Dubbed the ‘sunshine vitamin’, Vitamin D is a fat-soluble hormone that your body can produce naturally. There are a number of forms of Vitamin D, but the two most important ones are Vitamin D2 and Vitamin D3. Vitamin D3, also known as cholecalciferol, is made by your skin naturally.
Vitamin D3 acquires hormone-like actions when cholecalciferol (Vitamin D3) is converted to 1,25-dihydroxy Vitamin D3 (Calcitriol) by the liver and kidneys. As a hormone, Calcitriol controls phosphorus, calcium, and bone metabolism and neuromuscular function.
For more than a century, scientists have recognized that Vitamin D3 is involved in bone health. Research has continued to accumulate, documenting Calcitriol’s role in the reduction of the risk of fractures to a significant degree. The latest research, however, shows that 1,25-dihyroxy Vitamin D3 deficiency is linked to a surprising number of other health conditions such as depression, back pain, cancer, both insulin resistance and pre-eclampsia during pregnancy, impaired immunity and macular degeneration.
As it becomes clear that Vitamin D3 plays a wide role in overall health, it’s becoming equally clear that a large percentage of individuals are deficient in this important nutrient, which has hormone-like activity. The fear of skin cancer has stopped many individuals from obtaining beneficial amounts of sunlight. The skin uses the energy of UVB to convert 7-dehydrocholesterol into Vitamin D3. Even individuals, who venture out into the sun often and use suntan lotion, may be deficient in Vitamin D3. Furthermore, as we age, we are less equipped to produce sufficient quantities of this vital nutrient. One study found that age-related declines in kidney function may require older people to ingest more Vitamin D3 to maintain the same blood levels as younger people.