Prebiotics are nondigestible or partially digestible food ingredients that stimulate the growth of healthy bacteria in the colon and thus promote better overall health. Along with probiotics, which are live microbial organisms that support gastrointestinal health, prebiotics are considered functional foods, so-called because they provide health benefits that go beyond basic nutrition. Although they are also available in supplement form, prebiotics occur naturally in a number of common foods with high fiber content.
Meet the Prebiotics
Making up the prebiotic family are several fibrous elements that occur naturally in the foods you eat. The two most common subtypes of prebiotics are the closely related inulins and fructo-oligosaccharides, or FOS, both of which pass through the small intestine without being digested or absorbed, making them excellent prebiotics. Once these prebiotics reach the colon, they stimulate the growth of bifidobacteria -- probiotics that occur naturally in the human gastrointestinal tract -- and other beneficial microorganisms. Another subtype within the prebiotic family is that of the galacto-oligosaccharides, or GOS, which are synthesized from lactose – a complex sugar present in cow’s milk – by enzymatic activity within the body. GOS are also present in several nondairy foods.
Symbiosis of Prebiotics, Probiotics
Research has established strong evidence of a symbiotic relationship between prebiotics and probiotics. The presence of prebiotic foods in the gut creates a suitable environment in which probiotic microorganisms can flourish, while the presence of probiotics aids the gut in digesting the complex prebiotic carbohydrates. Consuming prebiotic foods in conjunction with probiotic supplements can amplify the benefits of both.
Foods Rich in Prebiotics
Foods that contain high levels of inulin and FOS include asparagus, burdock, chicory, dandelion root, Jerusalem artichoke, leeks and onions, according . Although enzymes can convert the lactose from milk into GOS in the human body, these prebiotics also occur naturally in several plant-based foods. These foods include grains, legumes and cruciferous vegetables such as broccoli, Brussels sprouts, cabbage, cauliflower, collard greens, kale, radish and rutabaga.
Other Health Benefits
Although they are best known for promoting the growth of beneficial bacteria or probiotics in your gastrointestinal tract, prebiotics have some additional benefits that make them a welcome addition to a healthy diet. Prime among these benefits is increased calcium absorption, which is particularly important for the maintenance of healthy bones and teeth. Given prebiotics’ support of gastrointestinal health, medical researchers are also studying prebiotics to see how they may be useful in preventing or treating inflammatory bowel disease and colon cancer.
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- Frontiers in Immunology: The Role of Probiotics and Prebiotics in Inducing Gut Immunity; Angelica T. Vieira, et al.
- Gastroenterology Research and Practice: Probiotics, Prebiotics, and Synbiotics - Gut and Beyond; Usha Vyas, Natarajan Ranganathan
- Nondigestible Carbohydrates and Digestive Health; Teresa M. Paeschke and William R. Aimutis