Vitamin D₃ supplementation could improve the effect of exercise training on type 2 diabetes-induced metabolic disorders via BDNF/irisin axis in elderly women

Metabolic disorders are commonly linked to the process of aging and menopause. It is assumed that exercise and vitamin D (VitD) can have positive effects on the body, specifically via changes in irisin and brain-derived neurotrophic factors (BDNF) levels. This study aimed to investigate the concurrent effect of VitD₃ and exercise training on insulin resistance, memory performance, irisin, and serum BDNF in postmenopausal women with diabetes.

In this current study, a total of 40 participants were randomly divided into four groups: placebo, VitD₃, placebo with combined exercise, and VitD₃ with combined exercise (with each group consisting of n = 10). The exercise group underwent the respective treatments for a duration of 8 weeks. Before the implementation of interventions and 24 h after the last session, short-term/working memory performance, insulin, homeostatic model assessment–insulin resistance (HOMA), fasting blood glucose (FBG), cholesterol, low/high-density lipoprotein-cholesterol (LDL-C/HDL-C), triglyceride (TG), VitD₃ levels, fasting serum BDNF and irisin were measured.

Our data indicated the highest reduction in HOMA, insulin, cholesterol, TG, LDL-C (P < 0.001), FBG (P < 0.01), but the highest amount of increase in irisin and BDNF (P = 0.007; P = 0.004, respectively) and Digit Span Forwards and Backwards tests (P = 0.002 and P = 0.006, respectively) in VitD₃ + combined exercise compared with the placebo group.

Our findings showed that the combination of VitD₃ supplementation with combined exercise, compared with mono-therapy can effectively attenuate insulin resistance, cardiovascular risk factors, and improve memory performance in postmenopausal women diagnosed with type 2 diabetes, in part due to the signaling of BDNF and irisin.