School of Public Health, Fudan University, 138 Yi Xue Yuan Road, Shanghai 200032, China.
Yiwu Research Institite, Fudan University, Building V of Zhongfu Square, Yiwu 322000, China.
Nutrients. 2022 Feb 27;14(5):1003. doi: 10.3390/nu14051003.
High-fiber diet interventions have been proven to be beneficial for gut microbiota and glycemic control in diabetes patients. However, the effect of a low level of fiber in habitual diets remains unclear. This study aims to examine the associations of habitual dietary fiber intake with gut microbiome profiles among Chinese diabetes patients and identify differential taxa that mediated associations of dietary fiber with HbA1c level. Two cross-sectional studies and one longitudinal study were designed based on two follow-up surveys in a randomized trial conducted during 2015−2017. The study included 356 and 310 participants in the first and second follow-ups, respectively, with 293 participants in common in both surveys. Dietary fiber intake was calculated based on a 3-day 24-h diet recall at each survey and was classified into a lower or a higher group according to the levels taken based on the two surveys using 7.2 g/day as a cut-off value. HbA1c was assayed to assess glycemic status using a cut-off point of 7.0% and 8.0%. Microbiome was profiled by 16S rRNA sequencing. A high habitual dietary fiber intake was associated with a decrease in α-diversity in both the cross-sectional and longitudinal analyses. At the first follow−up, phylum Firmicutes and Fusobacteria were negatively associated with a higher dietary fiber intake (p < 0.05, Q < 0.15); at the second follow-up, genus Adlercreutzia, Prevotella, Ruminococcus, and Desulfovibrio were less abundant in patients taking higher dietary fiber (p < 0.05, Q < 0.15); genus Desulfovibrio and Ruminococcaceae (Unknown), two identified differential taxa by HbA1c level, were negatively associated with dietary fiber intake in both the cross-sectional and longitudinal analyses, and mediated the dietary fiber-HbA1c associations among patients taking dietary fiber ≥ 7.2 g/day (mediation effect β [95%CI]: −0.019 [−0.043, −0.003], p = 0.018 and −0.019 [−0.046, −0.003], p = 0.016). Our results suggest that habitual dietary fiber intake has a beneficial effect on gut microbiota in Chinese diabetes patients. Further studies are needed to confirm our results.
高纤维饮食干预已被证明对糖尿病患者的肠道微生物群和血糖控制有益。然而，习惯性饮食中纤维含量低的影响仍不清楚。本研究旨在研究中国糖尿病患者习惯性膳食纤维摄入量与肠道微生物组谱之间的关系，并确定介导膳食纤维与 HbA1c 水平关联的差异分类群。基于 2015-2017 年期间进行的一项随机试验的两次随访，设计了两项横断面研究和一项纵向研究。第一项和第二项随访分别纳入了 356 名和 310 名参与者，其中 293 名参与者在两次调查中均有。膳食纤维摄入量根据每次调查的 3 天 24 小时饮食回忆计算，并根据两次调查的水平，使用 7.2 g/天作为截止值，将其分为较低或较高组。使用 7.0%和 8.0%的切点测定 HbA1c 以评估血糖状态。通过 16S rRNA 测序对微生物组进行分析。在横断面和纵向分析中，高习惯性膳食纤维摄入量与 α 多样性降低有关。在第一次随访时，厚壁菌门和梭杆菌门与较高的膳食纤维摄入量呈负相关（p<0.05，Q<0.15）；在第二次随访时，更高膳食纤维摄入量的患者中属 Adlercreutzia、Prevotella、Ruminococcus 和 Desulfovibrio 的丰度较低（p<0.05，Q<0.15）；在横断面和纵向分析中，鉴定出的两个差异分类群，属 Desulfovibrio 和 Ruminococcaceae（未知），与膳食纤维摄入量呈负相关，并且介导了膳食纤维摄入量≥7.2 g/天的患者中膳食纤维与 HbA1c 的关联（介导效应β[95%CI]：−0.019[−0.043，−0.003]，p=0.018 和−0.019[−0.046，−0.003]，p=0.016）。我们的结果表明，习惯性膳食纤维摄入对中国糖尿病患者的肠道微生物群有益。需要进一步的研究来证实我们的结果。
