'Limited evidence' for diet that claims to battle bloating
It is the latest diet that claims to combat bloating and Irritable Bowel Syndrome (IBS) by cutting out certain carbs. But the benefits of the FODMAP food plan have been cast into doubt by researchers who found little evidence of these benefits.
FODMAP involves cutting out types of carbohydrates that are not easily broken down and absorbed by the small intestine. These include wheat, onions, legumes, honey, apples, and the artificial sweeteners used in confectionery - sorbitol and mannitol.
Its advocates claim it eases the discomfort caused by IBS, which is suffered by one-in-five people - including actress Kirsten Dunst and supermodel Tyra Banks.
However, the Drug and Therapeutics Bulletin has revealed that there is very little evidence for cutting out certain carbs to ease irritable bowel.
The low FODMAP diet, which was developed in Australia, is based on the observation that certain types of short-chain carbs are poorly absorbed by the small intestine. They are rapidly fermented in the gut, increasing water volume and gases, and it is claimed IBS symptoms worsen when these foodstuffs are eaten.
After assessing the available published evidence and guidelines on the management of IBS, the Drug and Therapeutics Bulletin says there is some evidence that patients feel the diet reduces some of the symptoms.
And one study indicates that the diet changes the profile of the bacteria in the gut, although what the clinical implications of this are, or, indeed, what the long-term effects might be, are unclear.
But data to back the use of a low FODMAP diet as an effective treatment to control symptoms "is based on a few relatively small, short-term unblinded or single-blinded controlled trials of varying duration," it cautions.
And dietary changes are not without drawbacks, as some people fail to maintain a balanced diet.
It says FODMAP might be appropriate for motivated people who have tried other treatments that have not eased their symptoms. But it should be done under the supervision of a dietitian with specialist expertise in this type of dietary intervention, it recommends.
And it concludes: "We believe that patients should be advised that there is very limited evidence for its use, the ideal duration of treatment has not been assessed in a clinical trial, and its place in the management of IBS has not been fully established."