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According to the following citation and now many subsequent papers, FODMAPs containing foodstuffs are a viable treatment option for a variety of prolems originating in your gut:

Personal view: food for thought–western lifestyle and susceptibility to Crohn's disease. The FODMAP hypothesis:
The association of Crohn's disease with westernization has implicated lifestyle factors in pathogenesis. While diet is a likely candidate, evidence for specific changes in dietary habits and/or intake has been lacking. A new hypothesis is proposed, by which excessive delivery of highly fermentable but poorly absorbed short-chain carbohydrates and polyols (designated FODMAPs--Fermentable Oligo-, Di- and Mono-saccharides And Polyols) to the distal small intestinal and colonic lumen is a dietary factor underlying susceptibility to Crohn's disease. The subsequent rapid fermentation of FODMAPs in the distal small and proximal large intestine induces conditions in the bowel that lead to increased intestinal permeability, a predisposing factor to the development of Crohn's disease. Evidence supporting this hypothesis includes the increasing intake of FODMAPs in western societies, the association of increased intake of sugars in the development of Crohn's disease, and the previously documented effects of the ingestion of excessive FODMAPs on the bowel. This hypothesis provides potential for the design of preventive strategies and raises concern about current enthusiasm for putative health-promoting effects of FODMAPs. One of the greatest challenges in defining the pathogenesis of Crohn's disease is to identify predisposing environmental factors. Such an achievement might lead to the development of preventive strategies for, and the definition of, possible target for changing the natural history of this serious disease.

While the evidence is mounting that this a indeed an interesting treatment option, it looks like an either very counter-intuitive or even contrafactual or contradictory logic to other received wisdom about nutrition. A healthy gut is populated with a very diverse microbiome and that microbiome is fostered on a diet rich in fibre and probiotics, prebiotics, including the FODMAPs.

Given that FODMAP-lists frequently do not contain not only a list of ready made convenience products, industrially enriched with said substances, but a long list of natural foods containing various amounts of the FODMAPs, it conflicts with the advice to supposedly generally improve a typical western diet with more fibre and prebiotics.

Example: Wheat/rye breads, couscous, wheat pasta, barley and gnocchi Jerusalem artichokes, garlic, onion, leek, asparagus, beetroot, peas, snow peas, and sweet corn. Nectarines, peaches, watermelon, persimmons, rambutan, grapefruit, pomegranate, dried fruit, custard apples. Cashews and pistachios; Foods containing inulin

While it is obviously not very advisable at all to follow these restrictions if you are healthy just because gluten-free is so last year and you are in dire need for a new fad, I still wonder if the whole concept is indeed viable, despite the evidence. Even in strictly prescribed diets it is simply not feasible to apply all these restrictions long term and not even called for.

Finding papers criticising 'low-FODMAP’ is not hard, but I struggle to find the theoretical concept behind the actual positive evidence criticised in a paper that is also providing alternatives in comparable evidence level of never reducing prebiotic FODMAPs (in populations that seem to be in the benefitting target audience).

In short: Is the FODMAP hypothesis providing red-herring quality evidence or how do we reconcile the two positions of increasing prebiotic intake with lowering FODMAP intake.

5
+50

The question, as I understand it: Should the current recommendations about a low-FODMAP diet, which is also low-prebiotic and thus potentially harmful, be changed?

Short answer: There is some evidence that a low-FODMAP diet can reduce symptoms in individuals with fructose malabsorption and irritable bowel syndrome but no clear evidence about its harms. So, I don't think the diet should be changed, but some aspects could be reconsidered:

  • A low-FODMAP diet needs to be only as strict as necessary to prevent symptoms.
  • Individuals with IBS should try to treat their problems by solving their psychological issues and not only by a low-FODMAP diet.

(FODMAPs - Fermentable Oligo-, Di- and Monosaccharides and Polyols include: nondigestible oligosaccharides, lactose, fructose and sugar alcohols - sorbitol, xylitol, etc. From this list, only certain oligosaccharides are considered prebiotics (article, or directly, table 4). Prebiotics are nutrients that promote the growth of beneficial intestinal microbes.)


In certain gastrointestinal conditions, mainly fructose malabsorption, FODMAPs are poorly absorbed in the small intestine, so they reach the large intestine, where they feed normal intestinal bacteria, which produce excessive gas, and also cause osmotic diarrhea. The aim of a low-FODMAP diet is to reduce the feeding of the intestinal bacteria and thus reduce the symptoms.


EVIDENCE:

1. A low-FODMAP diet can reduce symptoms in fructose malabsorption and IBS.

Most study reviews, including the ones from 2016-2017 linked here, provide some evidence that a low-FODMAP diet decreases symptoms in individuals with fructose malabsorption (1, 2) and diarrhea-predominant irritable bowel syndrome (3, 4, 5, 6).

2. A low-FODMAP diet can reduce symptoms in Crohn's disease, but does not likely prevent the disease itself.

A low-FODMAP diet can be used as a temporary measure to reduce symptoms in Crohn's disease (PMC). On the other hand, there is no convincing evidence that this diet decreases the risk of developing Crohn's disease.

3. Is a low-FODMAP diet potentially harmful?

This and this review from 2017 raise concern that a low-FODMAP diet may lead to nutrient deficiency and suboptimal intestinal flora and that...more research is needed.

CONCLUSIONS:

  1. Even if there is a lot of evidence that high-fiber diet, which is often also high-prebiotic, can be beneficial for health (PubMed), there seems to be no clear evidence that a low-FODMAP diet, which is also low-prebiotic, is harmful.
  2. Every therapeutic approach, including a low-FODMAP diet, is justifiable until the health benefits outweigh the possible harms. For example, in fructose malabsorption, a commonly documented significant reduction in symptoms seems to outweigh theoretically possible but non-documented harms.
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  • So far… My main complaint in the Q should revolve not around "for healthy people" (fad) but whether low-fibre and esp type oligo-x might be a less than ideal over-stretch of the hypothesis, since: gut microbiome is thought to profit in general (or why not in GIT?) from oligo-x (+ fermentables?). In short I'd like to know a bit more about the assumed or observed similarities of conditions and from there a bit more from the causative explanation side. – Does this comment. – After reading this comment: Is that clear enough from the Q or should I edit? (No moving goal: after bounty? ) – LаngLаngС Jun 6 '18 at 15:07
  • HiHi. Science and hype are often not in conflict but the source of it – The possible conflict I'd like resolved is only about the position of scientifically grounded advice 1(eat fibre, foster microbiome) and 2(in case of GIT, maybe do the opposite, try lowFODMAP). If 1 is generally true, why is 2 counterintuitively the opposite (from a certain view)? Basic assumption is: gut health is important for healthy, general population, and malabsorbers. Since things like stool transplants are tried in that area as well, why and how is "starving the mcirobiome" in those cases for FODMAP a +idea? – LаngLаngС Jun 6 '18 at 15:23
  • That's correct. But what then really causes the gas? The fermentation. Who is fermenting? Not those cells with human DNA. There I see the possibility that the original idea might be incomplete – or my hypothesis laden with flawed reasoning or incomplete data: I suspect a viable path might exist that's quicker than the currently advised regime to a healthier gut and tolerance of FODMAPs. Put simply: everyone needs "healthy" microbiota, especially malabsorbers? – LаngLаngС Jun 6 '18 at 15:36
  • And if that is ref'ed & explained with a refutation of the hypo/idea that e.g. "oligo-x" helps the beneficial bacteria and (therefor general gut health, even for the patients, which should be a goal for them too [further hypo: one reason for the mentioned diseases is overly "unhealthy microbiome", cause for that exactly unkown]), maybe the diff for that between general population and patients, I think we've zeroed it in much better. Please feel free to also edit the Q by yourself if you think that will be clearer then (after reading this exchange I suspect to have misled you a bit) or chat? – LаngLаngС Jun 6 '18 at 15:50
  • Chat is just an option to avoid lengthy comment threads that should be nuked otherwise… // but while I certainly disagree about the limited interpretation that narrows it down to SFCAs (& eventually unknnwn qualities of those): everything (incl SFCAs) in this comment thread I see of great value if added to the answer. – LаngLаngС Jun 6 '18 at 16:06

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