Not all bugs in our system are bad

How about some bugs in your dinner tonight?

Many people love them, the bacterial kind, that is. They use probiotics, an alternative medicine approach to supporting health.

Probiotics are often referred to as "friendly bacteria," though a range of microorganisms can qualify, including yeasts. Here's the idea: Some people think that live microorganisms in foods or supplements can boost the immune system and help treat certain conditions by replacing or increasing the body's natural supply of friendly bacteria when supplies are low.

For example, colonies of beneficial bacteria live in your intestines and help in the normal function of the gut. If you take antibiotics to fight an infection, the drugs kill both the problematic bacteria and the good guys. Eating yogurt with live bacterial cultures such as Lactobacillus bulgaricus or Streptococcus thermophilus, for example, may help replenish the gut's normal supply.

Other foods that contain probiotics include soy products such as miso and tempeh, soy beverages such as kefir, fermented milk such as buttermilk, and fermented cabbage such as sauerkraut and kimchee. The beneficial bugs are available in capsules, tablets and powdered forms, too, at natural foods stores and pharmacies.

Probiotics have been used since ancient times, but attempts to scientifically validate their usefulness are only beginning. The National Center for Complementary and Alternative Medicine, a unit of the National Institutes of Health, and the American Society for Microbiology in 2005 sponsored a conference on probiotics.

The group produced a report summarizing the evidence for the health benefits of probiotics. Among the benefits with the most scientific support:

• Treatment of diarrhea and irritable bowel syndrome. Diarrhea caused by rotavirus was the condition for which there was the greatest evidence of efficacy.
• Prevention and treatment of urinary tract infections, female genital tract and reduction of the risk for recurrence of bladder cancer.
• Shortening the amount of time it takes for the body to recover from an intestinal infection caused by Clostridium difficile bacteria, and prevention and treatment of infection that follows surgery to remove the colon.
• Prevention and treatment of eczema in children.

More information about probiotics is available online from the National Center for Complementary and Alternative Medicine at http://nccam.nih.gov/health/probiotics/.

More studies are needed before firm recommendations can be made about probiotics. A strong placebo effect may be at play where benefits from probiotics are concerned, according to NCCAM. In other words, it's possible that benefits are all in your head.

Still, there doesn't appear to be much risk from using probiotics, though their use hasn't been studied well, especially in young people, older adults and people with depressed immune systems. For healthy adults, the primary side effects are likely to be gas or bloating.

If you use probiotics and are being treated for a medical condition, be sure to let your health care provider know what you are eating or taking, especially if you are using supplemental forms of probiotics such as capsules, tablets or powders.

On the other hand, foods such as sauerkraut, miso and tempeh aren't likely to pose much risk. If you eat yogurt or drink kefir (a cultured yogurt drink), buy nonfat varieties to limit your saturated fat intake. Miso and pickled vegetables such as kimchee and sauerkraut are high in sodium, so if you include them in your diet, balance your sodium intake by eating more low sodium foods such as fresh vegetables and fruit.

And embrace the promise of probiotics, because not all bugs are bad.