Role of vitamin D in the pathogenesis of type 2 diabetes mellitus

Abstract

Vitamin D deficiency has been shown to alter insulin synthesis and secretion in both humans and animal models. It has been reported that vitamin D deficiency may predispose to glucose intolerance, altered insulin secretion and type 2 diabetes mellitus. Vitamin D replenishment improves glycaemia and insulin secretion in patients with type 2 diabetes with established hypovitaminosis D, thereby suggesting a role for vitamin D in the pathogenesis of type 2 diabetes mellitus. The presence of vitamin D receptors (VDR) and vitamin D-binding proteins (DBP) in pancreatic tissue and the relationship between certain allelic variations in the VDR and DBP genes with glucose tolerance and insulin secretion have further supported this hypothesis. The mechanism of action of vitamin D in type 2 diabetes is thought to be mediated not only through regulation of plasma calcium levels, which regulate insulin synthesis and secretion, but also through a direct action on pancreatic b-cell function. Therefore, owing to its increasing relevance, this review focuses on the role of vitamin D in the pathogenesis of type 2 diabetes mellitus.

Evaluation of 25(OH) Vitamin D 3 with Reference to Magnesium Status and Insulin Resistance in T2DM

“…Vitamin D is stored in inactive form in liver and adipose tissue. The activation of Vitamin D (hydroxylation reaction) occurs in liver and kidneys and finally gets activated to calcitriol (1,25 DHCC) [22]. In healthy subjects, Vitamin D deficiency occurs mainly because of low dietary intake and less exposure to sunlight.…”

Vitamin D and Spectrum of Its Roles

“…Data from various epidemiological studies have suggested that there is link between vitamin D3 and development of type 1 diabetes [12,13]. Literature also reports the vitamin D receptor gene polymorphism in relation with type 1 diabetes [14,15]. Studies reveal the association between vitamin D and β cell function, insulin secretion and its action.…”

Vitamin D and diabetes: the devil is in the D-tails

“…Here we are limited to small interventions and animal studies. In type 2 diabetes very high doses of 25-(OH)D have been administered, but the data are confusing, whereas in type 1 diabetes 1,25-(OH)2D has mainly been given, with little or no effect on C-peptide preservation in newly diagnosed type 1 patients [7,8]. What about NOD mice?…”