Table 3

Comparison of gluten-free and low-FODMAP diets in patients with IBS with apparent wheat intolerance

Gluten-free dietLow FODMAP diet
Putative pathogenic mechanisms targeted▸ Epithelial injury, alteration of intestinal permeability
▸ Stimulation of innate immune mechanisms
Mechanoreceptor stimulation via luminal distension in small and large intestine
Likelihood of efficacy24% of 920 patients with IBS36Efficacy in 68–76%22
Time for responseNot reportedWithin 7 days65
Predictors of response▸ Increase intraepithelial density in duodenum53
▸ Positive double-blind placebo-controlled re-challenge or confocal laser endomicrosopic lesions in response to exposure 17
▸ Latent coeliac disease
Nil reported
Durability of responseDurable over 1 year (n=13) 1772% (n=90) satisfied with mean follow-up 15.7 months72
Ease of introduction▸ Large amount of high-quality literature available on the GFD
▸ Dietitians trained in GFD widely in some but not other countries
▸ No information regarding patients’ perspective
▸ High quality information readily available
▸ Paucity of dietitians trained in this diet in many countries
▸ 61% patients find it easy to follow, 44% easily incorporated into lifestyle in prospective study (n=90)72
AdherenceNot reported in this patient groupAdherence 76% in prospective (n=90) observational study72
Advantages▸ Diet directed to underlying pathogenic mechanism
▸ Widely understood and packaged/processed foods available in many countries
▸ Restriction only in one food group
▸ High chance of response
▸ In the long term, need only reduce the level of FODMAP intake sufficiently to achieve symptomatic benefit. Alternatives available across all four food groups
Disadvantages▸ Low chance of symptomatic response
▸ Gluten-free packaged/processed food:
– More expensive
– Often high fat, high sugar
– Issues of food texture (breads, pasta, cakes, biscuits)
▸ Exclusion diet=requirement for total abstinence from gluten
▸ Difficult in countries where food labelling inadequate
▸ Symptomatic therapy only
▸ Restrictions across a four food groups
▸ International food database of FODMAP content limited
▸ Limited availability of branded low FODMAP packaged and/or processed foods
Specific risks: nutritional adequacy▸ Restrictions on the intake of many breads and cereals may lead to deficient intake of folate, thiamine, fibre
▸ Calcium, iron and zinc intake less than population
▸ Many gluten-free foods not nutritionally balanced
▸ If not exchanged for low FODMAP alternatives:
– Restriction of lactose-containing dairy products may lead to deficient intake of calcium, vitamin D
– Restriction of legumes, grains and cereals may lead to deficient intake of folate, thiamine, fibre
▸ Natural prebiotic intake reduced65
Specific risks: other▸ Risks of precipitating an eating disorder
▸ Impaired ability to exclude coeliac disease if diet commenced prior to investigation
▸ Risks of precipitating an eating disorder
▸ Alteration of gut microbiota when on strict FODMAP restriction67 has unknown implications for long term
  • FODMAP, fermentable oligo-di-monosaccharides and polyols; GFD, gluten-free diet.