On a high fibre diet? More protein may increase bloating

January 29, 2020 in Healthy Eating, Nutrition Topics in the News

On a high fibre diet? More protein may increase bloating

People who eat high fibre diets are more likely to experience bloating if their diet is also protein-rich as compared to carbohydrate-rich, finds a new study led from Johns Hopkins Bloomberg School of Public Health.

Bloating is such a common side effect of a high fibre diet that it deters many people from adopting such diets. The new findings suggess that people who want to eat a high fibre diet would be less likely to experience bloating if the diet were relatively carb-rich (whole grains) versus plant protein-rich.

About the study

They were assigned to three different diets over consecutive six-week periods separated by two-week "washout" intervals during which participants returned to regular eating habits.

The diets were all considered high-fibre, low-sodium DASH diets. They all had the same number of calories but differed in their macronutrient composition.

The carbohydrate-rich version was, by calories, 58 percent carbohydrate, 15 percent protein, and 27 percent fat. The plant-protein-rich version was 48 percent carbs, 25 percent protein and 27 percent fat.

A key finding was that the prevalence of bloating went from 18 percent before the diets to 24, 33, and 30 percent, respectively, on the carb-, protein-, and fat-rich diets--indicating that these high fibre diets did indeed appear to increase bloating.

The plant protein-rich diet was tied to a 40 per cent greater chance of bloating in comparison with the carb-rich diet.

Bloating and gut bacteria link

High-fibre diets are believed to cause bloating by boosting certain populations of healthful fibre-digesting gut bacteria, which produce gas as a by-product. The findings hint that adjusting "macronutrients" such as carbs and proteins in one’s diet an modify the community of bacteria in the gut.

"It's possible that the protein-rich version of the diet caused more bloating because it caused more of a healthy shift in the composition of the microbiome. The protein was mostly from plant foods such as beans, legumes and nuts.

The takeaway

The results suggest that substituting high quality carb calories, such as whole grains, for protein calories might reduce bloating for those on high fibre diets, making such diets more tolerable.

There is the possibility, however, that making high fiber diets more tolerable in this way could also make them less healthy.

The plant- protein- and fat-rich diets in the study, which led to higher bloating prevalence, was previously found to lower blood pressure and improve blood cholesterol measures more than the carb-rich diet.

  Source: Clinical and Translational Gastroenterology, January 15, 2020.

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