FOS or fructooligosaccharides is a prebiotic that is designed to promote the proliferation of probiotics in the gastrointestinal tract, which ultimately supports the immune system by aiding in digestive comfort. High concentrations of FOS can be found in bananas, tomatoes, wheat, asparagus, garlic, and onions. Dietary supplements like FOS contain a wealth of non-digestible carbohydrates that help maintain healthy gut flora.

FOS passes undigested into the colon in order to increase bowel mass and facilitate grow of certain good bacteria. FOS dietary supplements have been successful in treating traveler’s diarrhea, constipation, certain cancers, eczema, and high cholesterol levels. FOS can also relieve symptoms such as mild bloating and abdominal pain. Some studies have suggested that FOS dietary supplements can prevent the onset of food allergies.