Probiotics are live microorganisms found in certain yogurts and yeasts. They can help the body's immune and digestive systems. Probiotics, which means "for life," have been used for centuries as natural components in health-promoting foods.

Spending on probiotic supplements nearly tripled from 1994 to 2003. Probiotic foods such as Dannon’s heavily advertised Activia and Danactive yogurts have helped the category grow between 12 percent and 15 percent in 2007.

Though studies are in the works, there is limited evidence supporting some uses of probiotics, including its treatment for some health conditions. But researchers and nutritionists agree that probiotics support overall good health and benefit your immune system.

What else should you know about probiotics?

•    Supplements are manufactured and regulated by the U.S. Food and Drug Administration (FDA) as foods, not drugs, and considered safe.
•    Side effects, if they occur, are mild and include gas or bloating. People with underlying health conditions, or who are also taking antibiotics, should check with their doctors regarding any possible drug interference or side effect.
•    Lactic acid bacteria are the largest group of probiotic bacteria in the intestine. Yeast also is a probiotic.
•    The manufacture of probiotic supplements is not standardized, so you may purchase a different form in a health food store or grocery than is used in research.

Researchers are examining issues such as:

•    How probiotics interact with the body.
•    Therapeutic effect,
•    The impact on illnesses including allergies, cancer, gastrointestinal disorders and lactose intolerance,
•    And how to best administer probiotics as treatment.

Sources: Nutrition Business Journal; National Center for Complementary and Alternative Medicine (NCAM), a division of the National Institutes of Health; usprobiotics.org.