In people with irritable bowel syndrome, low FODMAP diets improve symptoms compared with other dietary guidance

Black CJ, Staudacher HM, Ford AC Efficacy of a low FODMAP diet in irritable bowel syndrome: systematic review and network meta-analysis. Gut. 2022;71:1117-26.

Review question

In people with irritable bowel syndrome (IBS), what is the effect of a diet low on fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) on IBS symptoms compared with other dietary advice, sham, or habitual or usual diet?

Background

IBS is a common condition that affects the large intestine but doesn’t cause any damage to it. There is no test to diagnose IBS, and its cause is unknown. People with IBS often experience symptoms like constipation, diarrhea, stomach pain or cramps, bloating, and gas. These symptoms may be managed with medications, probiotics, stress management techniques, or diet changes.

Low FODMAP diets omit foods that are poorly absorbed in the bowel. Some of these foods include garlic, onions, and many types of beans (a full list is easily found on the Internet). Other dietary advice from the British Dietetic Association (BDA) and the UK National Institute for Health and Care Excellence (NICE) suggests eating small, regular meals; staying hydrated; drinking less tea, coffee, alcohol, and carbonated drinks; and limiting the amount of fruit eaten. This review looks at how well a low FODMAP improves IBS symptoms.

How the review was done

The researchers did a systematic review of studies available up to April 2021. They found 13 randomized controlled trials that included 944 people.

The key features of the studies were:

• people were at least 18 years of age and were diagnosed with IBS;
• studies compared low FODMAP diets with BDA/NICE dietary advice, sham dietary advice, habitual diet, alternative dietary advice, or a high FODMAP diet; and
• people followed the diet for 3 weeks to 3 months.

What the researchers found

• Low FODMAP diets improved IBS symptoms in more people compared with all other diets.

The quality of the evidence was low, which means that new studies might show different results.

Conclusion

In people with IBS, there is low-quality evidence that low FODMAP diets improve symptoms more than other dietary advice.

Low FODMAP diet vs. other diets for irritable bowel syndrome (IBS)

BDA = British Dietetic Association. FODMAP = fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. NICE = National Institute for Health and Care Excellence.

*Advises eating small, regular meals; staying hydrated; drinking less tea, coffee, alcohol, and carbonated drinks; and limiting the amount of fruit eaten.