January 6th, 2016

There is growing interest in the low FODMAP diet for those with digestive issues such as irritable bowel syndrome (IBS) and symptoms such as bloating, flatulance, diarrhoea and constipation. FODMAPs stands for fermentable oligo-, di- and mono-saccharides and polyols. The low FODMAP diet recommends avoiding or eliminating these short chain carbohydrates because they are incompletely absorbed in the small intestine and later fermented by the gut bacteria in the large intestine. This results in symptoms of bloating and gas (1). In this newsletter we will look at the pros and cons of the low FODMAPs diet and what it entails. There is also an accompanying chart of low and high FODMAP foods.

Research into FODMAPs

A meta-analysis published in the European Journal of Nutrition collated the results of 22 research trials into the effects of a low FODMAPs diet on IBS symptoms. They found a significant decrease in IBS symptoms in patients following the low FODMAPs diet (2). They recommend further research looking at a greater number of patients and longer adherence to the diet.

FODMAPs vs Traditional IBS Diet

Research comparing the low FODMAPs diet to traditional dietary advice for IBS patients found both diets had equally beneficial results. The traditional IBS dietary recommendations included avoidance of large meals along with reduced intake of fat, insoluble fibre, caffeine and gas producing foods such as beans, cabbage and onions (3).

Possible Long Term Problems

A review of research into the low FODMAPs diet by Danish researchers found that although most studies reported that the diet had symptomatic effects methodological weaknesses meant that a placebo response could not be ruled out. They also found no studies examining the important reintroduction phase (4).

Another area for concern is that the low-FODMAPs diet is associated with marked changes in the gut microbiota, specifically a reduction in those micro-organisms with prebiotic properties. These changes could have implications for the long term health of the gastrointestinal system and further investigation is needed (5).

How Does the Low FODMAPs Diet Work?

FODMAPs are short chain carbohydrates that are osmotic, meaning they pull water into the intestines. They are also incompletely digested in the small intestine meaning they continue into the large intestine where they are fermented by the colonic bacteria. The combination of osmosis and fermentation results in bloating and flatulence. Avoiding foods high in FODMAPs and replacing them with foods low in FODMAPs is thought to reduce the distension of the intestines with water and gases caused by bacterial fermentation.
Foods high in fibre tend to be high in FODMAPs as fibre is an indigestible carbohydrate found in plant foods. As fibre is generally thought to be beneficial to the gut bacteria and bowel health it is important that the low FODMAP diet be used as a temporary healing diet rather than a diet for life. It may also be appropriate for some people but not for others so consult with your medical practitioner or Nutritional Therapist before embarking on the diet.

The Low FODMAP Diet

FODMAPs in the diet include:

  • Fructose – fruit, honey, high fructose corn syrup (HFCS)
  • Lactose – dairy products
  • Fructans – wheat, garlic, onions, leeks, inulin
  • Galactans – beans, lentils, soya
  • Polyols – apricots, cherries, nectarines, peaches, plums, and sweeteners such as mannitol, sorbitol, xylitol etc.

Low FODMAP Recipes

Aubergine, Celeriac, Sweet Potato and Tahini Bake

Serves 4

3 tbsp olive oil
2 aubergines, quartered and cut into ½ cm slices
1 celeriac, peeled and cut into chunks
4 medium sized sweet potatoes (about 600g), peeled and chopped into bite sized pieces
3 tbsp tahini paste
Juice of 1 lemon
2 tbsp parsley, chopped
Freshly ground black pepper and salt
3 tbsp pumpkin seeds
1 tbsp paprika

  • Heat the olive oil in a pan and add the sliced aubergines. Cook on a low heat, stirring occasionally
  • Steam the celeriac and sweet potatoes for 8 minutes then add them to the aubergines. Continue cooking until all the vegetables are just cooked.
  • Meanwhile combine the tahini with the lemon juice and parsley and enough water to create a pouring sauce.
  • Transfer the vegetables to a baking dish, season with salt and pepper and stir in the tahini sauce.
  • Sprinkle on the pumpkin seeds followed by the paprika.
  • Bake in the oven on gas mark 5/190C/375F for 30 minutes.

Courgette Tortilla

Serves 2

3 tsp olive oil or butter
2 courgettes, sliced
4 eggs, beaten
Salt and pepper
Freshly chopped parsley

  • Heat the olive oil or butter in a heavy bottomed frying pan and add the courgettes. Stir intermittently until the courgettes are soft
  • Season the beaten eggs with salt, pepper and parsley and add this mixture to the pan.
  • Cook until the egg is nearly cooked through.
  • Finish the cooking by placing the pan under a medium hot grill for a few minutes until the egg has just set.
  • Serve with a lettuce and tomato salad.

FODMAPs References

1 – Iacovou M, Tan V, Muir JG, Gibson PR. The Low FODMAP Diet and Its Application in East and Southeast Asia. J Neurograstroenterol Motil. 2015 Sep 2. [Epub ahead of print]

2 – Marsh A, Eslick EM, Eslick GD. Does a diet low in FODMAPs reduce symptoms associated with functional gastrointestinal disorders? A comprehensive systematic review and meta-analysis. Eur J Nutr. 2015 May 17. [Epub ahead of print]

3 – Bohn L, Storsrud S, Liljebo T, Collin L et al. Diet low in FODMAPs Reduces Symptoms of Irritable Bowel Syndrome as Well as Traditional Dietary Advice: A Randomized Controlled Trial. Gastroenterology. 2015 Aug 5. [Epub ahead of print]

4 – Krogsgaard LR, Lyngesen M, Bytzer P. Insufficient evidence of the effect of the low FODMAP diet on irritable bowel syndrome. Ugeskr Laeger. 2015 Apr 27;177(18)

5 – Khan MA, Nusrat S, Khan MI, Nawras A, Bielefeldt K. Low-FODMAP Diet for Irritable Bowel Syndrome: Is It Ready for Prime Time? Dig Dis Sci. 2015 May;60(5):1169-77

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