Supplements for IBS: What Works?

Do fiber, probiotics, prebiotics, and other products ease irritable bowel syndrome?

Medically Reviewed by Louise Chang, MD on October 26, 2009
4 min read

Irritable bowel syndrome (IBS) is among the most common intestinal maladies and one of the most difficult to treat. No single remedy works for everybody, and there are few drugs created exclusively for IBS symptoms, which include abdominal pain, cramping, bloating, diarrhea, and/or constipation.

"I look at it this way: I don't have a lot of great things in conventional medicine to offer, so what I do have is in the realm of natural therapy," says Tieraona Low Dog, MD, a clinician and professor at the University of Arizona College of Medicine.

But that doesn't mean that all natural remedies touted as IBS fixes work, and in some cases, research results have been mixed. What really works? Here's what experts say.

Probiotics are microorganisms that supplement the gut's natural bacteria, helping to "balance" intestinal flora.

Why probiotics seem to work is still something of a mystery, but some studies suggest that probiotic supplements, especially those with a predominance of Bifidobacterium infantis, alleviate IBS symptoms like abdominal pain, bloating, and bowel movement irregularity.

Lawrence Schiller, MD, a gastroenterologist in Dallas, says he's comfortable recommending probiotic supplements to patients because probiotics don't do any harm and seem to help some of them.

But Schiller is skeptical of the products on the market; he says most studies of probiotics and IBS don't differentiate between bacterial strains and doses, a conundrum for the consumer who is faced with shelves full of probiotic-laced yogurts and milk in the market.

"The chances of going to the store and finding something viable and effective is very much a long shot," he says. "The best evidence for probiotics is with some of the combination products and some that contain bifida bacteria, not acidophilus or lactobilli."

Prebiotics are nondigestible food ingredients that stimulate growth and activity of microorganisms in the gut.

Prebiotics are naturally found in many foods, such as oatmeal and other whole grains, and many fruits and vegetables, including artichokes, asparagus, onions, and bananas.

Clinical studies have been small and few, and the results are mixed. One study showed that IBS patients given a combination of probiotics and prebiotics experienced a significant improvement in abdominal pain, bloating, and constipation; another study showed prebiotics had no effect.

Research into the role of fiber supplements in treating IBS symptoms is conflicting, with some finding no benefit, a few finding that added fiber to the diet causes bloating and gas, and a handful reporting that soluble fiber helps IBS patients with constipation and diarrhea.

A recent study found that psyllium, a soluble fiber, provided significant pain relief for IBS patients with constipation and/or diarrhea. Another found that psyllium has limited effect on constipation and abdominal pain.

Schiller says some of his IBS patients get relief from diarrhea and constipation with products containing psyllium, whether in the form of powder, tablets, breakfast bars, or cookies. There's no difference in their safety or effectiveness, he says.

Low Dog often prescribes psyllium for constipation, and if it aggravates constipation, which it can do until the body has enough of it and water, she'll add magnesium citrate to the mix to counteract the initial constipating effect of psyllium. She recommends powdered psyllium seed husks that can be mixed with liquid. "I also like psyllium because of its cardiovascular benefits. Any good fiber you can get, I like," Low Dog says.

Guar gum, also a soluble fiber that thickens food, shows some promise for IBS symptoms. David Rakel, MD, of the University of Wisconsin School of Public Health and Medicine, says he recommends supplements for patients to aid digestion.

Calcium polycarbophil, which is another soluble fiber, may help with diarrhea, constipation, abdominal pain, and bloating from IBS, according to a few studies. Schiller says that calcium polycarbophil supplements harden and soften stools, making it an effective supplement for mild diarrhea and constipation related to IBS.

Peppermint oil may lessen diarrhea symptoms by slowing fecal transit time.

Research is fairly solid on the subject, with one group of researchers concluding that peppermint oil is more effective and benign than drugs for GI spasm and could be a drug of first choice for IBS patients with mild constipation or diarrhea.

"Peppermint oil has better research than many pharmaceuticals for IBS," Rakel says.

For IBS patients who don't tolerate peppermint, a chamomile-pectin combination works well, Low Dog says. Chamomile helps to relax colon muscles, Rakel says.

Few, if any, studies exist that show a benefit for IBS patients from vitamin supplements.

"No vitamin that I know has been shown to be of therapeutic benefit in IBS," Rakel says.

Schiller says a balanced diet should provide the nutrients a body needs.