Benefits of FOS

FOS is a naturally occurring complex carbohydrate found in small amounts in various plants. Along with other starchlike oligosaccharides such as inulin, FOS is mostly indigestible. FOS has been a popular supplement in Japan for years and is becoming increasingly respected in the West for its "prebiotic" effects. That is, it serves as an intestinal nutrient for the probiotic beneficial bacteria that naturally populate the gut. FOS thus promotes the ability of these bacteria to benefit overall health, especially their power to support proper digestion.

Benefits and uses Many people take FOS to prevent digestive ailments such as constipation and diarrhea. Among those who may particularly benefit from FOS's healthful effects on intestinal bacteria are people who have finished taking a course of antibiotics (antibiotics can seriously disrupt the balance of intestinal bacteria), people who eat a poor diet, visitors to foreign countries where "travelers' diarrhea" is a risk, and those who face constant stress. In addition to aiding digestion, FOS may also benefit diabetics by discouraging swings in blood sugar. By helping to eliminate or prevent the formation of toxic compounds, FOS may act to improve liver function. FOS supplements seem to benefit cardiovascular health by reducing blood fats and total cholesterol levels and lowering blood pressure. FOS's ability to increase resistance to infection may be especially helpful for people in long-term care facilities and hospital wards at increased risk of bacterial infections. FOS supports the production of various vitamins and minerals. Animal studies suggest that FOS may promote intestinal absorption of iron and calcium and thus help prevent anemia and loss of bone density.

Recent findings

A 1998 study done on pigs found that when FOS was added to an oral electrolyte solution as a treatment for acute diarrhea, it accelerated the recovery of beneficial bacteria while slowing the recovery of pathogenic forms. A review article noted that FOS has additional effects on digestive properties like stool bulking that justify its classification as a dietary fiber.

Do scientists know how it works?

The mechanism by which oligosaccharides like FOS promote intestinal health is well established. Numerous human studies done in Japan and elsewhere have shown that supplemental FOS is digested only to a small extent in the upper gastrointestinal tract. FOS passes virtually unchanged to the colon, where it is fermented and used as a fuel by beneficial bacteria, particularly bifidobacteria. FOS can help promote up to a ten-fold increase in the growth of bifidobacteria as well as other useful bacteria such as lactobacilli. Bacteria such as clostridium and E. coli (and other pathogenic organisms and their byproducts as well) that are harmful to human health, on the other hand, tend to be suppressed by the plentiful source of FOS.

Food sources

FOS occurs naturally in a variety of fruits, vegetables, and grains, especially bananas, onions, garlic, asparagus, barley, wheat, and tomatoes. The edible, potato-like tuber of a composite family plant, Jerusalem artichoke (Helianthus tuberosus), is a concentrated source of inulin. A tall, yellow-flowering relative of the sunflower, Jerusalem artichoke is a native North American plant that is not from Jerusalem and is not an artichoke (Cynara scolymus), although it is in the same plant family. A favorite remedy among those who follow the teachings of the late psychic Edgar Cayce, Jerusalem artichoke is also taken to help maintain a healthy colon.

Types of products

FOS is a mildly sweet, white, sugar-like powder; it also comes in capsules. It does not need to be refrigerated. Supplement manufacturers sometimes combine FOS with probiotic products such as acidophilus. FOS is also found in combination with garlic. FOS is a natural component of common foods and is considered safe and nontoxic. Very high dosages may cause intestinal gas in some people.

Books on FOS One is The Health Benefits of FOS (Fructooligosaccharides): "Fast Food" for the Friendly Bacteria That Keep Us Healthy by Robert Crayhon and Don Bensen (Keats, 1995).