Why some high-fibre diets cause gas - and what to do about it

If you want to reduce bloating when eating a high-fibre diet, try making it carbohydrate-rich rather than protein-rich, new study findings suggest.

Bloating is a common side effect that discourages many people from adopting a high-fibre diet.

For the study, researchers analysed data from a clinical trial involving 164 participants who followed heart-healthy, high-fibre diets. The participants were about 40% more likely to report bloating while following diets rich in plant proteins than on carbohydrate-rich regimens.

The findings were recently published online in the journal Clinical and Translational Gastroenterology.

High-fibre diets are believed to cause bloating by increasing certain populations of healthy, fibre-digesting gut bacteria. They produce gas as a byproduct. These findings suggest that carbs and proteins change the gut bacteria population (microbiome).

High-quality carbs

"It's possible that in this study, the protein-rich version of the diet caused more bloating because it caused more of a healthy shift in the composition of the microbiome," said study co-senior author Noel Mueller. He's an assistant professor of epidemiology at Johns Hopkins Bloomberg School of Public Health, in Baltimore.

"Notably, the protein in these diets was mostly from vegetable sources, such as beans, legumes and nuts," he added.

The findings suggest that substituting high-quality carbs - such as whole grains - for proteins might reduce bloating and make high-fibre diets more tolerable.

However, substituting proteins for carbohydrates might make such diets less healthy, the researchers noted in a Hopkins news release.

"Bloating may be just a consequence of a healthy shift in the microbiome, so that if somebody is able to put up with the bloating caused by a high-protein, high-fiber diet, they may ultimately benefit more in other health measures," Mueller said.

Image credit: iStock

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