Our gut is full of little creatures that help us digest food, protect us from harmful intruders, and act as a telephone line between our digestive system and brain. From bacteria and fungi to viruses, these microbial communities help keep our insides healthy.
But when we take medications, we upset this tightly managed ship. – And not just temporarily, a large new study finds. The impact of these medications can still be seen years later.
What’s more, it is not only antibiotics that cause these intestinal havoc, but also other common medications.
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“The effect of drug use has been underestimated,” a team led by genomicist Oliver Aasmets from the University of Tartu in Estonia writes in their article.
“The effects of antibiotics, psycholeptics, antidepressants, proton pump inhibitors and beta blockers are detectable several years after their use.”
Aasmets and his team investigated the records of 2,509 people who participated in the Estonian Biobank project.
Among the data, including a subset of 328 follow-ups, researchers were able to see how stopping and starting certain medications changed patients’ microbiomes. This suggests a possible causal effect, the researchers explain.
Of the 186 drugs the team investigated, 167 (nearly 90 percent) were associated with changes in fecal microbiome samples.
“In fact, human-targeted drugs appear to reduce diversity by eliminating specific taxa,” Aasmets and his team explain.
Benzodiazepines, commonly used for anxiety, had an equivalent impact to broad-spectrum antibiotics, well known to be destructive to our internal ecosystems.
Furthermore, not all benzodiazepines had equivalent effects. For example, alprazolam (brand name Xanax) had a broader impact on gut microbe diversity than diazepam (brand name Valium). This suggests that we may need to optimize which medications are not only best for a particular condition, but also cause the least damage to our microbiomes.
These impacts can also worsen.
“The more a drug is used, the greater the impact on the microbiome,” the researchers write.
“We identified carryover and additive effects.”
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Previous studies in mice suggested that long-term antibiotic use may alter the mucosal lining of the intestine, which may contribute to weight gain. The team calls for more research to determine the consequences of prolonged exposure to various classes of drugs.
“Most microbiome studies only consider current medications, but our results show that past medication use may be just as important as a surprisingly strong factor in explaining individual differences in the microbiome,” says Aasmets.
“We hope this encourages researchers and clinicians to take medication history into account when interpreting microbiome data.”
This research was published in mSystems.