Carbohydrate-Restricted Diet may Improve Beta-Cell Function in Type 2 Diabetes Patients: Study

Beta-cell dysfunction is an important determinant in the mechanism of developing type 2 diabetes by losing first-phase insulin response. Led by Marian Yurchishin, MS, a PhD student at the University of Alabama at Birmingham, a new study aimed to determine if a carbohydrate-restricted diet could enhance beta-cell function over a short period of intervention. The researchers' hypothesis was based on the belief that decreasing glucose exposure-to what is considered "glucose toxicity" for the beta cell-may allow for repair and restoration of cell function.

The study consisted of 57 patients with type 2 diabetes who were not on insulin therapy. Ninety-three participants were randomized to a carbohydrate-restricted diet (9% of energy from carbohydrates, 65% from fats) or a higher-carbohydrate diet (55% energy from carbohydrates, 20% from fats). The carbohydrate-restricted group included 5 men and 22 women; mean age 53 years, 17 Black and 10 white. The higher-carbohydrate group included 8 men and 22 women; mean age 55 years, 20 Black and 10 white.

At 12 weeks, the authors noted marked increases in beta-cell function in the carbohydrate-restricted diet group:

• The acute C-peptide response was twice as large in the carbohydrate-restricted group compared with the higher-carbohydrate group (p < 0.01).

• The maximal C-peptide response, an index of the beta-cell's ability to produce insulin, was 22% larger in the carbohydrate-restricted group (p < 0.05).

• Disposition index, a marker of insulin sensitivity and secretion, was 32% higher in the carbohydrate-restricted group compared with the oral glucose tolerance test (p< 0.05).

• The study also noted race differences in beta-cell function. Maximum C-peptide response was 48% higher in white patients on the carbohydrate-restricted diet compared with those on the higher-carbohydrate diet (p< 0.01), but not in Black patients. This suggests that mechanisms that lead to beta-cell failure may vary by race.

Carbohydrate restriction ameliorates the function of white subjects' beta cells, particularly of type 2 diabetic subjects. Such a dietary intervention may potentially enhance glycemic control and improve insulin secretions at least in the absence of weight loss. However, the racial differences in beta-cell recovery bode well for further research in the mechanisms that underlie such disparities.

Reference:

Swain, E. (2024, October 22). Effects of a Carbohydrate Restricted Diet on Beta-cell Response in Adults with Type 2 Diabetes, Journal of Clinical Endocrinology & Metabolism (2024). dx.doi.org/10.1210/clinem/dgae670