It's possible that among the millions of bacteria living in your gut, at least one microbe might change how your body processes food and affect your weight, a small French study suggests.
The microbe - Akkermansia muciniphila - makes up 3 percent to 5 percent of the gut bacteria. The strain is linked with a fiber-rich diet. It's also associated with lower levels of blood sugar, insulin and fats, which help ward off obesity, diabetes and heart disease. A. muciniphila also helps with a healthier distribution of body fat, the researchers said.
"This bacteria is a potential target for new therapies in the field of metabolic disease," said lead researcher Dr. Karine Clement, director of the Institute of Cardiometabolism and Nutrition at Pitie-Salpetriere Hospital in Paris.
"However, first the molecules produced by this bacteria have to be identified to explain this improvement," she said.
This bacteria produces a variety of substances that may serve as energy sources for other bacteria in the body, Clement said.
It's possible that A. muciniphila may contribute to the expansion of other beneficial bacteria as well as having a beneficial effect of its own, she said.
The report was published online June 22 in the journal Gut.
How the study was done
For the study, Clement's team looked at the amount of this microbe and other bacteria living in the guts of 49 obese or overweight people. The majority of participants (41) were women. The researchers also looked at blood sugar, blood fats and other factors that influence belly fat.
Researchers measured these factors before and after participants started a six-week, low-calorie diet that included extra protein and fiber. Restricting calories alters gut bacteria, the researchers said.
At the start of the diet, people with a lot of A. muciniphila in their gut had lower blood sugar, and lower insulin levels, smaller waists and fewer fat cells under their skin than those with low levels of the bacteria, the researchers found.
In addition, people with a lot of A. muciniphila along with other types of bacteria in their gut had the lowest blood sugar and blood fat and the best distribution of body fat, the researchers said.
After six weeks of calorie restriction, those who started with the most A. muciniphila had the biggest improvement in their blood sugar, insulin levels and body fat distribution, compared with those with the lower levels of the bacteria, the study found.
The researchers noted that they measured bacteria levels from stool samples, so it isn't clear if these levels are the same in the gut as they are in the feces. They also said it's not clear if changes in bacteria levels would last after calorie restriction.
Samantha Heller, a senior clinical nutritionist at NYU Langone Medical Center in New York City, said that the bacteria in your gut are essential for life.
"Our gastrointestinal tract houses an assortment of 1,000 or so species of bacteria," she said.
There are about 1 trillion microbes "renting space in our gut," Heller said. "We offer them housing and they in turn help retrieve nutrients from food, improve digestion, keep the gut wall healthy, fight off germs and create compounds that fight disease," she explained.
In fact, research is finding that these microbes play such important roles in human health and disease that the very survival of the human species may be dependent upon them, Heller said.
"Researchers are in the midst of teasing out which microbes have what effects in the body, but they believe that a balance of the various kinds of good microbes is important," she said.
A more plant-based diet, regular exercise and sleep have been found to help support a thriving and diverse gut community, Heller said.
In terms of weight management, the research in this area is very new, she said.
"However, obesity was not the problem 50 or 100 years ago that it is now," Heller said. "What we do know is that consuming excess calories, eating highly processed foods, junk and fast foods, and being sedentary are huge contributors to obesity. One single microbe can't undo an unhealthy lifestyle," she said.
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Sources U.S. Centers for Disease Control and Prevention.