Alert: The Worst Antibiotics for Your Gut Health


From Bottom Line Health

How bad are antibiotics for your digestion and gut health, really?

Here’s the answer: Worse than you may have ever imagined.

The latest study finds that the damage from certain common kinds of antibiotics may unsettle the beneficial bacteria in your gut for months, even a year—in ways that could lead to diseases such as inflammatory bowel disease, even increase risk for colon cancer.

But some other antibiotics disturb your gut for only a week or so. Here’s information on which antibiotics are the most dangerous for your gastrointestinal health—and how to protect yourself from them.


We humans are more colonies than individuals. We rely on multitudes of beneficial bacteria in our gut and our mouths to thrive. To find out what happens to our gut microsystem during a single course of antibiotics, Swedish and British researchers gave healthy adults either a placebo or an oral antibiotic. They collected samples of saliva and feces before and after a course of antibiotics.

Four common types were studied…

• Amoxicillin. Class: Penicillin-like. It’s prescribed to treat bronchitis, gonorrhea and infections of the ears, nose, throat, urinary tract and skin.

• Minocycline. Class: Tetracycline. It’s prescribed to treat respiratory infections, acne and other skin conditions, as well as urinary and genital infections.

• Ciprofloxacin. Class: Fluoroquinolone. It’s prescribed to treat urinary tract infections, as well as anthrax. It’s commonly called “Cipro.”

• Clindamycin. Class: Lincomycin. It’s prescribed for infections of the lungs and skin and for vaginal infections.

Not surprisingly, all of the antibiotics knocked out many of the beneficial bacteria both in the study participants’ saliva and in feces. The good news is that in the mouth, the “good” bugs repopulated pretty quickly after all four kinds of antibiotics.

But the gut didn’t do so well. For the amoxicillin, the concentration of good gut bugs was disturbed for about a week. For monocyline, it was about a month. But for the heavy hitters ciprofloxacin and clindamycin, the damage was more lasting. They wiped out many of the beneficial bugs.

In particular, they destroyed several kinds of common gut bacteria that produce a short-chain fatty acid called butyrate—which is increasingly being recognized as one key to a healthy colon. Butyrate inhibits inflammation, acts as a powerful protective antioxidant and helps stop cancer from forming. When good-for-you bugs are killed and stop producing butyrate, other studies have shown, that can contribute to digestive disorders such as inflammatory bowel disease.

In this study, ciprofloxacin and clindamycin wiped out the butyrate producers for several months—and in some cases, as long as a year.

Does this study mean you should never accept a prescription for these antibiotics? That’s going too far, since some infections that can be treated by these and other antibiotics can be life-threatening. But if you are prescribed antibiotics in the fluoroquinolone or lincomycin classes, discuss with your doctor if there are alternative classes of antibiotics that may work for your specific infection.

And there are many situations where antibiotics are prescribed when they’re not needed at all. That contributes to the worldwide epidemic of antibioticresistance, may increase the risk for diabetes—and, according to this study, may in some cases damage the digestive system in ways that can contribute to long-term health problems.

So take ’em if you really need ’em. But never take them lightly—and consider your alternatives.

SOURCE: Study titled “Same Exposure but Two Radically Different Responses to Antibiotics: Resilience of the Salivary Microbiome versus Long-Term Microbial Shifts in Feces” by researchers at University of Amsterdam, VU University Amsterdam, Swammerdam Institute for Life Sciences, The Netherlands, TNO Earth, Life and Social Sciences, The Netherlands, Karolinska University Hospital, Sweden, Helperby Therapeutics Limited, United Kingdom, UCL Institute of Child Health, United Kingdom and UCL Eastman Dental Institute, United Kingdom, published in the American Society for Microbiology’s journal MBio.