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In this Article

• Introduction to probiotics
• What is important to know about probiotics?
• What are probiotics, and which foods contain probiotics?
• What are the health benefits of probiotics?
• Do probiotics actually work?
• What are the side effects and risks of probiotics?
• Is there anything to take into consideration when taking probiotics?
• What research is being done on probiotics?
• Where can a person get more information about probiotics?
• Probiotics Index

Uses for health purposes

There are several reasons that people are interested in probiotics for health purposes.

First, the world is full of microorganisms (including bacteria), and so are people's bodies -- in and on the skin, in the gut, and in other orifices. Friendly bacteria are vital to proper development of the immune system, to protection against microorganisms that could cause disease, and to the digestion and absorption of food and nutrients. Each person's mix of bacteria varies. Interactions between a person and the microorganisms in his body, and among the microorganisms themselves, can be crucial to the person's health and well-being.

This bacterial "balancing act" can be thrown off in two major ways:

1. By antibiotics, when they kill friendly bacteria in the gut along with unfriendly bacteria. Some people use probiotics to try to offset side effects from antibiotics like gas, cramping, or diarrhea. Similarly, some use them to ease symptoms of lactose intolerance -- a condition in which the gut lacks the enzyme needed to digest significant amounts of the major sugar in milk, and which also causes gastrointestinal symptoms.

2. "Unfriendly" microorganisms such as disease-causing bacteria, yeasts, fungi, and parasites can also upset the balance. Researchers are exploring whether probiotics could halt these unfriendly agents in the first place and/or suppress their growth and activity in conditions like:

• Infectious diarrhea



• Irritable bowel syndrome



• Inflammatory bowel disease (e.g., ulcerative colitis and Crohn's disease)



• Infection with Helicobacter pylori (H. pylori), a bacterium that causes most ulcers and many types of chronic stomach inflammation



• Tooth decay and periodontal disease



• Vaginal infections



• Stomach and respiratory infections that children acquire in daycare



• Skin infections

Another part of the interest in probiotics stems from the fact there are cells in the digestive tract connected with the immune system. One theory is that if you alter the microorganisms in a person's intestinal tract (as by introducing probiotic bacteria), you can affect the immune system's defenses.