Cautions About Probiotics
For the most part, taking probiotics is safe and causes few side effects. “People in cultures around the world have been eating yogurt, cheeses, and other foods containing live cultures for centuries,” says Martin Floch, MD, a professor of gastroenterology at Yale University, co-author of Probiotics: A Clinical Guide, and a consultant for the Dannon Company.
Still, probiotics may be dangerous for people with weakened immune systems or serious illnesses. One study found that patients with severe pancreatitis who were given probiotics had a higher risk of death.
Which Is Better, Probiotic Foods or Supplements?
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 organisms to grow in the intestines. Experts say the effective dose varies, 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 reuteri 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 drugs because probiotics are in the same category as food and supplements.
“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 say the name of the precise probiotics 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.