The Effect of Vitamin D3 Supplementation on Markers of Glycaemia, Lipidaemia and Oxidative Stress in Saudi Men with Poorly-Controlled Type-2 Diabetes Mellitus

Alharbi, Hend Faisal H (2018) The Effect of Vitamin D3 Supplementation on Markers of Glycaemia, Lipidaemia and Oxidative Stress in Saudi Men with Poorly-Controlled Type-2 Diabetes Mellitus. Doctoral thesis (PhD), Manchester Metropolitan University.

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Abstract

The pathogenesis of diabetes mellitus type 2 (T2DM) has been associated with vitamin D deficiency which plays a role in impaired insulin action in humans. The purpose of this research is to investigate the effect of vitamin D3 supplementation on biomarkers of glycaemia, lipidaemia and oxidative stress in Saudi men aged >18 years with poorly controlled T2DM. A double-blind, randomised, placebo-controlled, parallel trial was used to investigate 128 Saudi men with poorly-controlled T2DM randomised to receive: 1) a placebo supplement, 2) 50μg/day vitamin D3 or 3) 100μg/day vitamin D3 as capsules matched in shape and size over a 16-week period. Fasting glucose, HbA1c, fasting insulin, lipid profile, serum 25(OH)D, and total antioxidant status were measured, and advanced glycation end products (AGEs) in skin were also measured using an AGE-reader. Vitamin D supplementation of either 100μg or 50μg per day were found to give a significant improvement in the HbA1c (p<0.001) and a reduction in glucose levels (p<0.001) after 16-weeks’ intervention as compared to the placebo group in both supplementation groups. Significant reductions in total cholesterol (p<0.001) and improvements in HDL levels (p<0.001) after 16-weeks’ intervention were seen compared to the placebo group in both treatment groups. Triglycerides were significantly reduced after 16-weeks’ intervention (p<0.001) only with the higher dose of vitamin D3 (100μg/day) without any change in the 50μg/day vitamin D3 group. Vitamin D supplementation failed to demonstrate any improvement in insulin resistance, insulin secretion or oxidative stress such as total antioxidant levels or AGEs as compared to the placebo group after 16-weeks’ intervention. Vitamin D status seems to have a significant role in controlling the development and treatment of diabetes. It is likely that optimised levels of serum vitamin D may be variable between those at high risk.