Fructooligosaccharides (FOS) refer to a class of non-digestible carbohydrates or sugars that occur naturally in a wide variety of foods throughout the plant kingdom. Since they are non-digestible, they pass through the human digestive virtually unchanged. When the fructooligosaccharides reach the colon, they are used by the good or beneficial bacteria found there (known as bifidobacteria or bifidus) for growth and multiplication. A healthy population of these beneficial bacteria in the digestive tract enhances the digestion and absorption of nutrients, detoxification and elimination processes, and helps boost the immune system.
Since fructooligosaccharides are non-digestible, they provide almost no calories and are thus used as substitute sweeteners. Fructooligosaccharides have approximately one-half the sweetness of sugar. They are also being added to a variety of food products because they provide a combination of sweetness and low calories plus the additional health benefits that have been mentioned.