BACKGROUND: Bariatric surgery (BS), including Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG), effectively treats severe obesity through enhanced secretion of satiety hormones (glucagon-like peptide-1 [GLP-1], peptide-YY [PYY]). However, these hormonal elevations cannot be sustained long-term, resulting in diminished efficacy. Postoperative dietary fiber (DF) intake is critically low post-BS, yet DF may enhance short-chain fatty acid (SCFA)-producing microbiota and stimulate the secretion of GLP-1 and PYY, potentially sustaining metabolic benefits.
OBJECTIVES: The trial aimed to investigate the effect of DF supplementation (oat bran) on gut microbiota, hormones, and glycolipid metabolism in post-BS patients.
METHODS: In a 12-week RCT, 63 post-BS patients were randomized to control (standard care) or intervention (standard care+30 g/d oat bran, providing 9.0 g DF for 12 weeks). Outcomes included microbiota composition, the levels of GLP-1 and PYY, glycolipid parameters, and percentage of excess weight loss.
RESULTS: Sixty-three participants completed the trial (intervention: 30, control: 33). The intervention group achieved higher DF intake (15.28 ± 3.69 g/d vs. 7.45 ± 4.63 g/d, P < 0.05), with increased beneficial genera (Lachnospira, Parabacteroides) and reduced Streptococcus (P < 0.05). The intervention group showed significant improvements in fasting GLP-1 and PYY, FBG, and HDL-C (P < 0.05). Although the between-group difference in EWL% was not statistically significant (16.59 ± 5.87% vs 10.47 ± 3.29%, P > 0.05), both groups showed significant within-group improvements (P < 0.05). ITT analysis confirmed robustness.
CONCLUSION: DF supplementation significantly improved gut microbiota, enhanced enteroendocrine hormone secretion, and improved metabolic parameters in post-BS patients, supporting its use as an adjunctive therapy.
REGISTRATION NUMBER FOR CLINICAL TRIALS: The study protocol was registered with the Chinese Clinical Trial Registry (ChiCTR2400092481) at http://www.chictr.org.cn.
