Department of Clinical Nutrition, German Institute of Human Nutrition Potsdam-Rehbrücke, Arthur-Scheunert-Allee 114-116, 14558 Nuthetal, Germany.
Deutsches Zentrum für Diabetesforschung e.V., Geschäftsstelle am Helmholtz-Zentrum München, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany.
Nutrients. 2019 Oct 6;11(10):2385. doi: 10.3390/nu11102385.
High intake of cereal fibre is associated with reduced risk for type 2 diabetes and long-term complications. Within the first long-term randomized controlled trial specifically targeting cereal fibre, the Optimal Fibre Trial (OptiFiT), intake of insoluble oat fibre was shown to significantly reduce glycaemia. Previous studies suggested that this effect might be limited to subjects with impaired fasting glucose (IFG).
We stratified the OptiFiT cohort for normal and impaired fasting glucose (NFG, IFG) and conducted a secondary analysis comparing the effects of fibre supplementation between these subgroups.
180 Caucasian participants with impaired glucose tolerance (IGT) were randomized to twice-a-day fibre or placebo supplementation for 2 years ( = 89 and 91, respectively), while assuring double-blinded intervention. Fasting blood sampling, oral glucose tolerance test and full anthropometry were assessed annually. At baseline, out of 136 subjects completing the first year of intervention, 72 (54 %) showed IFG and IGT, while 64 subjects had IGT only (labelled "NFG"). Based on these two groups, we performed a stratified per-protocol analysis of glycometabolic and secondary effects during the first year of intervention.
The NFG group did not show significant differences between fibre and placebo group concerning anthropometric, glycometabolic, or other biochemical parameters. Within the IFG stratum, 2-h glucose, HbA1c, and gamma-glutamyl transferase levels decreased more in the fibre group, with a significant supplement x IFG interaction effect for HbA1c. Compared to NFG subjects, IFG subjects had larger benefits from fibre supplementation with respect to fasting glucose levels. Results were robust against adjustment for weight change and sex. An ITT analysis did not reveal any differences from the per-protocol analysis.
Although stratification resulted in relatively small subgroups, we were able to pinpoint our previous findings from the entire cohort to the IFG subgroup. Cereal fibre can beneficially affect glycemic metabolism, with most pronounced or even isolated effectiveness in subjects with impaired fasting glucose.
高摄入量的谷物纤维与 2 型糖尿病和长期并发症风险降低有关。在专门针对谷物纤维的首个长期随机对照试验中，摄入不可溶燕麦纤维显著降低了血糖。先前的研究表明，这种效果可能仅限于空腹血糖受损（IFG）的受试者。
我们对 OptiFiT 队列进行了正常和空腹血糖受损（NFG，IFG）的分层，并进行了二次分析，比较了纤维补充剂在这些亚组之间的效果。
180 名糖耐量受损（IGT）的白种人被随机分配到每天两次纤维或安慰剂补充剂组，进行为期 2 年的干预（分别为 89 人和 91 人），同时确保双盲干预。每年进行空腹采血、口服葡萄糖耐量试验和全面人体测量。在第一年干预结束时，136 名完成试验的受试者中有 72 名（54%）出现 IFG 和 IGT，而 64 名受试者仅出现 IGT（称为“NFG”）。基于这两组，我们对第一年干预期间的糖代谢和次要效果进行了分层协议分析。
NFG 组在纤维组和安慰剂组之间的人体测量、糖代谢或其他生化参数方面没有显著差异。在 IFG 组中，2 小时血糖、HbA1c 和γ-谷氨酰转移酶水平在纤维组中下降更多，HbA1c 存在补充剂 x IFG 交互作用效应。与 NFG 受试者相比，IFG 受试者从纤维补充中获得了更大的空腹血糖水平益处。结果在调整体重变化和性别后仍然稳健。意向治疗分析未显示与协议分析有任何差异。
尽管分层导致亚组相对较小，但我们能够将我们之前从整个队列中获得的发现指向 IFG 亚组。谷物纤维可以有益地影响血糖代谢，在空腹血糖受损的受试者中效果最为明显，甚至是单独的效果。
