The term “oligosaccharide” refers to a short chain of sugar molecules (“oligo” means “few” and “saccharide” means “sugar.”) Fructo-oligosaccharides (FOS) and inulin, which are found in many vegetables, consist of short chains of fructose molecules. Galacto-oligosaccharides (GOS), which also occur naturally, consist of short chains of galactose molecules. These compounds can be only partially digested by humans.1 2 3 4 When oligosaccharides are consumed, the undigested portion serves as food for “friendly” bacteria, such as Bifidobacteria and Lactobacillus species.
Where is it found?
FOS and inulin are found naturally in Jerusalem artichoke, burdock, chicory, leeks, onions, and asparagus. FOS products derived from chicory root contain significant quantities of inulin,5 a fiber widely distributed in fruits, vegetables and plants, which is classified as a food ingredient (not as an additive) and is considered to be safe to eat.6 In fact, inulin is a significant part of the daily diet of most of the world’s population.7 FOS can also be synthesized by enzymes of the fungus Apergillus niger acting on sucrose. GOS is naturally found in soybeans and can be synthesized from lactose (milk sugar). FOS, GOS, and inulin are available as nutritional supplements in capsules, tablets, and as a powder.
FOS, GOS, and inulin have been used in connection with the following conditions (refer to the individual health concern for complete information):
| Science Rating | Health Concerns |
|---|---|
 | Elevated triglyceride levels |
 | Pre- and post-surgery health Type 2 diabetes |
 Reliable and relatively consistent scientific data showing a substantial health benefit. Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit. For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support and/or minimal health benefit. | |
Who is likely to be deficient?
As FOS, GOS, and inulin are not essential nutrients, no deficiency state exists.
How much is usually taken?
The average daily intake of oligosaccharides by people in the United States is estimated to be about 800 to 1,000 mg. For the promotion of healthy bacterial flora, the usual recommendation for FOS, GOS, or inulin is 2,000 to 3,000 mg per day with meals. In the studies on diabetes and high blood lipids (cholesterol and triglycerides), amounts ranged from 8 to 20 grams per day.
Are there any side effects or interactions?
Generally, oligosaccharides are well tolerated. Some people reported increased flatulence in some of the studies. At higher levels of intake, that is, in excess of 40 grams per day, FOS and the other oligosaccharides may induce diarrhea.
There is a report of a 39-year old man having a life-threatening allergic reaction after consuming high amounts of inulin from multiple sources, including FOS.8 Allergy to inulin in this person was confirmed by laboratory tests. Such sensitivities are extremely rare. People with a confirmed sensitivity to inulin should probably avoid FOS.
References
1. Molis C, Flourie B, Ouarne F, et al. Digestion, excretion, and energy value of fructooligosaccharides in healthy humans. Am J Clin Nutr 1996;64:324-8.
2. van Dokkum W, Wezendonk B, Srikumar TS, van den Heuvel EG. Effect of nondigestible oligosaccharides on large-bowel functions, blood lipid concentrations and glucose absorption in young healthy male subjects. Eur J Clin Nutr 1999;53:1-7.
3. Alles MS, Hautvast JGA, Nagengast FM, et al. Fate of fructo-oligosaccharides in the human intestine. Br J Nutr 1996;76:211-21.
4. Roberfroid M. Dietary fibre, inulin and oligofructose. A review comparing their physiological effects. Crit Rev Food Sci Nutr 1993;33:103-48 [review].
5. Duke JA. Handbook of phytochemical constituents of GRAS herbs and other economic plants. Boca Raton, FL: CRC Press, 1992.
6. Carabin IG, Flamm WG. Evaluation of safety of inulin and oligofructose as dietary fiber. Regul Toxicol Pharmacol 1999;30:268–82 [review].
7. Coussement PA. Inulin and oligofructose: safe intakes and legal status. J Nutr 1999;129:1412S-7S [review].
8. Gay-Crosier F, Schreiber G, Hauser C. Anaphylaxis from inulin in vegetables and processed food. N Engl J Med 2000;342:1372 [letter].
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2006-09-07
