The Truth About Probiotics and Your Gut (cont.)

Probiotics and the Immune System

There's also evidence that probiotics assist in maintaining a strong immune system. "In societies with very good hygiene, we've seen a sharp increase in autoimmune and allergic diseases," Guandalini tells WebMD. "That may be because the immune system isn't being properly challenged by pathogenic organisms. Introducing friendly bacteria in the form of probiotics is believed to challenge the immune system in healthy ways."

Probiotics May Benefit an Array of Ailments

Although evidence is still being gathered, researchers say there are enough data to rate the effectiveness of probiotics for several specific illnesses. In 2008, a panel of experts at Yale University reviewed the latest findings. They concluded that probiotics are most effective for:

  • Acute childhood diarrhea
  • Preventing antibiotic-associated diarrhea
  • Preventing pouchitis, an intestinal inflammation that can follow serious intestinal surgery
  • Regulating immune response
  • Treating and preventing eczema associated with cow's milk allergy

The Yale University panel of experts concluded that probiotics may be helpful in other ways, although the evidence so far is less convincing. These include:

Probiotics may also be useful in unexpected ways. A study published in 2010 suggests that probiotics may decrease the risk of common childhood problems such as ear infections, strep throat, colds, and diarrheal illness. The study included 638 children aged 3 to 6 in day care centers/schools. The children who drank a yogurt drink containing a probiotic were 19% less likely to come down with a common infection.

Cautions About Probiotics

For the most part, taking probiotics is very 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, probiotic supplements 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. More studies of probiotic use in young children and the elderly are needed.