J Clin Gastroenterol. 2021 Mar 12. doi: 10.1097/MCG.0000000000001521. Online ahead of print.

Gerardo Calderon ¹, Chirag Patel, Michael Camilleri, Toyia James-Stevenson, Matthew Bohm, Robert Siwiec, Nicholas Rogers, John Wo, Carolyn Lockett, Anita Gupta, Huiping Xu, Andrea Shin

Author information

• ¹*Division of Gastroenterology and Hepatology, Department of Medicine, Indiana University School of Medicine ‡Department of Biostatistics; Indiana University School of Medicine, Indianapolis, IN †Clinical Enteric Neuroscience Translational and Epidemiological Research (C.E.N.T.E.R.), Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN.

Abstract

Background & goals: Diet may contribute to symptoms of irritable bowel syndrome (IBS) and luminal production of putative IBS biomarkers including short-chain fatty acids (SCFAs). Study aims were to to assess relationships of habitual fiber or starch intake with fecal SCFAs in patients with IBS and healthy volunteers (HVs).

Study: In 18 HVs and 30 patients with IBS (13 constipation-predominant [IBS-C] and 17 diarrhea-predominant [IBS-D]), habitual diet using a food frequency questionnaire; bowel functions using a validated bowel diary; and fecal SCFAs by HPLC-mass spectrometry were assessed. Associations of fiber and starch with SCFAs were analyzed using Spearman (rs) and Pearson (R) correlations. Relationships between other dietary endpoints, SCFAs, and bowel functions were explored.

Results: Habitual fiber or starch intakes were not significantly correlated with SCFAs or bowel functions in all participants or HVs nor with SCFAs in IBS. Starch was negatively correlated (R=-0.53; P=0.04) with complete evacuation in IBS-D. Fiber (rs=0.65; P=0.02) and starch (rs=0.56; P=0.05) were correlated with ease of passage in IBS-C. Stool form, frequency, and ease of passage were positively correlated with total SCFAs (all P<0.05), acetate (all P<0.01), propionate (all P<0.05), and butyrate (form P=0.01; ease of passage P=0.05) among all participants, but not in IBS. Complete evacuation was negatively correlated with propionate (R=-0.34; P=0.04) in all participants. Total (P=0.04) and individual SCFAs (all P<0.05) were positively correlated with stool form in HVs.

Conclusions: Habitual fiber and starch intake does not influence fecal SCFAs but may influence bowel functions in IBS. Fecal SCFAs correlate with bowel functions among all participants including HVs.