The Role of Dietary Fiber in the Prevention and Control of Type 2 Diabetes: Clinical Evidence and Metabolic Mechanisms

Abstract

Type 2 diabetes (T2D) is a highly prevalent metabolic disease worldwide, associated with insulin resistance and impaired glycemic regulation. Dietary fiber intake has been extensively studied as a nutritional strategy for the prevention and management of T2D due to its beneficial effects on glucose metabolism. This review discusses the mechanisms by which soluble and insoluble fibers influence glycemic homeostasis, including delayed gastric emptying, modulation of the gut microbiota, production of short-chain fatty acids (SCFAs), and reduction of systemic inflammation. Additionally, clinical evidence is presented demonstrating the association between higher fiber intake and a lower risk of developing T2D, as well as improved glycemic control in individuals with diabetes. Studies suggest that a fiber-rich diet (≥ 25–30 g/day) is associated with lower fasting glucose levels, glycated hemoglobin (HbA1c), and insulin resistance. Finally, practical recommendations are provided to increase fiber consumption in the general population and at-risk groups, highlighting food sources such as whole grains, legumes, fruits, and vegetables. It is concluded that fiber inclusion in the diet represents an effective, safe, and accessible intervention for the prevention and management of T2D, reinforcing the importance of public policies and nutritional guidelines to promote its intake.