What Are Probiotics & Prebiotics?

The idea of using bacteria to improve human health was first introduced by Elie Metchnikoff in the early 1900s, but was not fully embraced by the medical community until recently. With the increasing incidence of antibiotic-resistant infections, additional therapies for prevention and treatment of infection are needed. Probiotics and prebiotics are two methods of preventing and fighting infections. Probiotics are live bacteria that can protect you from infections, while prebiotics are food sources for probiotics and the healthy bacteria that are naturally present in your body.

Healthy Bacteria

Your body is home to several billion bacteria. Many of these bacteria have a positive impact on your health, and the majority of these reside in your intestines. Good bacteria boost your immune system and form a barrier in your intestines that protects you from harmful bacteria and viruses. They also help you digest food. The community of bacteria in your intestines started when your mother passed some of her bacteria to you at birth. As an infant, these bacteria informed your immune system so it could distinguish between helpful and harmful microorganisms. Your intestinal bacteria also help you digest food.

Probiotics

Any live microorganism that can improve your health is considered a probiotic by the World Health Organization. Bacteria available in probiotic foods and supplements have been studied by the scientific community and selected for their ability to survive passage through the stomach so they can grow in your intestines. Common probiotics include Lactobacillus and Bifidobacterium.

Prebiotics

Prebiotics are food sources for good bacteria. They are substances that generally cannot be digested by your body, but are excellent sources of nutrition for the bacteria in your intestines. Most prebiotics are carbohydrates, such as inulin and fructooligosaccharides. Prebiotics enhance the growth of healthy bacteria already in the intestines, or encourage and maintain the growth of a probiotic. The use of probiotics and prebiotics in combination is called synbiotics. An article in "The American Journal of Clinical Nutrition" by David Collins and Glenn Gibson suggests that synbiotics provide the best conditions for growth of a probiotic in the intestines, since the probiotic is administered along with its preferred food source.

Treating and Preventing Disease

Probiotics, prebiotics and synbiotics are the focus of many scientific studies to determine their potential for treating and preventing disease. A 2007 study in "Travel Medicine and Infectious Disease" concluded that probiotics are an effective method for preventing traveler's diarrhea. Probiotics have also been used to treat cases of diarrhea associated with antibiotic use. Initial clinical trials show promise for the use of prebiotics and synbiotics to treat inflammatory bowel disease.