The health benefits of eating yogurt, from helping build stronger bones to warding of infection, have been touted for years. Now, there's even more reason to reach for that container of yogurt from your grocer's shelf. Studies are showing that the probiotics  ("good bacteriam") found in yogurt can reduce diarrhea and that certain probiotics, for example, Bifidobacterium infantis 35624, may be useful in easing the symptoms of irritable bowel syndrome (IBS), according to a review of evidence published in the Journal of Clinical Gastroenterology.

Probiotics, derived from the Greek word meaning "for life," are live microorganisms, in most cases, bacteria, that are similar to the beneficial microorganisms found in the digestive system. They work by helping to break down foods that enter the digestive tract and fight off unhealthy bacteria and yeast.

There are a variety of microbes found in yogurt, most commonly, Streptococcus thermophilus and Lactobacillus bacterium, both of which create a barrier between harmful bacteria and the lining of the digestive tract, relieving digestive pain. Streptococcus thermophilus bacteria work by fighting lactic acid bacteria that can interfere with digestion and cause an upset stomach. Lactabacillus bacterium helps the body absorb nutrients, breaks down toxins and boosts metabolism, which improves digestion.

According to the National Center for Complementary and Alternative Medicine, researchers are now looking into whether probiotics can halt the development of "unfriendly" microorganisms, such as disease-causing bacteria, yeasts, fungi and parasites, and/or suppress their growth in conditions like IBS and infections with Helicobacter pylori (H. pylori), a bacterium that causes most ulcers and many types of chronic stomach inflammation.

How to Choose the Right Yogurt for You

Not all yogurt is created equal. Some types don't contain enough of the healthy bacteria you want. To be sure that you're getting plenty of the good stuff, look for the National Yogurt Association's Live and Active Cultures seal on the side of the container. This guarantees that the product contains at least 100 million bacteria per gram of yogurt at the time it is made. Other information to take into consideration:

  • Read the fat content-Yogurt comes in whole fat, low fat, nonfat and light. If you're looking to trim down, stock up on six-ounce cups that have no more than 90 calories for nonfat plain; 110 calories for low-fat plain; and 130 calories for flavored.
  • Look for nonstandard cultures-For additional health benefits, look for nonstandard cultures, such as Bifidobacterium longum, added to the ingredients.
  • Check the expiration date-As yogurts age, they lose their bacteria count, make sure the expiration date stamped on the container is several weeks in the future.