Probiotics

What are they?

Probiotics are supplements of live bacteria. The bacteria most commonly used in probiotic supplements are Bifidobacterium bifidum and several types of lactobacilli including Lactobacillus acidophilus. Although we often hear about disease-causing or pathogenic bacteria, most of the bacteria found in the human body do not cause disease. In fact, they play a major role in helping the body break down and absorb nutrients in the gut. These “friendly” bacteria also protect the body from infection by simply consuming the same resources that disease-causing bacteria need to survive.

What do people with HIV use this supplement for?

To prevent and treat diarrhea due to gastrointestinal infections

HIV-positive people are vulnerable to a number of gastrointestinal infections that can cause diarrhea. An HIV-positive person who experiences persistent diarrhea should visit their doctor. If an infection can be identified, a more effective treatment can be started. Sometimes, however, the type of infection can’t be identified. Nevertheless, some HIV-positive people have used probiotics with success to treat unexplained diarrhea. Others have combined probiotics with other treatments to successfully treat known infections.

A study of immunocompromised mice showed that probiotics helped prevent infection with cryptosporidiosis, a parasite that often causes diarrhea in HIV-positive people. No human studies have been done however. Trials involving HIV-negative adults and children have been effective in preventing and treating some gastrointestinal infections, although a substantial number of other trials have found no benefit from probiotics.

Some of the drugs used to treat HIV and HIV-related infections can destroy the bacteria normally found in the gut. As a result, disease-causing bacteria, yeasts and parasites may flourish. Some people with HIV use probiotics to replace the “friendly” bacteria and prevent infection. Unfortunately, one of the few studies of probiotics in HIV-positive people did not show increases in friendly bacteria after three weeks of use. Although animals trials have produced some benefit, few human trials have shown a sustained increase in friendly bacteria after probiotic use. There is no reason to believe that probiotics are effective against diarrhea caused by antiretroviral therapy.

To help prevent vaginal yeast infections

Vaginal yeast infections are a common problem among HIV-positive women. After a yeast infection has been successfully treated, douching with a probiotic solution or applying unpasteurized yogurt to the vagina has reduced the recurrence of yeast infections in two small studies of HIV-negative women. No studies specific to HIV-positive women have been done.

To enhance immune function

There is currently little evidence to support this use of probiotics. Although some animals studies have shown that probiotics improve immune responses in the intestinal lining, trial results in humans have been less impressive. The few small studies that have been done have produced mixed results, and no consistent change in immune function has been observed from study to study.

Available forms and usage

Capsules containing probiotics can be purchased in health-food stores and some drug stores. Unpasteurized yogurt may also be purchased at many health-food stores. Both products should be refrigerated both at the store and in your home. The bacteria slowly die off over time so always look for a “best before” date and try to buy the freshest product possible. And be aware that the amount of live bacteria indicated on the label for each dose refers to the amount that was present on the day the product was manufactured.

Experts usually recommend doses of one to ten billion live bacterial cells. If you are taking antibiotics to treat or prevent infection, take your probiotics separately as long as possible after your dose of antibiotics.

If you are using probiotic capsules to make a douche, dissolve the contents of a capsule in 10 millilitres (two teaspoons) of water. Insert the solution into the vagina with a douche or a syringe (without the needle!).

Cautions and concerns

Although some question the safety of live bacterial supplements for people with weakened immunity, a 1998 study seems to suggest that at least one form of probiotic supplement is safe for HIV-positive people.

Overdoses of probiotic supplements may cause mild gastrointestinal upset, but quality probiotics are very safe at the doses described above. Some studies have shown that many probiotic supplements contain dead bacteria or bacteria other than those indicated on the label. Therefore, it’s important to buy fresh products from reputable manufacturers.

Many probiotics contain dairy products, so if you are lactose intolerant (difficulty digesting milk or milk products), use a non-dairy formula. But be aware that even non-dairy formulas may contain trace amounts of lactose.

References

Alak JI, Wolf B et al. Effect of Lactobacillus reuterion intestinal resistance to Cyrptosporidium parvum infection in a murine model of acquited immune deficiency syndrome. Journal of Infectious Diseases 175; 218-21.

de Roos NM, Katan MB. Effects of probiotic bacteria on diarrhea, lipid metabolism, and carcinogenesis: a review of papers published between 1988 and 1998. American Journal of Clinical Nutrition 2000 Jan;71:405-11.

Macfarlane GT, Cummings JH. Probiotics and prebiotics: Can regulating the activities of intestinal bacteria benefit health. British Medical Journal 1999 April;318:999-1003

Murray MT. Encyclopedia of Nutritional Supplements. Rocklin: Prima Publishing, 1996.

Wolf BW, Wheeler KB, et al. Safety and tolerance of Lactobacillus reuteri supplementation to a population infected with the human immunodeficiency virus. Food and Chemistry Toxicology 1998 Dec;36(12):1085-94.