Restricting Intake of Fermentable Carbohydrates May Reduce Symptoms of IBS

Researchers claim that restricting dietary intake of fermentable short-chain carbohydrates improves GI symptoms in patients with IBS.

Steve Parker, MD, recently wrote a post for the Paleo Diabetic blog that cited a study published in the Journal of Nutrition that claimed (according to Parker) that “four weeks of fermentable carbohydrate restriction reduces symptoms of irritable bowel syndrome.”

Parker wrote that he noticed “a major decrease in gastrointestinal gas production” when he cut his intake of digestible carbohydrates to less than 50g/day (done despite the fact that Parker does not have IBS). He wrote that this change in diet “has at least the potential to reduce IBS symptoms.”

He noted that the researchers “found changes in gut bacteria and a reduction in irritable bowel syndrome symptoms, as compared with control subjects. The particularly responsive symptoms were bloating, borborygmi, and the urge to defecate. Abdominal pain strongly tended to improve but didn’t quite reach statistical significance. Diarrhea wasn’t affected.” One caveat with the study is that “the IBS patients allowed into the study were not the type with constipation as a major issue,” according to Parker.

Limitations of the study identified by Parker include the fact that the researchers did not define “fermentable,” did not specify what foods were eaten by study subjects after they restricted fermentable carbohydrate consumption, and did define what was meant by their instructions to the participants in the intervention group that they “restrict” intake of specified foods.

Parker identified the FODMAP diet as possibly being the regimen followed during this study. The FODMAP diet (an acronym of “Fermentable, Oligo-, Di-, Mono-saccharides and Polyols”) is an elimination diet that can be used to identify GI-symptom-triggering foods for which there is no specific test.