You don't necessarily need probiotics — a type of "good" bacteria — to be healthy. However, these microorganisms may help with digestion and offer protection from harmful bacteria, just as the existing "good" bacteria in your body already do.
Prebiotics are nondigestible carbohydrates that act as food for probiotics. When probiotics and prebiotics are combined, they form a synbiotic. Fermented dairy products, such as yogurt and kefir, are considered synbiotic because they contain live bacteria and the fuel they need to thrive.
Probiotics are found in foods such as yogurt, while prebiotics are found in whole grains, bananas, onions, garlic, honey and artichokes. In addition, probiotics and prebiotics are added to some foods and available as dietary supplements.
Although more research is needed, there's encouraging evidence that probiotics may help:
- Treat diarrhea, especially following treatment with certain antibiotics
- Prevent and treat vaginal yeast infections and urinary tract infections
- Treat irritable bowel syndrome
- Reduce bladder cancer recurrence
- Speed treatment of certain intestinal infections
- Prevent and treat eczema in children
- Prevent or reduce the severity of colds and flu
Side effects are rare, and most healthy adults can safely add foods that contain prebiotics and probiotics to their diet. If you're considering taking supplements, check with your doctor to be sure that they're right for you.
Sep. 15, 2011
See more Expert Answers
- An introduction to probiotics. National Center for Complementary and Alternative Medicine. http://nccam.nih.gov/health/probiotics. Accessed July 26, 2011.
- Kligler B, et al. Probiotics. American Family Physician. 2008;78:1073.
- Sartor RB. Probiotics for gastrointestinal diseases. http://www.uptodate.com/home/index.html. Accessed July 26, 2011.
- Leyer GJ, et al. Probiotic effects on cold and influenza-like symptom incidence and duration in children. Pediatrics. 2009;124:e172.
- Vouloumanou EK, et al. Probiotics for the prevention of respiratory tract infections: A systematic review. International Journal of Antimicrobial Agents. 2009;34:197.e1.
- Douglas L, et al. Probiotics and prebiotics in dietetics practice. Journal of the American Dietetic Association. 2008;108:510.