The effect of vitamin D3 supplementation on markers of glycaemia, lipidaemia and oxidative stress in Saudi women with poorly controlled type 2 diabetes mellitus

Qadhi, Alaa Hatim (2016) The effect of vitamin D3 supplementation on markers of glycaemia, lipidaemia and oxidative stress in Saudi women with poorly controlled type 2 diabetes mellitus. Doctoral thesis (PhD), Manchester Metropolitan University.

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Abstract

Saudi Arabia has amongst the highest incidence of type 2 diabetes in the world, with nearly 20 percent of the adult population suffering from the condition. The prevalence of vitamin D deficiency in type 2 diabetics has been shown to be twice that of non-diabetic individuals. Recent studies have shown, over 95 percent of the Saudi adolescent population are vitamin D deficient. Pancreatic beta-cells express vitamin D receptors, as well as the vitamin-D3–activating enzyme 1-alpha-hydroxylase. Vitamin D plays a key role in both insulin production and glucose homeostasis. Supplementation with vitamin D could help tackle morbidity in diabetes by decreasing insulin resistance and reducing levels of advanced glycation endproducts (AGEs) which contribute to the onset and progression of diabetic complications. Despite vitamin D deficiency and diabetes being highly prevalent amongst the female Saudi population, the effect of vitamin D3 supplementation on improving diabetic outcomes is an area that is currently understudied. This was a double-blind randomized control study of 156 overweight Saudi females with poorly controlled type 2 diabetes mellitus recruited from Al-Noor Hospital in Saudi Arabia. Each subject was randomly allocated to either a placebo, 2000 IU/day or 4000 IU/day vitamin D3 intervention group for 16 weeks. Serum measurements were analysed using routine laboratory procedures. Oxidative stress biomarkers, including total antioxidant levels, were measured using a colorimetric method. AGEs were measured using an AGE reader at baseline and 16 weeks. Significant improvements in vitamin D status, HbA1c, LDL and total cholesterol were demonstrated after 16 weeks of supplementation (p < 0.001), (p = 0.001), (p = 0.028) and (p = 0.049) respectively. There were no statistically significant changes in HOMA-IR, AGE concentrations, fasting insulin, fasting glucose, HDL-cholesterol and triglyceride levels. This study suggests vitamin D may have a role in improving outcomes for type 2 diabetics and slowing the natural progression of the disease. Further research however is needed to determine the optimum dose, duration and form of delivery of supplementation in order to achieve these effects.