Longitudinal associations of dietary fiber and its source with 48-week weight loss maintenance, cardiometabolic risk factors and glycemic status under metformin or acarbose treatment: a secondary analysis of the March randomized trial

AIMS: To examine longitudinal and dose-dependent associations between dietary fiber intake and various clinical outcomes over 48 weeks of pharmacological treatment in T2DM patients. METHODS: This secondary analysis used data from the MARCH trial comparing acarbose versus metformin monotherapy as initial therapy in Chinese patients newly diagnosed with T2DM. Dietary intakes were assessed by 24-h dietary recall, evaluating total fiber and fibers from specific sources as well as the carbohydrate-to-fiber ratio. RESULTS: Among 551 patients with complete dietary records (286 acarbose; 265 metformin), higher intakes of total and whole grain fiber were associated with better β-cell function, insulin sensitivity, and postprandial glycemic control under acarbose. Higher legume fiber intake was associated with better glycemic control in both groups, and with greater weight loss only under metformin. A high-carbohydrate–low-fiber diet was associated with worse glycemic control and lower HDL-C under acarbose, but with higher insulin sensitivity and better weight loss under metformin. CONCLUSIONS: The notable effects of various dietary fibers in combination with different oral glucose-lowering medications should be considered to maximize therapeutic benefit.

Jia Liu, Yu An, Ning Yang, Yuan Xu, Guang Wang