How gut bacteria influence the effect of drugs - Heilpraxis

Interactions between intestinal bacteria, food and drugs

Medicines do not work the same way for everyone. According to a renowned biochemist, the effectiveness of a drug also depends on a person's intestinal flora. Recent research suggests that the gut microbiome plays a critical role in drug efficacy.

Dr. Michael Zimmermann is a biochemist at the European Molecular Biology Laboratory (EMBL) in Heidelberg. In an interview with the Daimler and Benz Foundation, the expert explains how intestinal bacteria influence the effectiveness of drugs.

Gut bacteria affect drug effectiveness

The microbiota in the gut is often referred to as gut flora. This means all microorganisms that have settled in a person's intestines. Studies in recent years have repeatedly shown that gut bacteria produce important metabolic products that are important for human health in general.

as doctor Zimmermann reports that intestinal bacteria are also capable of activating or deactivating certain active principles of drugs. Conversely, certain drugs such as antibiotics in turn modify the composition of the intestinal flora, which can have undesirable effects.

The team around Dr. Zimmermann examines this interaction. Scientists want to ensure that patients receive drugs that are tailored to the respective intestinal flora. The research work is funded by the Daimler and Benz Foundation to the tune of 40,000 euros.

Since when is the influence of the intestinal flora on drugs known?

“In fact, the gut microbiome has only been at the center of science for two decades,” explains the biochemist. This is mainly due to technological developments. Today, it is possible to sequence the DNA of intestinal bacteria in a short time.

“However, the idea that gut flora influences the effect of drugs has been around for a long time; 50 years ago, there was even a first scientific conference on this subject,” explains Dr. Charpentier. But it is only today that it is possible to deepen these relations.

Size of the intestinal flora

"Our body is heavily populated, with at least as many microbes as we have in our own body cells," says the expert. Microorganisms pack 150 times more bacterial genes than we have human genes in our body.

Huge scientific potential

From a scientific point of view, this is fascinating because the microbiome has enormous metabolic potential. "We don't yet understand a lot of his genes," says Dr. Charpentier.

The scientist sees an immense treasure of knowledge hidden in the intestinal flora. "After all, the microbiome is relevant to food intake, metabolism and the immune system," says the researcher.

How does the intestinal flora differ from person to person?

"Although we humans are only genetically different by less than one percent from each other, the difference in microbiome from one person to another can reach 80%", specifies the biochemist. The interaction is sometimes influenced by diet, lifestyle and disease.

Cultural differences are also evident. "Our European diet, for example, is no longer as high in fiber as in other cultures or in earlier times," says the microbiome expert. This could lead to partial loss of the microbiome.

The working group around Dr. Zimmermann uses different approaches to study the intestinal flora. Among other things, the team wants to find out what microbes are biochemically capable of and how they interact with drugs.

The intestinal flora is not designed to metabolize drugs

"We can learn a lot from basic research, because the evolution of bacteria was not originally designed to metabolize drugs in our bodies — that's only been happening for about a century," says Zimmermann.

As part of the research, the team works with hospitals. Researchers analyze the microbiome of sick people and sequence the DNA of gut bacteria. Associations with certain diseases or interactions between drugs and bacteria can be discovered.

Medicines adapted to the intestinal flora

"We hope that our findings and results will make a significant contribution to personalized medicine in the years to come: after submitting a stool sample and analyzing their microbiome, patients should in the future receive the right medicine at the right dosage", explains the biochemist.

In the best case, the positive effect of a drug should be exploited to the maximum while the intestinal microbiome is little influenced. It is different for drugs that can be used specifically to improve the composition of the intestinal flora, such as prebiotics or probiotics.

improve the treatment of many diseases

According to Dr. Zimmermann's discoveries could improve the treatment of many diseases. According to him, “the chronically ill would benefit in particular; for example people with high blood pressure, diabetes, autoimmune diseases or psychotic disorders – and of course people who have had an organ transplant, for whom adjusting the immune system is always a therapeutic tightrope walker” .

Let food be your medicine

The Greek physician Hippocrates is said to have said, "Let food be your medicine and medicine your food." As Zimmermann points out, this is still valid: “We don't just want to describe this with our research, we want to predict it. !"

"A better understanding of the functions and metabolism of the intestinal microbiome seems to be an important key", summarizes the expert in intestinal bacteria. (vb)

Author and source information

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This text corresponds to the specifications of the specialized medical literature, medical guidelines and current studies and has been verified by health professionals.


Graduate editor (FH) Volker Blasek


Daimler and Benz Foundation: Do intestinal bacteria determine the effectiveness of a drug? (PDF, published July 6, 2022),

Important note:
This article contains general advice only and should not be used for self-diagnosis or treatment. It cannot substitute a visit to the doctor.