie diet can improve health. In some animals, such as fruit flies and nematodes (microscopic worms), this type of diet even extends life expectancy. But testing these effects on humans remains complex due to their relatively long life expectancy. To get around this obstacle, scientists are turning to other avenues, notably the study of molecules produced in the intestine.
In this new study, the team focused their efforts on lithocholic acid (LCA), a bile acid produced by intestinal bacteria, explains a press release. Although once considered toxic, recent research has found that in low doses, LCA may provide health benefits. In mice, consumption of LCA in small doses led to an increase in the production of a protein called AMPK, known to slow down muscle atrophy.
To arrive at these conclusions, the researchers monitored the levels of different metabolites in the intestines of mice placed on a restrictive diet. Among hundreds of compounds identified, LCA has emerged as a main player in AMPK activation. However, no evidence was found for an effect of LCA on the longevity of mice.
Complex mechanisms still to be deciphered
In a second study, researchers explored how LCA activated AMPK. They discovered that this process depends on certain members of the sirtuin enzyme family, which play crucial roles in several essential biological processes, such as cellular metabolism, stress response and longevity. Although the precise mechanisms at work remain to be elucidated, this research opens new perspectives on the interactions between intestinal metabolites and aging.
Although LCA did not show a direct effect on the lifespan of mice, its potential health benefits warrant further investigation. Researchers hope to establish whether these effects can be transposed to humans or discover other promising metabolites. In the meantime, this study reaffirms the importance of the intestinal microbiota in understanding our health and aging.