Probiotics are live bacteria that add more beneficial microorganisms to the gastrointestinal tract, while prebiotics are foods and supplements that promote the growth of microorganisms already residing in the gut. While both probiotics and prebiotics help improve and maintain intestinal health, their mechanisms of action and the sources in which you can find them are different. Consult your doctor before taking probiotics or prebiotics to determine which supplements are right for you.
Prebiotics and probiotics are both used to boost the health of the gut microbia, the beneficial bacterial colonies that live in the human digestive tract. The body contains more than 1,000 different varieties of bacteria, and the maintenance of microbes in the body is essential for overall health. Some of the specific jobs of gut bacteria include aiding the immune system in fending off invading microorganisms, helping the body digest specific foods, reducing gut inflammation and synthesizing necessary vitamins. The specific ratio of two groups of bacteria in the gut, Bacteroidetes and Firmicutes, may also play a role in obesity.
Probiotics typically include live colonies of the bacterial strains lactobacilli and bifidobacteria. Because probiotics are living organisms, excessive heat can destroy them and render them useless. When consumed, probiotics travel through the digestive tract and take up residence there.
Prebiotics are typically made up of nondigestible carbohydrates, such as inulin and galacto-oligosaccharides, compounds that can be broken down by gut bacteria but not by the human digestive tract. These compounds are extracted from food or supplements by bacteria residing in the gut as the food makes its way through the intestines and colon. The natural gut microbes use the prebiotics to enhance their own growth.
Both prebiotics and probiotics can be found naturally in some foods, and they are also frequently added to foods or consumed in supplement form. Common foods containing probiotics include yogurt, unpasteurized sauerkraut and kefir. Only products that are labelled as containing live and active cultures actually contain probiotics; frozen yogurt and processed foods made with yogurt do not.
Foods with prebiotic ingredients include onions, garlic, honey, bananas, soybeans, leeks and whole grains. Probiotic and prebiotic supplements are both available in tablet, capsule and powder forms for people who want to add more to their diets than food sources alone can provide.
Probiotics and prebiotics have complementary effects, so they are often used together. Eating foods that naturally contain probiotics and prebiotics is generally considered safe for most people. As an example, a meal containing yogurt, honey and whole-wheat toast introduces both probiotics and prebiotics into the body in a natural way. Talk to your doctor before starting synbiotics, commercially available supplements containing both prebiotics and probiotics.
- European Food Information Council: Gut Health: The Role of Bacteria, Probiotics and Prebiotics
- Nutrition Reviews: Human Gut Microbia and Its Relationship to Health and Disease
- Linus Pauling Institute: Probiotics and Prebiotics: Taking Care of the Bacteria That Live in Your Gut
- National Center for Complementary and Integrative Health: Oral Probiotics: An Introduction