The Truth About Probiotics and Your Gut (cont.)

Are Probiotic Supplements or Foods Best?

Probiotics come in many forms, including powders, tablets, capsules, and foods such as yogurts and dairy drinks. The form you take them in doesn't matter, experts say, as long as it contains enough live organisms to begin growing in the intestines. Experts say the effective dose varies widely, from as little as 50 million to as many as 1 trillion live cells per dose.

Specific probiotic organisms appear to be useful for particular illnesses, however. The bacteria Lactobacillus GG and the yeast Saccharomyces boulardii have been shown to be helpful for infectious diarrhea in children, for example. "But there's no evidence that Lactobacillus acidophilus, which is used in many commercial yogurts, has any benefits for diarrhea," says Floch.

Advice on Choosing a Probiotic Supplement

The FDA does not regulate probiotics as it does prescription medications because probiotics are in the same category as food and supplements. With growing evidence for their effectiveness, however, the FDA is reviewing their status and may regulate them more closely in the future.

"For now, the best advice is to choose products from well-known companies, especially those that have been tested in research studies," Guandalini says. Reliable products should indicate the name of the precise probiotic organisms they contain, as well as how many organisms a single dose provides. Many products also provide information on the scientific studies they use for their recommendations.


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Stefano Guandalini, MD, professor of pediatrics and gastroenterology, University of Chicago Medical Center.

Martin Floch, professor of gastroenterology, Yale University School of Medicine, New Haven, Conn.; co-author, Probiotics: A Clinical Guide.

Reviewed by Louise Chang, MD on June 09, 2010

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Last Editorial Review: 6/9/2010 8:11:39 PM