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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).
References
- Ohta, A., et al., "Dietary fructooligosaccharides
prevent postgastrectomy anemia and osteopenia in rats," J
Nutr (1998), 128(3):485-90
- Ohta, A., et al., "Dietary fructooligosaccharides
prevent osteopenia after gastrectomy in rats," J Nutr
(1998), 128(1):106-10
- Oli, M.W., et al., "Evaluation of fructooligosaccharide
supplementation of oral electrolyte solutions for treatment of
diarrhea: recovery of the intestinal bacteria," Dig Dis
Sci (1998), 43(1):138-47
- Roberfroid, M.B., "Health benefits of non-digestible
oligosaccharides," Adv Exp Med Biol (1997), 427:211-19
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