Let the Sunshine In: Therapeutic Prospects of Vitamin D in Diabetology

Deficiency of sunshine vitamin ‘Vitamin D’ and diabetes mellitus are two common conditions encountered during clinical practice and they are widely prevalent across all ages, races, geographical regions and socioeconomic conditions [1]. More than one billion people worldwide are likely to have vitamin D deficiency due to a lack of sunshine exposure. Vitamin D (Calciferol) which comprises a group of fat soluble seco-sterols photosynthesized in the skin of vertebrates by the action of solar ultraviolet B radiation. During sun exposure, the ultraviolet B photons with energies between 290 and 315 nm are absorbed by the cutaneous 7-dehydrocholesterol to form the split sterol previtamin D3. Latitude, time of day and season of the year have a dramatic influence on the cutaneous production of vitamin D3. An increase in skin melanin pigmentation or the topical application of a sunscreen will absorb solar ultraviolet B photons and thereby significantly reduce the production of vitamin D3 in the skin. Depending on seasonal variation, it is estimated that 5 to 30 minutes of sun exposure to arms and legs during mid-day is adequate to gain D3 activity [2]. For those with fat malabsorption, which may decrease vitamin D availability, safe exposure to UVB with adherence to therapeutic protocols has been recommended to treat vitamin D deficiency [3-4]. In nature, very few foods contain vitamin D like some fish liver oils, the flesh of fatty fish, the liver and fat from aquatic mammals such as seals, polar bears and eggs from hens.