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Oligosaccharides Definition

Oligosaccharides [Greek oligo = few; sacchar = sugar] are carbohydrates composed of 3 to 9 monosaccharides.


Picture 1. An oligosaccharide example: raffinose

Examples of Oligosaccharides in Foods

  • Arabinoxylan-oligosaccharides (derived from cereal grains)
  • Fructo-oligosaccharides (FOS) or oligofructose (Jerusalem artichokes, onions, canned foods)
  • Galacto-oligosaccharides (GOS): raffinose, stachyose and verbascose (in beans, peas, lentils, cabbage, whole grains), soybean oligosaccharides in soy, and trans-galactooligosaccharides (TOS),
  • Gentio-oligosaccharides (produced from pustulan)
  • Gluco-oligosaccharides (produced from sucrose)
  • Human milk oligosaccharides (HMO) (human breast milk)
  • Isomalto-oligosaccharides or IOS (produced from starch)
  • Lactosucrose (produced from lactose and sucrose)
  • Maltotriose (produced from starch during digestion, found in liquid glucose, brown rice syrup)
  • Mannan-oligosaccharides or MOS (artificially produced)
  • Melibiose-derived oligosaccharides
  • N-acetylchito-oligosaccharides (derived from chitosan)
  • Pectic oligosaccharides (derived from pectin)
  • Xylo-oligosaccharides (produced from corncob and birch wood)

Oligosaccharides are often added to commercial foods as sweeteners or fiber.

Digestion, Fermentation, Absorption, Function, Side Effects

Oligosaccharides, except maltotriose, are indigestible, which means humans lack enzymes to break them down in the small intestine, so they reach the large intestine, where beneficial colonic bacteria break them down (ferment) to absorbable nutrients, which provide some energy–about 2 Calories (kilocalories) per gram in average [1]. Certain breakdown products of oligosaccharides–namely short-chain fatty acids (SCFAs)–may have beneficial effect on large intestinal lining.

Most oligosaccharides act as a soluble fiber, which may help prevent constipation. Ingestion of large amount of oligosaccharides can result in abdominal bloating and excessive gas (flatulence).

Oligosaccharides as Prebiotics

Prebiotics are non-digestible nutrients that selectively promote the growth of normal intestinal bacteria that may have beneficial effects on the large intestinal lining. Oligosaccharides currently considered as prebiotics include fructooligosaccharides (FOS) or oligofructose and trans-galactooligosaccharides (TOS) [2].

Related Nutrients

9 Responses to "Oligosaccharides"

  1. Elaine Parduhn says:

    I really do not understand what the difference is between Saccharomyces and that with MOS.

    • Jan Modric says:

      Elaine, MOS refers to mannan-oligosaccharides, which are a type of oligosaccharides.

      Saccharomyces is a type of yeasts often found in probiotic supplements.

  2. George Dehnel says:

    The statement “…short chain fatty acids may have beneficial effect on large intestinal lining” needs to be seriously modified. The qualifier “may” is not only very misleading but incorrect. SCFAs are incredibly important for the function of the bowel as well as other parts of our body.

    • Jan Modric says:

      There is a separate article for short-chain fatty acids. One section there says:

      There is INSUFFICIENT EVIDENCE about the effectiveness of short-chain fatty acids (SCFA) in the prevention or treatment of colorectal cancer [2,8,9], ischemic stroke, treating obesity, high blood cholesterol, diabetes type 2, sickle cell disease, Crohn’s disease and ulcerative colitis [10,11,12,13], post-infectious irritable bowel syndrome (IBS) [7], increasing calorie delivery in cystic fibrosis [14], prevention ammonia or toxins absorption from the intestine, constipation, antibiotic-associated diarrhea.

      The role of SCFA produced by the intestinal bacteria in immunity is not clear yet: they may either promote or inhibit inflammation in the body [17,18,19].

      The numbers in brackets are references from that article. In summary, the authors of the studies agree that SCFAs nourish the beneficial intestinal bacteria and the intestinal lining, but it has not yet been clearly established if they can actively treat or prevent intestinal or immune disorders.

  3. Is saccharomyces found in probiotics?

    • Jan Modric says:

      Saccharomyces is found in some, but not all, probiotic products – you can usually read this on the product label.

  4. David Lee says:

    WebMD writes:


    “Auto-immune diseases” such as multiple sclerosis (MS), lupus (systemic lupus erythematosus, SLE), rheumatoid arthritis (RA), or other conditions: Galacto-oligosaccharides might cause the immune system to become more active. This might increase the symptoms of auto-immune diseases. If you have an auto-immune condition, it’s best to avoid using galacto-oligosaccharides as medicine until more is known.

    Is there a problem if you have had an autoimmune disease, if it is included in a Prebiotic product, as in Prebiothrive?

    • Jan Modric says:

      “It might” – it’s probably a theoretical warning, not something proven by studies.

      • Josie says:

        FINALLY, someone understands ‘may’ vs. ‘might’! You are ‘one in a million’, and I suspect that you already knew that!

        For those who don’t:
        ‘May’ = permission, e.g., May I use your pen?
        ‘Might’ = probability, e.g., It might snow tonight.

        Just sayin’…

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