Probiotics for IBS: The Case for and Against 'Good' Bacteria
The use of probiotics has become increasingly popular in recent years, but whether they actually help people with irritable bowel syndrome remains questionable.
If you are one of the 25 to 45 million Americans who suffers from irritable bowel syndrome (IBS), an intestinal disorder that causes pain, cramping, or constipation, diarrhea, or both, you know how important it is to find a treatment for symptom relief. Although no one knows for sure what causes IBS, one theory is that symptoms are caused by an overgrowth of harmful bacteria in the intestinal tract. One solution might be to increase the number of good bacteria.
Probiotics are live microorganisms that are considered good bacteria. They can be found in foods like yogurt, sauerkraut, and kimchi, as well as in some beverages and dietary supplements. The American Gastroenterological Association (AGA) estimates that 3.9 million American adults use some form of probiotics or prebiotics (plant fibers that promote the growth of healthy gut bacteria). It’s estimated that Americans collectively doled out over $63 billion on probiotic products in 2021, according to Precedence Research.
If you’re taking probiotics for IBS, however, it continues to be controversial whether it’s money well spent.
What the Research Says About Probiotics and IBS
“The AGA does not recommend that somebody start taking probiotics for IBS,” says Geoffrey A. Preidis, MD, PhD, an assistant professor of pediatrics at Baylor College of Medicine in Houston and a co-author of the AGA’s first and only Clinical Practice Guidelines on the Role of Probiotics in the Management of Gastrointestinal Disorders in adults and children. The guidelines serve as an evidence-based resource for healthcare providers who are deciding how to treat patients with IBS and other gastrointestinal disorders. “We weren’t able to make a recommendation because there is a knowledge gap. There’s not enough information in the published literature for the use of probiotics in general or any particular strain for adults or children with IBS,” Dr. Preidis says.
From the research available on probiotics and IBS, Preidis and his team identified 1,600 abstracts of published studies. From there, they analyzed 55 published studies that met their inclusion and exclusion criteria. The 55 studies assessed more than 5,300 patients with IBS. Collectively, the 55 trials tested 44 probiotic species, strains, or combinations of species and strains.
But the studies lacked consistency. None of the studies tested the exact same probiotic formulation in exactly the same way or measured an outcome, such as abdominal pain, exactly the same. Different strains of the same species of probiotics can have very different effects, even the opposite effect, Preidis says.
“If we are going to recommend that clinicians prescribe specific probiotics to specific patient groups, you want to see a beneficial effect repeated across numerous published studies done in multiple, different geographic regions with different populations of patients,” Preidis says. And that didn’t happen. In the 55 studies, most probiotic products were tested in just one study.
Moreover, probiotics, although sold over the counter and generally regarded as safe, aren’t risk-free. “However, as living organisms, probiotics can potentially move from the intestine to the bloodstream, causing a serious condition known as sepsis, which is rare in healthy people but the risk can be higher in those with a weakened immune system,” Preidis says, warning of the potential that probiotics can be contaminated during manufacturing.
“For people with IBS, there is simply no good solid evidence that probiotics provide a benefit,” Dr. Preidis says. Additionally, the U.S. Food and Drug Administration has not approved the use of probiotics as a treatment for any disease.
“We do not recommend that somebody start taking probiotics or use them on a routine basis for IBS,” Predis says. The current AGA clinical guidelines don’t even suggest experimenting with probiotic products — in other words, conducting your own informal research — to see if probiotics might work for you, he says.
Using Probiotics Under a Doctor’s Supervision
Still, if you have IBS and you like the idea of probiotics, talk with your doctor about the risks and benefits. Despite the AGA’s position on probiotics and IBS, gastroenterologists individually may still recommend them.
“I’m a believer,” says Lisa Ganjhu, DO, a gastroenterologist at NYU Langone Health and clinical associate professor at the NYU Grossman School of Medicine in New York City. “If patients complain about bloating or any gastrointestinal complaint, I will usually start them on a probiotic if they’re not already taking one.” She also encourages her patients with IBS to consume probiotic-containing foods, such as yogurt with live, active cultures and pickled foods like kombucha (fermented tea), kimchi (Korean-style spicy, fermented cabbage), kefir (a yogurt drink), and sauerkraut (pickled cabbage).
Fermented foods use microorganisms, such as yeast and bacteria, during processing. As a result of the fermentation process, they contain beneficial live bacteria that may make their way to your large intestine during the digestion process to ultimately improve the health of your immune system.
In a study published in The Journal of Nutrition, which analyzed 19 studies in which subjects consumed fermented foods or not, “we determined that the consumption of fermented foods may change the amounts and types of good bacteria that live in the human gut,” says Karin B. Michels, PhD, a professor in the department of epidemiology at the University of California in Los Angeles, who led the study.
Still, probiotics aren’t for everyone. “Doing too much can cause harm. I see a number of patients on a probiotic who say they feel horrible. When I ask them what they’re taking, they mention a probiotic with 32 or 64 strains of bacteria that’s super expensive. If you talk to them long enough, they’ll say they started to feel bad after they started to take the probiotic,” Dr. Ganjhu says. And due to the risk of sepsis, certain people should avoid probiotics, such as those with autoimmune or immunity disorders, she says.
Similarly, Dr. Michaels recommends regularly consuming fermented foods you can tolerate well. Yogurt or kefir are entry-level fermented foods to add to your repertoire. If you’re not a fan of yogurt made from milk, nondairy soy or nut-based yogurt will do the job, she says. They contain the same amounts of live bacteria as yogurt made from dairy.
If yogurt goes over well, feel free to graduate to other fermented foods, such as kombucha, kimchi, or sauerkraut, which is a probiotic powerhouse that Michels describes as “full of healthy bacteria.” But cooking sauerkraut can kill the probiotics if cooked at a temperature above 115 degrees F, so consider adding it to your dish at the end of cooking.
Overall, if you have IBS and you’re considering taking a probiotic supplement, Ganjhu recommends keeping it simple and sticking with a probiotic with no more than five strains of organisms listed on the label. Give a probiotic about six weeks or so to see if it works. “If you’re feeling great, feel free to keep going or take a break. In theory, the good bacteria should keep replicating in your microbiome and working for you,” Ganjhu says. If probiotics or a probiotic food makes you feel worse, stop consuming them.
And save your money if your IBS isn’t causing symptoms. “If you’re not thinking about your belly and digestion, then you’ve got a happy belly,” Ganjhu says. “That means your microbiome is balanced, and there’s no reason to take a probiotic. It’s not like an insurance policy. In fact, what’s strong enough to cause good can become strong enough to cause problems.”
Additional reporting by Sandra Gordon.