Probiotic Blend Shows Early Benefit for IBS Symptoms in New Study

A probiotic blend of Lactobacillus acidophilus LA-5 and Bifidobacterium animalis ssp. lactis BB-12 may ease symptoms of non-constipated irritable bowel syndrome (IBS) in adults, according to a randomized trial published last month in the Journal of Gastroenterology and Hepatology. The study tracked 200 adults with IBS over roughly 12 weeks, comparing a daily probiotic capsule against a placebo.

Participants were aged 18 to 65 and had IBS without constipation, with the most common symptoms including bloating, abdominal pain and diarrhea. They were randomly assigned to receive either the probiotic blend or a placebo twice daily for 84 days. About half of the participants in each group were diagnosed with IBS-D, while the remainder had IBS-M. In total, 99 received the probiotics and 101 received placebo.

By day 28, 19% of participants taking the probiotic reported symptom improvement versus 9% on placebo, a difference the researchers described as meaningful for a short trial. By day 56, 37% in the probiotic group reported improvement compared with 24% in the placebo group. At the end of the 12-week period, 41% of those taking the probiotic reported relief of symptoms compared with 37% in the placebo group.

Beyond symptom relief, the probiotic group showed a higher abundance of beneficial gut bacteria across nine genera by the study's end, while the placebo group had higher levels of bacteria considered potentially harmful. The researchers noted that these microbiome shifts may underlie the clinical improvements, though the exact mechanisms remain to be fully understood.

Lead author said the results provide the first evidence for the efficacy and safety of LA-5 and BB-12 as a probiotic blend for non-constipated IBS in adults. The study's design included 84 days of treatment, with participants maintaining daily symptom diaries and regular follow-up appointments to monitor outcomes. While the results are encouraging, the authors emphasized that longer trials are needed to confirm the durability of benefits and to assess long-term safety.

The broader context is that IBS has become more common in the United States and United Kingdom. Recent analyses suggest the condition has grown about 28 percent over the past decade, a rise some experts attribute to heightened awareness, evolving diagnostic criteria, and possible links to changes in the gut microbiome. Probiotic use in the United States is already relatively common, with estimates suggesting about one in 20 Americans take probiotic supplements regularly. LA-5 and BB-12 are widely available as supplements, with prices typically ranging from roughly $15 to $60 per month depending on brand.

Experts caution that probiotics are not a universal remedy for IBS and that individuals should discuss management options with healthcare providers. The new findings contribute to a growing body of evidence that targeted gut microbiome modulation may help some patients manage non-constipated IBS, but they also underscore the need for longer-term data and more diverse study populations to determine who benefits most.