The term prebiotic, not to be confused with probiotic, is a new term for polysaccharides such as inuline, galactooligosaccharides, and fructooligosaccarides (FOS). We cannot digest prebiotics because our digestive systems do not produce the correct enzymes. Prebiotics are therefore members of the fibre group.
Inuline: This polysaccharide is named after the Horse-heal plant (Inula helenium), which contains high levels of inuline in its roots. Other herbs, such as chicory (Cichorium intybus) and Jerusalem artichoke (Helianthus tuberosa), contain high levels of inuline. Inuline is made up of long chains of fructose and a small amount of glucose. It is broken down by lacto- and bifido- bacteria in the intestines and in the process produces a number of short-chained organic acids. These acids lower the intestinal pH (increase the acidity), strengthen the intestinal wall, and make it harder for health detrimental bacteria to grow in the intestines.
Galactooligosaccharides: These polysaccharides are composed of galactose and glucose. They are found naturally in peas, beans, and other pod plants.
Fructooligosaccarides: These polysaccharides are composed of many glucose units. They are found naturally is chicory, artichoke, onion, asparagus, and more.
Fruit and vegetables generally contain large amounts of prebiotics. Studies have shown that people who eat supplements of 15 g fructooligosaccarides daily can increase the number of beneficial bacteria in the intestines ten fold while decreasing the number of health detrimental bacteria.
People with an optimal amount of beneficial intestinal bacteria are better protected again digestive infections such as those caused by campylobacter, coli bacteria, salmonella, and listeria than people who have low levels of beneficial bacteria.
Prebiotics are often added to probiotic supplements (lactic acid bacteria) to stimulate the growth of these bacteria and their activity in the intestines. Popularly described, this is like giving the bacteria a lunchbox.
Prebiotic supplements do not add calories to the diet and normally have no side effects. Large daily doses can cause gas and have a slight laxative effect.
Also see: Fibre and Probiotics-Lactic acid bacteria
