What may help: Saccharomyces boulardii.
The evidence: “It’s pretty modest,” notes the University of Washington’s Lynne McFarland. (She was scientific director for the company that manufactures the S. boulardii supplement Florastor from 1988 to 2001.) In the two biggest studies, researchers gave 5 billion to 20 billion live S. boulardii cells or a placebo to 3,039 Austrian tourists every day for three weeks, starting five days before they traveled to the tropics, North Africa, the Middle East, or the Far East.
Six of every 15 tourists who took the placebo reported getting diarrhea while they were away, compared with five of every 15 who took the yeast. And the researchers weren’t even certain about that slight benefit, since only about a third of the participants completed the study.
“Tourists are probably the worst subjects for a clinical trial,” explains McFarland. “You’re more interested in having fun, you’re trying new foods, and you don’t exactly take every dose you’re supposed to.”
The bottom line: Don’t count on Saccharomyces boulardii—or any other probiotic—to shield you from travelers diarrhea.
Source: Travel Med. Infect. Dis. 5: 97, 2007.
Other relevant links:
- Our guide to probiotic supplements. See: Are Probiotic Dietary Supplements Worth Taking?
- This probiotic may help people with IBS. See: Can Dietary Supplements Help People with Irritable Bowel Syndrome?
- Should you take a daily multivitamin? See: Dietary Supplements: Are Multivitamins Useless?