Increased serotonin release As an intestinal bacterium promotes overweight

Clostridium ramosum: bacterium promotes overweight

It has been known for some time that certain intestinal bacteria can have an impact on weight. One of them is Clostridium ramosum. Researchers have now discovered how this bacterium promotes overweight.

Intestinal bacteria affect the weight

In recent years, various scientific studies have shown that some intestinal bacteria can influence the weight. Studies have shown that these bacteria control our satiety, trigger the yo-yo effect and can cause overweight. But how such effects come about, is hardly understood so far. German researchers have now gained new insights.

Certain intestinal bacteria can influence the weight. German researchers have now been able to show how the intestinal bacterium Clostridium ramosum promotes obesity. (Image: fotoliaxrender / fotolia.com)

The messenger substance serotonin is increasingly released

Researchers from the German Institute of Human Nutrition (DIfE) reported years ago that the bacterium Clostridium ramosum promotes obesity.

Their findings were published in "mBio®", the "Open Access Journal" of the American Society for Microbiology.

Now a DIfE research team was able to show how this effect comes about.

In the scientific journal "Scientific Reports" they report that Clostridium ramosum causes the intestinal cells of mice to increasingly release the neurotransmitter serotonin.

Serotonin promotes fat absorption from the intestine, which helps make fat deposits faster.

One hundred times smaller than a grain of sand

According to the information Clostridium ramosum is a ten-micron-sized bacterium and thus about 100 times smaller than a grain of sand. The spore-forming microbial species is increasingly found in the intestine of overweight people.

It is unclear, however, whether those affected by the bacterium gain weight. In animal experiments, the data situation is clearer.

"In previous studies with mice, we observed that Clostridium ramosum promotes obesity by increasing the number of fatty acid transporters in the gut," said Professor Michael Blaut, head of the Gastrointestinal Microbiology Unit at DIfE.

The scientists continued to pursue this trail. For this they examined mice and intestinal organoids.

These are derived from stem cells and have similar properties to normal intestinal tissue. That is why they are also called "mini-intestines".

The research team observed that Clostridium ramosum causes the intestine of the animals to increasingly form enterochromaffin cells. These specialized cells produce the messenger serotonin.

The bacterium can thus increase the concentration of serotonin in the intestine and increase the number of fatty acid transporters. One possible consequence for mouse and human: obesity.

"The study shows once again how strong the influence of a single bacterial species in the gut can be," emphasized Blaut.

Optimal multiplication under a high-fat diet

According to the experts, especially a diet high in fat could be problematic. Because the bacterium multiplies optimally under a high-fat diet.

"Our results provide an important indication of the interaction between diet, metabolism of the host and intestinal bacteria," Dr. Ana Mandic, researcher at the department who has been working on the project for almost three years.

In the next step, it is important to examine the extent to which Clostridium ramosum contributes to overweight in humans.

The researchers also want to find out if the bacteria could be stopped by a certain diet and other microorganisms. (Ad)