Fiction or reality: What do we really know about the influence of the microbiome?

Hypotheses, unnecessary laboratory tests and suspicious interventions – the microbiome, a topic on which there are many different opinions and opinions. At the annual press conference of the German Society of Gastroenterology, Gastroenterology and Metabolism, an impressive warning was delivered Tuesday about previously unproven theories and purported health-promoting interventions.

“The microbiome is a collection of microorganisms and their genes (microorganisms) that live in a particular environment, such as the gastrointestinal tract. There is a lot of evidence and speculation that the gastrointestinal microbiome (‘bacterial flora’; n.d.) plays an important role in the body. Evolution (eg the immune system; NB), regulating many body functions (eg GI functions; NB) and in diseases (eg, chronic inflammatory bowel disease, irritable bowel syndrome, gut-brain axis disorders; NB)” stated Thomas Freeling, chief medical officer at the clinic. Medical Gastroenterology Clinic Krefeld.

Missing definition of ‘healthy microbiome’

The Problem: Scientifically, it is still difficult to understand the structure, effect, and possible health-promoting interventions through the bacterial makeup of the intestinal flora, even if there has been a real buzz about it in the health business in recent years. “Despite great efforts and extensive scientific investigations, we are still unable to identify the ‘healthy’ microbiome in the human gut,” the expert added.

Completely erroneous opinions about the extent and composition of the microbiome have long been in circulation. Minimizing: “Basic ideas about the amount of microbiome that is repeatedly presented in many works are wrong according to recent scientific studies. The mass of the microbiome does not range from 1.5 to 2 kg, and the amount of bacteria in the human body does. The number of cells in the human body does not exceed ten Fold. We now know that the bacterial mass in the human body is “only” about 200 grams, which is about 100 grams in the intestine, and the ratio of the number of bacteria to the number of body cells is almost the same.

Diet is a major factor, but…

The reasons for the diversity of gut bacterial species, which are often described as important, are also unclear. Gastroenterologist: “Therefore, we still do not know precisely how we have to modify the human microbiome in such a way that health can be positively affected. Although nutrition is a major factor in affecting the microbiome and energy balance in the body, our knowledge is still incomplete. complete on this matter.

In the meantime, laboratory tests of stool samples are often touted as a way to quantify and “quality” the gut microbiome. Apart from tests in the case of severe gastrointestinal disease, this appears to be unreliable. Fragmentation: “While the search for pathogens (causative; NB) in stool – eg salmonella or rotavirus – has been established to elucidate diarrheal diseases, screening of the individual microbiome is of no clinical significance and is not recommended in accordance with our current IBS Guidelines. “. The reason is that the results of these studies are not really reliable regarding the microbiome due to the lack of standardization.

Medical knowledge about the microbiome is incomplete

Therefore, knowledge in medicine about the importance of the gut microbiome for health and disease is incomplete. Deriving interventions or even treatment strategies from this means working on the basis of unclear data. So far, the information has mainly come from animal experiments. Expert: “While there are impressive findings about the effect or initiation of diseases by fecal microbiome transfer in neurological, rheumatic or metabolic diseases and also in irritable bowel syndrome in animal experiments, the clinical relevance in humans is unclear.” Although the decrease in intestinal microbial flora diversity can be identified in various diseases, it is not known whether this is ‘disease specific’ or what bacteria are likely to be involved. “The effect of specific nutrition or diets on microbiome-mediated changes in metabolism or weight behavior is also unclear in their clinical relevance in humans.”

After all, this applies to them too Probiotics application Also, which has been heavily advertised for years. “The data is scarce,” the gastroenterologist said. Positive study data are available for so-called microbiome transfer (“fecal transfer”; note) for the treatment of recurrent acute gastroenteritis due to Clostridium difficile infection alone. In the case of irritable bowel syndrome, such a procedure outside of scientific studies is currently not appropriate.

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