Leptin and PAI-1 Levels Are Decreased After a Dietary Intervention in Patients with Irritable Bowel Syndrome.

A diet low in fermentable oligo-, di-, and monosaccharides and polyols (FODMAP) is an established treatment for irritable bowel syndrome (IBS). The starch- and sucrose-reduced diet (SSRD) is a newer, promising diet. Nutrients influence the production of gut hormones, which affect gastrointestinal motility. This study aimed to investigate the changes in copeptin, leptin, PAI-1, C-peptide, and insulin in patients with IBS following a 4-week dietary intervention and to explore whether these hormonal levels correlated with symptom improvements. A total of 142 participants with IBS were randomized to either a 4-week intervention with the SSRD (n = 70) or a low-FODMAP diet (n = 72). Participants completed the study questionnaire, food diary, ROME IV questionnaire, irritable bowel syndrome severity scoring system (IBS-SSS), and visual analog scale for irritable bowel syndrome (VAS-IBS) at baseline and after 4 weeks and 6 months; blood samples were collected at each of these time points. Leptin levels decreased from baseline to 4 weeks in the SSRD group ( = 0.002) but not in the low-FODMAP group ( = 0.153). In the overall study population, leptin ( = 0.001) and PAI-1 ( = 0.019) levels decreased from baseline to 4 weeks. Leptin changes were mainly associated with alterations in carbohydrate intake but not with symptom changes. These findings suggest that the SSRD reduces the levels of leptin in patients with IBS, while PAI-1 levels decrease independently of the dietary intervention, without a corresponding impact on symptoms.