New research from King's College London has found that a diet low in fermented carbohydrates has improved certain gut symptoms and improved health-related quality of life for sufferers of inflammatory bowel disease (IBD).

In a paper published today in Gastroenterology a team of researchers carried out a trial of a diet low in fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) in patients with IBD, experiencing persistent gut symptoms despite gut inflammation being under control. They found that a four-week low FODMAP diet improved certain gut symptoms such as swelling of the stomach and flatulence compared to those on a placebo diet.

Working with leading gastroenterologists from Bart's Health NHS Trust and Guys and St Thomas' NHS Foundation Trust, the researchers studied 52 patients who suffer from IBD, and who had persistent gut symptoms despite no on-going gut inflammation, and allocated them to two groups; one to a low FODMAP diet, restricting intakes of foods such as wheat, dairy, onions and garlic, and the other a controlled 'normal' FODMAP diet. Of the group that received the low FODMAP diet 52% reported adequate relief of gut symptoms, had a greater reduction in gut symptom severity and had a higher health-related quality of life score.

Lead researcher Dr Selina Cox from King's College London, said: "While we know that the low FODMAP diet is effective in patients with irritable bowel syndrome (IBS), this is the first randomised, trial showing that it's effective in reducing common gut symptoms. This improves health-related quality of life in patients with IBD when they are in remission."

Inflammatory bowel diseases include Crohn's disease and ulcerative colitis, both of which involve chronic inflammation of the digestive tract. At present, there is no cure for IBD, but symptoms are managed with a combination of anti-inflammatory and immune-modulating medication, and surgery. However, symptoms can persist during periods of disease remission even when they are receiving medication to control gut inflammation, and patients report these symptoms to have a large impact on their life.

The authors also found the low FODMAP diet reduces certain gut bacteria, such as Bifidobacteria, that may be beneficial to health and may reduce inflammation. Despite the changes in beneficial bacteria, gut inflammation did not appear to increase after the low FODMAP diet in patients with IBD.

"We carried out this randomised controlled trial to establish whether these common gut symptoms in patients with IBD in remission could be managed by the low FODMAP diet. Indeed, this could represent a safe and cost-effective management option." said Professor Kevin Whelan from King's College London.

The team now plan to study the effects of a longer-term low FODMAP diet and establish the effect of FODMAP reintroduction on gut symptoms and gut bacteria.

"In clinical practice, the low FODMAP diet is followed by a phase of gradual FODMAP reintroduction -- it is important to establish what the effects of FODMAP reintroduction are on the gut and whether reintroduction reverses the bacterial changes that were observed during the low FODMAP diet," added Dr Selina Cox.