Consistent prebiotic effect on gut microbiota with altered FODMAP intake in patients with Crohn’s disease: a randomised, controlled cross-over trial of well-defined diets

Low FODMAP diet – not a ‘lifetime’ diet_e37efa8b

Monash FODMAP Team, 29 April 2016

Research by our team has recently identified that a reduction in FODMAP intake in individuals with Crohn’s disease who were in remission produced significant changes in the gut bacteria, particularly selected species with beneficial roles in gut health.

The effectiveness of a low FODMAP diet therapy in inflammatory bowel disease (IBD) had only been explored in a group of patients with IBS-like symptoms and inactive IBD. Considerable improvement in symptoms occurred in > 50% patients after 6 weeks of the diet. However, it is not known whether a low FODMAP diet there may be potential negative changes as seen in a recent study in IBS. An ‘imbalance’ in gut bacteria may already be occurring in some individuals with inflammatory bowel disease.

We recently studied the habitual FODMAP intake and gut bacteria of 8 participants with stable Crohn’s disease and the effects of altering their diets. They were fed diets containing either low FODMAP or a ‘typical Australian’ diet (see sample meal plan) for 3 weeks, followed by a 3-week break before crossing over to the other diet. Daily gut symptoms were measured as well as changes in stool bacteria during both dietary periods.

Sample meal plan Typical Australian diet Low FODMAP diet
Breakfast Honey quick oats or wheat flakes with dried fruit cereal
with ½ cup lactose-free milk
Packaged peaches
Brown sugar and cinnamon quick oats or rice bubbles
with ½ cup lactose-free milk
2 kiwi fruit
Morning tea Lactose-free yoghurt
2 rye vita crackers with cheese
Lactose-free yoghurt
2 rice cakes with cheese
Lunch Wheat sandwich
Vegetable fritata
Apple juice
Spelt sandwich
Low FODMAP vegetable frittata
Afternoon tea Pear
2 chocolate biscuits
2 gluten-free chocolate biscuits
Dinner Braised lamb shanks with vegetables
Salmon and vegetable couscous
Braised lamb shanks with low FODMAP vegetables
Salmon with low FODMAP vegetables and quinoa
Supper Apple sorbet Raspberry sorbet

Study findings:

  • When on a typical Australian diet, there was a significant increase in beneficial bacteria associated with favourable health outcomes compared to a low FODMAP diet, consistent with a ‘prebiotic’ effect.
  • However, overall symptoms, abdominal pain, bloating and excess flatulence were almost doubled than symptoms on a low FODMAP diet.
  • Interestingly, the habitual FODMAP intake in participants with Crohn’s disease was low, similar to levels on a low FODMAP diet. Not surprisingly, the low FODMAP diet did not improve the severity of gut symptoms compared to symptoms on their habitual diet.  

Take home messages:

  • A high FODMAP diet may produce beneficial prebiotic effects for gut health in Crohn’s disease. It suggests that trialling this diet during periods of active inflammation may not necessarily be ideal for the large bowel.
  • On the contrary, a low FODMAP diet may be beneficial in reducing residual IBS-like symptoms in individuals with inactive Crohn’s disease.
  • A specialist gastrointestinal dietitian will be able to advise on finding a balance between consuming adequate prebiotic FODMAPs and maintaining good symptom control.

Read the full article here.

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