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XOS vs FOS vs GOS

Discussion in 'The Gut: De Meirleir & Maes; H2S; Leaky Gut' started by ebethc, Apr 4, 2018.

  1. ebethc

    ebethc Senior Member

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    1) does anyone know the difference between XOS, FOS and GOS? specifically, which do you take to increase which gut bacteria

    • XOS - PreticX (Xylooligosaccharides) has been shown in clinical studies to promote the growth of Bifidobacterium.
    • GOS - (Galactooligosaccharides) are the principal type of prebiotics found in human milk. RELATED TO WHICH GUT BACTERIA?
    • FOS - RELATED TO WHICH GUT BACTERIA?
    2) Does anyone know which prebiotics map to which of these? for example, I'm currently taking aribinogalactan, so which of those do the galactans map to (GOS or FOS)?
     
  2. Carl

    Carl Senior Member

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    Inulin is another which is similar to FOS but has slightly longer molecules.
    Fermentation of Fructooligosaccharides and Inulin by Bifidobacteria: a Comparative Study of Pure and Fecal Cultures
    This site says that FOS can have some negative effects due to the micro-organisms which can metabolise it such as Candida and other unwanted micro-organisms

    Another one to consider is natural food resistant starch which does contain small amounts of the items already mentioned which are also helpful to the colonic bacteria. Green Bananas can be helpful which are not too difficult to get.
    I found this on GOS but have not read it fully yet, it looks like it might be relevant and/or provide further research sources to check.
     
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  3. ebethc

    ebethc Senior Member

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    Thanks! I haven't tried resistant starch... It seems like something that I shouldn't be eating b/c it's too carby (starchy?)
     
  4. lafarfelue

    lafarfelue Senior Member

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    Just poking around the internet, I've found a few pieces that seem to say similar things about GOS. I've included the relevant sections below, along with links.

    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2607002/#!po=56.9444
    Galacto-oligosaccharides and bowel function
    [...]GOS may alter bowel function through a change in the colonic environment. In vitro studies have shown that the bacterial fermentation of oligosaccharides increases the production of short-chain fatty acids (SCFAs) 11, 29, which lowers colonic pH 28. The lower colonic pH may stimulate the growth of lactobacilli and bifidobacteria and suppress the growth of undesirable bacteria 29. [...]
    https://www.ncbi.nlm.nih.gov/m/pubmed/16214761/
    Galacto-oligosaccharides and long-chain fructo-oligosaccharides as prebiotics in infant formulas: a review.
    [...]The results from several studies, made up of over 400 preterm and term infants, clearly demonstrate that the prebiotic mixture under examination specifically stimulates the growth of bifidobacteria and lactobacilli and reduces the growth of pathogens. As a consequence of the changed intestinal flora by the dietary galacto-oligosaccharides and fructo-oligosaccharides, the faecal pH values and the short-chain fatty acid pattern were similar to those found in breastfed infants. In addition, the stool consistency was the same as in breastfed infants. In vitro experiments have demonstrated that the specific short-chain fatty acid pattern, at a pH similar to that found in faecal samples of breastfed infants, reduces the growth of pathogens in a dose-dependent manner but does not influence the growth of bifidobacteria and lactobacilli.[...]​

    https://en.m.wikipedia.org/wiki/Galactooligosaccharide
    [...]
    Stimulating bacteria

    Galacto-oligosaccharides are a substrate for bacteria, such as bifidobacteria and lactobacilli. Studies with infants and adults have shown that foods or drinks enriched with galacto-oligosaccharides result in a significant increase in bifidobacteria.[1]

    Immune response
    Human gut microbiota play a key role in the intestinal immune system.[1] Galacto-oligosaccharides support natural defenses of the human body via the gut microflora,[5]indirectly by increasing the number of bacteria in the gut and inhibiting the binding or survival of Escherichia coli, Salmonella Typhimurium and Clostridia.[6][7] GOS can positively influence the immune system indirectly through the production of antimicrobial substances, reducing the proliferation of pathogenic bacteria.[8][9]
    [...]​
     
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  5. lafarfelue

    lafarfelue Senior Member

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    Couldn't find much on FOS, but I'm getting pretty brainfoggy. Earlier, I thought I saw something saying that FOS wasn't digestible/used by the lower colon or something, but I haven't been able to find that particular page/passage again.

    https://en.m.wikipedia.org/wiki/Fructooligosaccharide
    [...]
    Health benefits
    FOS serves as a substrate for microflora in the large intestine, increasing the overall gastrointestinal tract (GI Tract) health. It has also been proposed as a supplement for treating yeast infections.[8]

    Several studies have found that FOS and inulin promote calcium absorption in both the animal and the human gut.[9][10] The intestinal microflora in the lower gut can ferment FOS, which results in a reduced pH. Calcium is more soluble in acid, and, therefore, more of it comes out of food and is available to move from the gut into the bloodstream.

    FOS can be considered a small dietary fibre with (like all types of fibre) low caloric value. The fermentation of FOS results in the production of gases and acids. The latter provide some energy to the body.

    Side-effects
    All inulin-type prebiotics, including FOS, are generally thought to stimulate the growth of Bifidobacteria species. Bifidobacteria are considered beneficial bacteria. This effect has not been uniformly found in all studies, either for Bifidobacteria or for other gut organisms.[11][unreliable source?] FOS are also fermented by numerous bacterial species in the intestine, including Klebsiella, E. coli[12] and many Clostridium species, which can be pathogenic in the gut. These species are responsible mainly for the gas formation (hydrogen and carbon dioxide), which results after ingestion of FOS. Studies have shown that up to 20 grams/day is well tolerated.[13]
     
  6. vaer

    vaer

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    Last edited: Apr 4, 2018
  7. alicec

    alicec Senior Member

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    FOS, XOS and GOS are short, linear chains of the sugars fructose, xylose and galactose respectively. The relatively small size means they are classified as oligomers, rather than larger polymers and the presence of sugar molecules makes them oligosaccharides.

    The chemical linkage between the sugar molecules is one that humans can't digest so the molecules pass into the colon unaltered. Many gut bacteria can digest the linkage and use the sugar molecules for energy.

    All three substances are laboratory creations though they are related to naturally occurring substances.

    As already noted, FOS is similar to inulin. It is produced by enzymatic treatment of inulin to produce shorter chain lengths. Generally, oligomers with greater than about 10 fructose residues are considered to be inulins, less than 10, FOS. The longest inulins contain about 60 residues.

    XOS is an extremely simplified version of xylans in plant cell walls, likewise GOS is a poor approximation of human milk oligosaccharides (HMOs).

    These laboratory creations are easier to handle and sell as supplements - readily soluble, easy to produce etc. In general they appear to be readily fermented by a wide variety of bacteria.

    You would need to do specific research if you were interested in promoting growth of particular bacteria in your gut.

    The arabinogalactan you mention consists of a basic chain of galactose molecules with side chains of arabinose. So it is most like GOS though more complex.

    Starch, like inulin, is used by plants for energy storage. It is a very large polymer of glucose, often with a complex branched structure. Unlike inulin, we can digest some of the starch, but some we can't. This is resistant starch, which our gut bacteria can ferment and which is an important prebiotic food.

    Resistant starch is usually classified into four types. RS1 is trapped in plant cell walls which we can't digest and so becomes available to gut microbes. There is a lot of this in food like beans.

    RS2 is found in green bananas, plaintains and raw potatoes. It can be found in pure form in raw potato starch which we don't digest at all - it is not "starchy". If cooked though it does become digestible.

    RS3 is retrograde starch, formed when cooked starch cools. So hot, cooked potatoes are largely digested by us but cooled into potato salad and a significant proportion of this starch becomes undigestible and can feed our gut bacteria.

    RS4 is a laboratory creation akin to FOS, GOS and XOS. It is often called dextrin, usually derived from wheat.

    Personally I think that all these laboratory creations should be used with caution. Small amounts are probably fine but if you want to boost prebiotic intake with concentrated preparations (as opposed to relying only on vegetable intake) then a variety of less processed options such as raw potato starch, larch extract (your arabinogalactans), pectins, acacia and guar gums, baobab extract, aloe vera - to name just a few off the top of my head - are more like what our gut bacteria have evolved to eat.
     
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