The idea of tossing down a few billion bacteria a day for your health might seem—literally and figuratively—hard to swallow. But the May issue of Harvard Women’s Health Watch reports that a growing body of scientific evidence suggests that you can treat and prevent some illnesses with supplements containing certain kinds of health-promoting bacteria, called probiotics (meaning “for life”).

An estimated 100 trillion microorganisms inhabit every normal, healthy bowel, where they keep pathogens (harmful microorganisms) in check, aid digestion and nutrient absorption, and contribute to immune function. If these gut-dwelling bacteria become depleted—usually because of disease, stress, poor diet, or medications like antibiotics—health problems can result.

According to Harvard Women’s Health Watch, probiotic therapy has been best studied for the treatment of diarrhea. It may also help people with Crohn’s disease, irritable bowel syndrome, and other gastrointestinal problems. Probiotics that help restore the balance of microflora in the vagina may be useful in treating such common female urogenital problems as bacterial vaginosis, yeast infection, and urinary tract infection. More study is needed to know which probiotic strains work best for which conditions.

Harvard Women’s Health Watch suggests that people considering probiotics keep these points in mind:

• The recommended doses range from 1 billion to 10 billion colony-forming units (CFU)—the amount contained in a capsule or two—several days per week.
• A daily supplement for one to two weeks may improve conditions such as infectious or antibiotic-related diarrhea.
• The microorganisms in probiotic supplements need to be alive when you take them (or when they’re freeze-dried for capsules). They may die on exposure to heat, moisture, or air. Some require refrigeration.

Also in this issue:

• Aspirin therapy for heart health
• Sleep and obesity
• 10 tips for improving memory
• A doctor answers: Is snoring bad for me? Is Zelnorm safe?