Antibiotics are widely known to disrupt gut health by killing “good” as well as “bad” bacteria in the digestive tract.
Now scientists are also exploring if other common drugs can interfere with the trillions of microbes that constitute the gut microbiome — leading to changes that linger long after you stop taking the medication.
“This has been a hidden problem,” says Martin J. Blaser, MD, director of the Center for Advanced Biotechnology and Medicine at Rutgers University in Piscataway, New Jersey, as well as its chair of the human microbiome.
Two recent studies aim to better identify medications that impact the gut microbiome and explain their effects.
This kind of research is critical because a thriving microbiome is vital for human health. Not only do gut microbes help digest food, they also perform other vital functions such as training the immune system, and making vitamins, Dr. Blaser notes.
Antidepressants, Beta-Blockers, and Other Drugs May Impact the Gut Microbiome
In the first study, published in the journal mSystems, researchers analyzed stool samples and prescription medication information from more than 2,500 people who participated in the Estonian Biobank’s microbiome cohort.
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The researchers discovered that many medications were associated with noticeable changes in the gut microbiome, and the impact often lasted long after people stopped taking the drugs.
The study identified several kinds of medications with the potential to alter the gut microbiome, including:
Scientists Are Trying to Predict This Impact
For the second study, published in the journal Cell, researchers exposed human stool samples (often used to study the makeup of the microbiome) to more than 700 medications used to treat about 5,000 conditions, to identify what effect they might have.
The researchers discovered that 141 of the medications altered the microbiome, and even short-term treatments created lasting changes. Some of the medications completely wiped out certain beneficial microbes.
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While the gut microbiome is complex and unique to each person, the researchers created a computer model to predict the potential impact of medications generally on gut bacteria.
This framework could help guide doctors in the future investigating potential medication side effects and impacts on the gut microbiome, the researchers wrote.
Can Changes to Gut Health Harm Overall Health?
“The gut microbiome can have a huge role to play in our overall health,” says Sumona Bhattacharya, MD, a gastroenterologist and assistant professor of medicine at GW Medical Faculty Associates in Washington, DC.
It makes sense, then, that changes to the gut microbiome can have significant consequences. “Medications are all chemicals and have activities against cells, inhibiting their multiplication and sometimes killing them,” Blaser says. “But not all bacterial cells are equally susceptible to any agent. Some are more susceptible; some are more resistant.”
When someone takes an antibiotic, for example, populations of susceptible bacteria go down — allowing bacteria that are resistant to multiply. “This changes the composition and the balance” of the gut microbiome, Blaser says.
“With these big changes, having health concerns is appropriate,” Blaser says.
In addition to affecting digestion and bowel regularity, significant microbiome changes could also raise the risk of diseases like type 2 diabetes, obesity, and cancer, Blaser says.
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“One well-known connection is between microbiome characteristics and the risk of colon cancer, but other connections are being studied and new ones discovered all the time,” says Aditya Sreenivasan, MD, a gastroenterologist at Northwell’s Lenox Hill Hospital in New York City.
Signs Your Gut Microbiome Is Off-Balance
It can be hard to tell if any given symptom is the direct result of changes in your gut microbiome caused by a medication you’re taking, Dr. Sreenivasan says. “But in general, gastrointestinal issues ranging from diarrhea to bloating probably have something to do with it,” he says.
Blaser points out that there are currently no good tests to evaluate the balance of your gut microbiome — making it tough for doctors to pinpoint when your microbiome is off.
How to Lower the Risk of Disrupting Your Gut Microbiome With Medication
Bhattacharya stresses that it’s important to take medications as prescribed. But if you’re concerned about your gut health, Blaser recommends asking your doctor if you really need a particular medication, or if you can get by with a lower dose or shorter duration.
Doctors are wary of blanket recommendations for probiotic supplements as a way to replace microbes that may be wiped out by medications — and not only because the supplement industry is largely unregulated. “There’s not great evidence to show that probiotics truly diversify the gut microbiome,” Bhattacharya says.
Instead, she recommends eating a diverse, healthy diet that includes fruits, vegetables, and yogurt. “All of those can help enrich your gut microbiome,” she says.
Sreenivasan recommends adding fermented foods like kombucha and kimchi to the mix, too. “They may have some additional benefits as well,” he says.
If you’re struggling with gut health issues, it’s important to see a healthcare provider for an evaluation, Bhattacharya says. Unexplained weight loss, ongoing acid reflux, constant bloating, changes in bowel habits, or blood in your stool should be checked out quickly, Sreenivasan says.
