Vitamin D, the sunshine vitamin, is produced in the body with mild sun exposure or can be consumed in food or supplements.
Adequate vitamin D intake is important for the regulation of calcium and phosphorus absorption, maintenance of healthy bones and teeth, and it is supposed to have a protective effect against multiple diseases and conditions such as cancer, diabetes type 1 and multiple sclerosis.
Vitamin D is a pro-hormone and not a vitamin. This is because the body is capable of producing its own vitamin D through the action of sunlight on the skin, while vitamins are nutrients that cannot be synthesized by the body and must be acquired through the diet or supplements.
Vitamin D has multiple roles
- Maintain the health of bones and teeth
- Support the health of the immune system, brain and nervous system
- Regulate insulin levels and aid diabetes management
- Support lung function and cardiovascular health
- Influence the expression of genes involved in cancer development.
It is estimated that sun exposure on bare skin for 5-10 minutes 2-3 times per week allows the body the ability to produce sufficient vitamin D, but vitamin D has a half-life of only two weeks, meaning that stores can run low, especially in winter. Recent studies have suggested that up to 50% of adults and children worldwide are vitamin D deficient.
Vitamin D is produced when sunlight converts cholesterol on the skin into calciol (vitamin D3). Vitamin D3 is then converted into calcidiol (25-hydroxyvitamin D3) in the liver. The kidneys then convert calcidiol into the active form of vitamin D, called calcitriol (1,25-hydroxyvitamin D3). As such, statins and other medications or supplements that inhibit cholesterol synthesis, liver function or kidney function can impair the synthesis of vitamin D.
Some Facts about Vitamin D
- Vitamin D’s primary role is to support the development and maintenance of bones and teeth.
- Vitamin D deficiency is common, especially in the elderly, infants, people with dark skin and people living at higher latitudes or who get little sun exposure.
- Vitamin D deficiency has been seen in up to 80% of hip fracture patients.
- 800IU of vitamin D per day reduces the risk of fracture by 20% in the elderly and decreases the risk of falls.
- The metabolism of vitamin D may be affected by some medications, including barbiturates, phenobarbital, dilantin, isoniazid and statin drugs.