The low-FODMAP diet for gut support
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Pete Williams (@petefmed) recently shared with me the following 2016 research study: It said: “the low Fermentable Oligo-, Di-, Monosaccharides And Polyols (low-FODMAP) diet has recently emerged as an effective intervention for reducing gastrointestinal symptoms in IBS.” The diet appears to be highly effective for dealing with IBS symptoms such as abdominal pain, bloating and diarrhoea. 

It’s a dietary approach that’s been around for a while, but what is it? According to the Stanford University Medical Centre, FODMAPs in the diet are:

  • Fructose (fruits, honey, high fructose corn syrup (HFCS), etc)
  • Lactose (dairy)
  • Fructans (wheat, garlic, onion, inulin etc)
  • Galactans (legumes such as beans, lentils, soybeans, etc)
  • Polyols (sweeteners containing isomalt, mannitol, sorbitol, xylitol, stone fruits such as avocado, apricots, cherries, nectarines, peaches, plums, etc)

Dietary FODMAPs may cause excess water to come into the intestinal tract, they might not be digested or absorbed well in certain people, and can be fermented by bacteria in the intestinal tract when eaten in excess.

According to the Stanford University Medical Centre, foods to avoid on a low-FODMAP diet include: high-lactose dairy, certain beans and nuts (such as cashews and lentils), gluten grains (wheat, barley, rye), chicory root, inulin, certain fruits (including apples, apricots, figs, plums and watermelon), certain vegetables (such as artichokes, cauliflowers and mushrooms), honey, high-fructose-corn-syrup (HFCS), and condiments and confectionary made with various types of refined sugars.   

The refined sugars in this list make a lot of sense to me - simply by cutting out MAN MADE  or MAN ALTERED refined sugars and carbs can reduce abdominal bloating and discomfort substantially. This is a basic requirement for good gut health. Additionally, some people don’t tolerate gluten grains and certain beans and nuts very well. So, for some people, this list of dietary exclusions will work very well where GI symptoms are concerned. 

In every clinical case, there is always a ‘but’ or a ‘what if’ in the argument for or against a certain strategy. This other 2016 paper supports the general effectiveness of the low-FODMAP diet in cases of IBS, but notes that it markedly reduces luminal Bifidobacteria concentration. Bifidobacteria is one of the main microbial species that us health professionals try to increase to facilitate improvements in gut health. 

So, taking this latest information into consideration, it leaves us with the question as to whether the low-FODMAP approach is best for gut health… or not. My own thought is that it is often appropriate to pick and choose your way though strategies for particular clients. As mentioned, the FODMAP principles may work beautifully for one client, whereas the Bifidobacteria levels may drop in another client, leading to worsening dysbiosis (imbalance of ‘good’ and ‘bad’ bacteria). The low-FODMAP list from Stanford University contains some really healthy foods including cauliflower, mushrooms, lentils, nuts and fruits. For some individuals, simply removing the refined foods from their diets may be enough and they can leave these good foods alone - whereas others genuinely do become bloated when they eat foods such as cauliflower and lentils. 

Exclusions to note from the low-FODMAP diet are the prebiotic fibre inulin and prebiotic fibre containing food, chicory root. Additionally, apple contains a lot of pectin, which is released when stewed - hence stewed apples are an old-fashioned way of improving gut health, due to the pectin they contain. As noted in this lovely little article, pectin is a prebiotic fibre and by eating apples daily, we can potentially increase Bifidobacteria and Lactobacillus species of bacteria. BUT, I find that raw apples make some people bloat, so I always prefer to advise the stewed form. 

So, just like every other subject in nutrition, it’s not cut and dry - try the low-FODMAP approach and it might yield some great results, or if you’re like me, pick and choose the dietary inclusions and exclusions based on what makes intuitive sense.