Effect of Short-term Vitamin D Supplementation on the Alterations of Glycemic Variables in Response to Exhaustive Eccentric Exercise in Patients with Non-alcoholic Fatty Liver

Abstract

BACKGROUND: Exhaustive eccentric exercise (EEE), along with a positive role in weight loss and physiological adaptation, increases liver enzymes and disturbs glucose homeostasis. Many studies have been considered to neutralize the adverse effects of EEE, including vitamin D (Vit D) supplementation. The present study aimed to investigate the effect of short-term Vit D supplementation on the alteration of glycemic variables in response to EEE in patients with non-alcoholic fatty liver disease (NAFLD). METHODS: In this clinical trial, 22 overweight women with NAFLD were randomly assigned to control (C; n=11) and experimental (Exp; n=11) groups. C group received a lactose placebo daily with the same color, shape, and warmth percentage; Exp group received 2000 IU of Vit D daily for 6 weeks (42 days). Blood samples were taken to measure the liver enzymes, lipid profile, and Vit D levels alteration at four stages: Pre1(before the first EEE session), post 1 (after the first EEE session), pre 2 (before the second EEE session), and post 2 (after the second EEE session). Repeated measures ANOVA and independent t test were used to analyze the data using SPSS software (version 26) at a significance level of P < 0.05. RESULTS: The results show a significant increase in glucose, insulin, and homeostatic model assessment for insulin resistance (HOMA-IR) levels in both C and Exp groups following the EEE (comparing pre 1 and post 1). Also, after 6 weeks of Vit D supplementation, glucose, insulin, and HOMA-IR increased significantly in both C (P = 0.001, P = 0.001, and P = 0.001, respectively) and Exp (P = 0.001, P = 0.001, and P = 0.001, respectively) groups following EEE (comparison of pre 2 and post 2). However, these increases were significantly lower in Exp group compared with the C group (comparing post 2). CONCLUSION: Short-term Vit D supplementation downregulates the increased glucose, insulin, and insulin resistance induced by EEE in patients with NAFLD.