Antibiotics May Directly Damage Gut Barrier, Increase IBD Risk

New evidence shows how antibiotics, often relied upon for treating complications of inflammatory bowel disease (IBD), may play a role in causing the conditions.

A study, published Sept. 11 in Science Advances, found that antibiotics hindered mucus secretion in mice, creating holes in the protective mucosal layer of the gastrointestinal (GI) tract that allowed bacteria to penetrate the intestinal barrier wall. This contributes to ulcers—hallmarks of Crohn’s disease and ulcerative colitis—the two forms of IBD.

The findings offer a new explanation for why antibiotic use is harmful to gut health. Existing evidence has shown that antibiotics compromise immune health by destroying beneficial microbes as well as harmful ones.

When Shai Bel, Azrieli faculty of medicine at Bar-Ilan University in Israel and the study’s lead author, set out to do the study, he didn’t expect to observe antibiotics directly harming body cells, he told The Epoch Times. “We are always taught that antibiotics harm bacteria and not us,” he said. “That’s why they are safe to use. Unlike many other medications, very little thought is given to adverse effects when prescribing antibiotics,” he added. “Perhaps it is time to reassess our assumptions.”

Immediate Effect

In the study, mice were treated with four different classes of antibiotics, by infusion and orally.

Each type of drug impaired the mucosal barrier, with mucus secretion reducing dramatically immediately following the vancomycin infusion.

In order to prove that it wasn’t the microbiota driving the mucosal changes (microbiota play a role in mucus production), the researchers transferred the microbiome of mice treated with vancomycin to mice without a microbiome. While the recipient mice adopted features of the donor microbiome, their mucosal barriers remained intact.

The research team hypothesized that antibiotics would cause intestinal inflammation by disrupting the colonic mucus barrier. They initially expected this disruption would occur through changes to the microbiota. However, Bel said he and his fellow researchers were surprised to find another root cause for intestinal inflammation.

Bel’s concern about antibiotic overuse is what motivates him to study the drug’s role in IBD. His research team plans to follow up this study with one that tries to determine, by looking at other risk factors, why only some people who take antibiotics are developing IBD.

“This is really frightening when you think about the fact that you can’t really avoid antibiotics,” Bel said. “They’re in our food, water, and sometimes you simply need to take it because you are ill.”

Who’s at Risk

IBD affects 2.39 million Americans of all ages, or about 812 people out of every 100,000, with rates continuing to rise. Crohn’s disease can affect any part of the digestive tract, though it often involves the small intestine and the colon. Ulcerative colitis, a specific type of colitis, is limited to the colon and rectum.

While more than 200 genes may play a part in developing IBD, antibiotics have been identified as a risk factor, according to a study published earlier this year in Gut. Antibiotics are a small but important piece of the diagnostic puzzle, Dr. Adam Faye, IBD researcher, gastroenterologist, and lead author, told The Epoch Times.

“There’s some folks genetically primed for IBD,” he said. “We know it can run in families, and there’s probably a host of other environmental factors as well. I tell my patients to think of it like tinder. It’s just sitting there and waiting for one more spark, and it’s possible antibiotics will be that spark,” he added. 

His research found that people over 40 were most at risk, with the risk increasing with each round of antibiotics taken. The highest risk came from taking a group of antibiotics commonly prescribed to treat GI issues. Only one class of antibiotics was not associated with the later development of IBD in the study.

The Vicious Cycle of Antibiotics and IBD

Childhood use of antibiotics and repeated use of antibiotics have been clear risk factors for IBD for a decade, according to Dr. Robynne Chutkan, a gastroenterologist and author of “The Anti-Viral Gut.”

“The irony was it was the antibiotics that we used in Crohn’s that were shown to cause Crohn’s in some patients, things like metronidazole, flagyl, and cipro, which is a fluoroquinolone,” she told The Epoch Times. “It’s clear clinically, in what I’ve seen in my 33 years as a doctor, and in the scientific literature, and yet we still have very poor antibiotic stewardship.”

Moreover, IBD patients often require antibiotics for related complications, such as infections or as a precaution before surgery, potentially exacerbating symptoms or leading to worse infections like Clostridioides difficile (C.diff), a dangerous pathogen that can take over when gut flora are depleted after antibiotic use. Doctors treat C. diff with antibiotics, typically vancomycin.

Those with IBD have a 5-fold risk of getting sick from C. diff, which causes severe diarrhea and can even cause death. Those with IBD are 33 percent more likely to have a recurrent C. diff infection due to antibiotic resistance.

Limiting Antibiotic Use

Given the lack of treatments to directly address mucus production or correct the microbiome, experts recommend scrutinizing antibiotic use.

“Ideally we should only be taking antibiotics when needed,” Faye said. “There are oftentimes where we maybe have a viral infection or a cold and we either reach for an old antibiotic in our cabinet or we see urgent care and get a round of antibiotics. In those cases, if it’s not truly indicated, we may be doing more harm.”

Even bacterial infections—like urinary tract infections, strep throat, sinus infections, and ear infections—will often heal without antibiotics, Chutkan said. More doctors are beginning to adopt a “wait-and-see” approach to avoid overprescribing antibiotics.

“Let’s use the drugs more judiciously,” she said. “Physicians are really not thinking as they are solving these childhood problems that they are setting that child up for autoimmune diseases like Crohn’s and ulcerative colitis. That’s really, to me, the message.”

About one-third of antibiotic prescriptions written in medical settings are unnecessary, and frequent use erodes their effectiveness as bacteria adapt to defeat the drugs, according to The Pew Charitable Trusts, which monitors use of antibiotics in the United States.

Alternatives Exist

Dietary changes can often help not only IBD patients but also those who want to prevent the need for antibiotics, Dr. Anju Mathur of Angel Longevity Medical Center told The Epoch Times.

A physician and functional medicine provider, Mathur recommends removing gluten, dairy, sugar, and ultra-processed foods. That alone can reverse and prevent symptoms, she said.

For treating infections, Mathur often turns to herbs and supplements before resorting to antibiotics. Dozens of herbs and supplements can be effective, she noted.

“Plants have a lot of answers for human diseases, so we actually use those successfully, and very rarely do I have to give antibiotics to anyone.”