'I've been taking expensive probiotics every day' — the supplement may not be doing what you think

If you have been faithfully taking probiotics but are not noticing any real difference in your digestive health, it may be worth ditching the supplements and simply changing your diet instead.

The Washington Post reported Thursday that there is little evidence probiotic supplements improve gut health in healthy people. Citing research by Kira L. Newman, a clinical assistant professor at the University of Michigan Medical School published in the journal Clinical Gastroenterology and Hepatology, the Post said that "for most people, probiotics may provide a sense of agency, but may not necessarily deliver the benefits users are looking for." Some research has even found that in certain cases, probiotic supplements can disrupt the composition of the gut microbiome — the complex community of microorganisms living in the digestive tract.

The research found that while probiotic supplements contain microorganisms capable of activating the gut, their numbers are limited and they often fail to function effectively. Some studies have found that probiotic supplements actually reduce microbiome diversity. A Stanford University research team conducted a clinical trial in which adults with metabolic syndrome took probiotic supplements for 18 weeks. Some participants showed improvements in blood pressure and triglyceride levels, but others saw their blood sugar and insulin levels worsen.

One reason probiotics often fall short of expectations is that they struggle to reach the intestines intact after passing through the digestive tract. The research team pointed to fiber-rich foods — fruits, vegetables and whole grains — as a more promising alternative. Newman said foods such as fruits, vegetables and whole grains all support a healthy microbiome, adding that dietary fiber acts as fuel for the gut's microbial community.

"Most of our guidelines for gastrointestinal health and microbiome-related conditions do not recommend probiotics on a routine basis," Newman said. "What we consistently recommend across many conditions is a diet rich in fruits, vegetables and whole grains."

Fiber stands apart from probiotics not only because it feeds the microbiome, but also because it arrives in the intestines undamaged. The human body lacks the enzymes needed to break down fiber, so it passes through intact. Gut microorganisms then convert fiber into short-chain fatty acids and other compounds that help reduce inflammation, improve blood sugar levels and stimulate the production of appetite-suppressing hormones.

Newman also said that fermented foods — such as yogurt, kimchi and kefir — can alter the composition of the gut microbiome and promote gut health. Research suggests that eating fiber-rich plants alongside fermented foods can increase microbiome diversity and help crowd out harmful pathogens.