ABSTRACT Background We previously found that the fecal levels of short‐chain fatty acids (SCFAs) changed in irritable bowel syndrome (IBS) patients at 1 month and 1 year after fecal microbiota transplantation (FMT). This study analyzed SCFAs at 2 and 3 years after FMT in the same IBS patients included in those previous studies. Methods This study randomized 113 IBS patients into placebo, 30‐g, and 60‐g groups, who received FMT with 30 g of their own feces and with 30 g and 60 g of the donor's feces, respectively. The patients completed four questionnaires to assess IBS symptoms, fatigue, and quality of life, and supplied fecal samples at the baseline and at 2 and 3 years after FMT. The fecal SCFA levels were measured using gas chromatography. Results The butyric acid level was significantly increased at 2 and 3 years after FMT in the 30‐g and 60‐g groups, and was significantly higher than that in the placebo group. The total SCFA and acetic acid levels decreased significantly in the 30‐g and 60‐g groups at 2 and 3 years after FMT, while the propionic acid level decreased in the 60‐g group at both time points. The butyric acid level was inversely correlated with IBS symptoms and fatigue. Conclusion and Inferences The increased butyric acid levels in IBS patients at 2 and 3 years after FMT and their inverse correlation with both IBS symptoms and fatigue suggest that butyric acid contributes to the long‐term improvement seen after FMT ( www.clinicaltrials.gov : NCT03822299).
El‐Salhy et al. (Fri,) studied this question.