The business of beneficial bacteria seems to be booming, with the word "probiotics" showing up on labels of everything from supplements to yogurt to granola bars.

Probiotics are "friendly bacteria" that are similar to organisms that occur naturally in the digestive tract. Certain strains or types of probiotics have been linked to all sorts of health benefits, from helping with irritable bowel syndrome and traveler’s diarrhea to boosting the immune system. They're sometimes used with antibiotics to combat the diarrhea that may result from taking antibiotics.

As the supermarket invasion of probiotic products kicks into high gear, you may have some questions about how to buy and use them. Here are some answers to five common questions about probiotics and products that contain them.

1. Does the FDA Regulate the Term "Probiotics"?

The NIH's National Center for Complementary and Integrative Health defines probiotics as "live microorganisms that are intended to have health benefits when consumed or applied to the body."


So far, the U.S. Food and Drug Administration (FDA) has approved no specific health claims for probiotics. Further, the amounts of probiotics that studies have found to be beneficial vary from strain to strain and condition to condition.

The FDA requires dietary supplements to be produced in a quality manner, to be free of contaminants or impurities, and to be accurately labeled. Many probiotic researchers are hoping these regulations will improve the quality of probiotic supplements in the United States. 


2. Which Strains of Probiotics Should I Look For?

Studies have shown different strains of probiotics to provide different benefits. If you're looking for dietary support for the immune system, probiotic microbiology consultant Mary Ellen Sanders, MS, PhD, suggests looking out for:

  • Bifidobacterium lactis HN019. This strain helps modulate some aspects of the immune system in older people (it's sold as an ingredient for dairy and supplement products).
  • Lactobacillus reuteri ATCC55730 (available in BioGaia Gut Health products).
  • Lactobacillus rhamnosus GG (LGG) (in Culturelle capsules).
  • Lactobacillus casei DN-114 001 (in DanActive products).
  • Bifidobacterium lactis Bb-12 (available in Fage yogurt). Use this uncooked for best results.

And if you want to provide dietary support for diarrhea associated with antibiotic use, Sanders suggests looking for:

  • S. cerevisiae (S. boulardii) (found in Florastor powder) 
  • Lactobacillus rhamnosus GG (LGG)  (Culturelle capsules)
  • Lactobacillus casei DN-114 001 (in DanActive products)
  • Lactobacillus acidophilus CL1285 plus Lactobicillus casei Lbc80r (available as BioK + CL1285 fermented milk, BioK + CL1285 soy milk, and capsules)

3. What Should I Look for on the Label of a Food Containing Probiotics?

The first thing you want to look for is the full probiotic name, which includes the genus, species, and then the strain. Many products containing probiotics list only the genus and species on the package, such as "bifidobacterium lactis." 

You might want to check out the website of the company that sells the product. It may tell you more about:

  • The strain used in the product
  • How much of the probiotic each serving of the product contains
  • The research that suggested a health benefit from the probiotic in question, and the amount of probiotic that was used in the research

4. Are probiotic supplements worthwhile?

Sanders believes that probiotics can be effective when consumed either in food or pill form.

"Food sources of probiotics have the advantage in that they offer good nutrition along with the probiotic bacteria," she says. Still, supplements can be more convenient for some people and may provide higher levels of probiotic, depending on the product in question, she says.

"The most important consideration is that the product -- food or supplement -- deliver adequate numbers of efficacious probiotics for your needs," Sanders says.

5. Are Probiotics Safe for Everyone?

People who are acutely ill or who have a compromised immune system should be cautious about consuming probiotic products and supplements. Researchers are still trying to figure out which types of disease and illnesses should preclude the use of probiotics.

Although no studies have shown probiotics to be harmful in healthy people, Barry Goldin, MS, PhD, a professor at Tufts University School of Medicine, says terminally ill cancer patients and people with conditions with the potential for leaky bowels, including acute pancreatitis, should NOT consume probiotics.

Just to be safe, tell your doctor if you’re thinking about taking (or eating) probiotics regularly.

Show Sources


Mary Ellen Sanders, MS, PhD, consultant in probiotic microbiology; host, web site with the California Dairy Research Foundation.

Barry Goldin, MS, PhD, professor of of family medicine and community health, Tufts University School of Medicine.

FDA news release, June 22, 2007.

Belkaid Y., Oldenhove, G., Immunity, 2008 vol. 29 (3) pp 362-371.

Douglas, L.C., Sanders, M.E, Journal of the American DieteticAssociation, March 2008, vol. 108 (3), pp 510-521.

D’Souza, A.L., Hickson, M., Muthu, N., et al, British Medical Journal, July 14, 2007; vol. 335 (7610) p. 80.

Alberda, C., Gramlich, L., Meddings, J., et al, American Journal of Clinical Nutrition, March 2007, vol. 85 (3), pp 816-823.

Tublius, P., Stan, V., Zachrisson, A., Environmental Health, May 2005, vol. 4 (25).

Boyle R.J., Robins, R.M., Tang, M., American Journal of Clinical Nutrition, June 2006, vol. 83 (6), 1256-1264.

Douglas, L.S., Sanders, M.E., Journal of the American Dietetic Association, March 2008, vol. 108 (3). pp 510-521.