Years after swallowing the last pill, the bacteria that inhabit our gut retain the memory of past treatments, far beyond what scientists had imagined.
This discovery, from a large-scale Estonian study, reveals that nearly 90% of the medications analyzed durably alter the composition of the gut microbiome. Even more surprising: some effects, comparable to those of the most powerful antibiotics, persist years after stopping the treatment. This finding invites us to rethink our relationship with medications and digestive health.
Medications with unsuspected effects
Benzodiazepines, prescribed to soothe anxiety, behave like broad-spectrum antibiotics. Their footprint on the microbiome remains detectable more than three years after the end of treatment, disrupting the bacterial balance with unexpected intensity. These results, published in the journal
mSystems, emphasize that every ingested tablet leaves a mark, sometimes deeper than expected.
The study also highlighted striking differences between molecules from the same family. For example, alprazolam and diazepam, two commonly used anxiolytics, do not affect the microbiome in the same way. The former causes more extensive disturbances, revealing that each medication has a unique microbial signature, almost like a bacterial identity card.
The researchers analyzed data from more than 2,500 participants, combining stool samples and prescription histories over five years. This approach demonstrated that the accumulation of treatments over time amplifies changes in the microbiome. In other words, the more medications an individual takes from the same class, the more pronounced and lasting the changes observed in their gut.
A challenge for medical research
Studies on the microbiome usually focus on medications taken at the time of analysis. Yet, this Estonian research proves that medical history plays an equally important role. Ignoring past treatments risks misinterpreting the links between the microbiome and diseases, thus skewing the results of epidemiological studies.
To validate their observations, scientists examined follow-up samples taken after four years from 328 participants. Despite the small sample size, the results confirm that stopping or starting certain medications, such as proton pump inhibitors or antidepressants, leads to predictable changes in bacterial composition. Further proof that the microbiome is a faithful reflection of our therapeutic journey.
This study raises a fundamental question: what if the medications we take today shape the health of our gut for decades to come? The implications are vast, both for personalized medicine and for understanding chronic diseases. Researchers now call for systematically integrating medication history into microbiome analyses, a practice that could transform how we approach digestive health.
Article author: Cédric DEPOND