Vitamin D, also known as the sunshine vitamin, can be produced in the body with mild sun exposure or 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 is suggested to supply a protective effect against multiple diseases and conditions such as cancer, type 1 diabetes and multiple sclerosis.
Vitamin D has multiple roles in the body, helping to:
– 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.
In spite of the name, vitamin D is considered a pro-hormone and not actually 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.
It is estimated that sensible 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. There are several likely factors contributing to vitamin D deficiency, which will be looked at further in this article.
The Japanese finding supports a theory that low blood levels of the sunshine vitamin occurring in winter explain why flu epidemics generally peak between December and March.
Dr. John Oxford, professor of virology at Queen Mary School of Medicine, London, said: “This is a timely study. It will be noticed by scientists. It fits in with the seasonal pattern of flu. There is an increasing background of solid science that makes the vitamin D story credible.”
Recently researchers have also pinpointed the mechanism behind vitamin D3’s ability to enhance the immune system and why it is so critical to our health. Also, vitamin D is not a vitamin, but a steroid hormone precursor, which has profound effects on innate immunity; the amount of vitamin D in most food and nearly all multivitamins is literally inconsequential.