Diet affects intestinal flora – hospital microbes multiply

Low-calorie diets are a popular way to lose weight. According to a recent study, they also have an effect on intestinal bacteria or the composition of the intestinal flora. So low calorie intake leads, among other things, to the accumulation of the bacterium Clostridoides difficile, known as the hospital germ, which in turn has an effect on weight regulation.

An international research team led by Professor Dr. Charité from Joachim Sprenger – Universitatsmedizin Berlin investigated the question of how a caloric diet affects the body and in particular the composition of the intestinal flora. It became clear that diets can profoundly alter the composition of microorganisms in the human gut. The results of the related study were published in the specialist journal “Nature“be released.

individual composition of the intestinal flora

The trillions of microorganisms in the gastrointestinal tract, also known as the microbiome or intestinal flora, vary from person to person, and in overweight and obese people, for example, the microbiome differs from that of normal-weight people. In a different press release, the results of the current study.

Effects of low-calorie diet studied

For the study, researchers examined the effects of an extremely low-calorie diet in 80 older women who were severely overweight. For this purpose, women either lost weight under medical supervision with a so-called formula diet (based on prepared drinks with less than 800 kcal per day) or they kept their weight stable over a 16-week period.

According to Charité, the test subjects were from the Center for Experimental and Clinical Research (ECRC), a joint facility of Charité and with the Max Delbrück Center for Molecular Medicine at the Helmholtz Association (MDC). Routine analysis of stool samples showed that “the diet reduced the number of microorganisms in the women’s intestines and changed the composition of the intestinal flora.”

profound changes in the intestinal flora

“We were able to show for the first time how a diet with a very low calorie content profoundly changes the composition of microorganisms in the gut and thus has a lasting effect on the energy balance of the human host,” said Professor Dr. Spanger.

It also became apparent that “bacteria alter their metabolism to take up more sugar compounds that are no longer available to humans,” said first author Dr. Rainer Jumpertz von Schwartzenberg from Charité. You could say that a hungry microbiome is developing.

Bacterial Weight Loss?

In further experiments, the scientists transferred stool samples taken from test subjects before and after the diet into germ-free mice without their own intestinal flora. Surprisingly, when the feces were removed after the diet was shifted, the animals showed weight loss — “more than 10 percent of their body mass within just two days,” reports the charity. In contrast, transplantation of stool samples prior to diet had no effect.

According to Professor Dr. Spanger, the results suggest that “this phenomenon can be explained primarily by changes in the absorption of food in the animal’s intestines.” It becomes clear here that intestinal bacteria have a decisive effect on food intake.

Hospital germs with increased presence

During a detailed analysis of the stool composition, the researchers found an increased colonization with the bacterium Clostridoides difficile. It is relatively widespread and can also be found in the intestines of healthy people and animals. However, if they multiply in the digestive tract, for example after antibiotic therapy, there is a risk of severe inflammation of the intestine. Because Clostridoides difficile is a significant problem in the clinical field, this bacterium is also known as the hospital germ.

C. Difficile responsible for weight loss?

In the present study, both test subjects that underwent a diet and mice that were transplanted with the corresponding human intestinal bacteria following a diet showed increased presence of Clostridoides difficile. “We were also able to prove that C. difficile produced specific toxins for the bacterium – even the animals’ weight loss was dependent on this,” explains Professor Spanger.

Despite the increasing presence of Clostridoides difficile, neither the test subjects nor the animals showed clinical signs of intestinal inflammation, the expert continues. An extremely low-calorie diet means that “a bacterium known as a hospital germ can multiply more easily and make the absorption of food through the intestinal wall less efficient – ​​but cause symptoms of illness.” Without.”

Can new medical options be explored?

The extent to which asymptomatic colonization with the bacterium may worsen or possibly even promote health is not yet clear and needs to be investigated in larger studies. The team would also like to investigate how gut bacteria might be affected to have beneficial effects on body weight and metabolism in humans. The knowledge gained may also result in potential therapy options for metabolic diseases such as obesity or diabetes.

The current “results underscore the importance of interactions between nutrition and the microbiome in modulating the host’s energy balance and illustrate the need to understand the role of nutrition in the interplay between pathogenic and beneficial symbionts,” sum up the researchers. . (FP)