Study: Common Medications Could Alter Your Gut

A new study shows that commonly used drugs can alter the microbes in the gut and raise the risk of antibiotic resistance.

Dutch researchers say at least 1,000 species of bacteria found in the gut are influenced by several factors, including medication. These changes are associated with obesity, diabetes, liver diseases, cancer, and neurodegenerative diseases.

"We already know that the efficiency and the toxicity of certain drugs are influenced by the bacterial composition of the gastrointestinal tract and that the gut microbiota has been related to multiple health conditions; therefore, it is crucial to understand which are the consequences of medication use in the gut microbiome," said lead researcher Arnau Vich Vila, from the University Medical Center Groningen.

Researchers analyzed 41 commonly used drug categories in the stool samples of 1,883 people who did and did not take the drugs.

The categories with the biggest impact on the microbiome were:

  • Proton pump inhibitors (PPIs), used to treat indigestion, peptic ulcer, H. pylori eradication, gastro reflux and Barrett's esophagus.
  • Metformin, used to treat type 2 diabetes.
  • Antibiotics, used to treat bacterial infections.
  • Laxatives, used to treat and prevent constipation.

The collection of gut bacteria from PPI users had higher levels of upper gastrointestinal tract bacteria and increased fatty acid production. Meanwhile, users of metformin showed higher levels of potentially harmful E. coli bacteria.

Researchers also found that seven other drug categories were associated with significant changes in the bacterial populations; those who used SSRI antidepressants showed higher levels of Eubacterium ramulus (a potentially dangerous bacteria), while the use of oral steroids was associated with high levels of methanogenic bacteria. This strain is linked with obesity and an increase in body mass index.

"Our work highlights the importance of considering the role of the gut microbiota when designing treatments and also points to new hypotheses that could explain certain side-effects associated with medication use," Vila said in a meeting news release.

The study was presented at the United European Gastroenterology annual meeting in Barcelona. Such research is considered preliminary until published in a peer-reviewed journal.