在肠易激综合征患者中进行的淀粉和蔗糖减少的饮食干预导致肠道微生物群落组成发生变化，同时门、属和扩增子序列变异丰度也发生变化，但不会影响 micro-RNA 水平。

BACKGROUND/AIM: A randomized clinical trial with a starch- and sucrose-reduced diet (SSRD) in irritable bowel syndrome (IBS) patients has shown clear improvement of participants' symptoms. The present study aimed to explore the effects of the SSRD on the gut microbiota and circulating micro-RNA in relation to nutrient intake and gastrointestinal symptoms. METHODS: IBS patients were randomized to a 4-week SSRD intervention (n = 80) or control group (n = 25); habitual diet). At baseline and 4 weeks, blood and fecal samples, 4 day-dietary records, and symptom questionnaires were collected, that is, Rome IV questionnaires, IBS-symptom severity score (IBS-SSS) and visual analog scale for IBS (VAS-IBS). Micro-RNA was analyzed in blood and microbiota in faeces by 16S rRNA from regions V1-V2. RESULTS: The alpha diversity was unaffected, whereas beta diversity was decreased (p < 0.001) along with increased abundance of Proteobacteria (p = 0.0036) and decreased abundance of Bacteroidetes phyla (p < 0.001) in the intervention group at 4 weeks. Few changes were noted in the controls. The shift in beta diversity and phyla abundance correlated with decreased intakes of carbohydrates, disaccharides, and starch and increased fat and protein intakes. Proteobacteria abundance also correlated positively (R = 0.07, p = 0.0016), and Bacteroidetes negatively (R = 0.07, p = 0.0017), with reduced total IBS-SSS. Specific genera, for example, Eubacterium eligens, Lachnospiraceae UCG-001, Victivallis, and Lachnospira increased significantly in the intervention group (p < 0.001 for all), whereas Marvinbryantia, DTU089 (Ruminoccocaceae family), Enterorhabdus, and Olsenella decreased, together with changes in amplicon sequence variant (ASV) levels. Modest changes of genus and ASV abundance were observed in the control group. No changes were observed in micro-RNA expression in either group. CONCLUSION: The SSRD induced a shift in beta diversity along with several bacteria at different levels, associated with changes in nutrient intakes and reduced gastrointestinal symptoms. No corresponding changes were observed in the control group. Neither the nutrient intake nor the microbiota changes affected micro-RNA expression. The study was registered at ClinicalTrials.gov data base (NCT03306381).

背景/目的：一项针对肠易激综合征（IBS）患者的淀粉和蔗糖减少饮食（SSRD）的随机临床试验显示，参与者的症状明显改善。本研究旨在探讨 SSDR 对肠道微生物群和循环 micro-RNA 的影响，以及与营养摄入和胃肠道症状的关系。

方法：将 IBS 患者随机分为 4 周 SSDR 干预组（n=80）或对照组（n=25）；习惯性饮食）。在基线和 4 周时，采集血样和粪便样本、4 天饮食记录和罗马 IV 问卷、IBS 症状严重程度评分（IBS-SSS）和 IBS 视觉模拟评分（VAS-IBS）。通过 16S rRNA 从 V1-V2 区域分析血液中的 micro-RNA 和粪便中的微生物群。

结果：干预组第 4 周时 alpha 多样性不受影响，而 beta 多样性下降（p<0.001），同时 Proteobacteria 的丰度增加（p=0.0036），Bacteroidetes 门的丰度降低（p<0.001）。对照组的变化较小。beta 多样性和菌群丰度的变化与碳水化合物、二糖和淀粉摄入量的减少以及脂肪和蛋白质摄入量的增加有关。变形菌的丰度也呈正相关（R=0.07，p=0.0016），拟杆菌呈负相关（R=0.07，p=0.0017），与总 IBS-SSS 降低相关。在干预组中，特定的属，如 Eubacterium eligens、Lachnospiraceae UCG-001、Victivallis 和 Lachnospira 显著增加（所有 p<0.001），而 Marvinbryantia、DTU089（Ruminoccocaceae 家族）、Enterorhabdus 和 Olsenella 减少，与扩增子序列变异（ASV）水平的变化有关。对照组也观察到属和 ASV 丰度的适度变化。两组的 micro-RNA 表达均无变化。

结论：SSRD 诱导了 beta 多样性的变化，同时也引起了不同层次的几种细菌的变化，与营养摄入的变化和胃肠道症状的减轻有关。对照组没有观察到相应的变化。营养摄入或微生物群的变化都没有影响 micro-RNA 的表达。该研究在 ClinicalTrials.gov 数据库注册（NCT03306381）。