For many years the main benefit of vitamin D was thought to be aiding in the absorption of calcium from our diets, which makes our bones strong and healthy. It is certainly true that vitamin D deficiency causes the bone weakness and deformity seen as Rickets in children. However, over the last few years, our understanding of other benefits has started to emerge. In fact, receptors for vitamin D have now been found in almost all tissue types in the body. This means that it acts within these cells, affecting a large number of bodily systems and disease risks. These are now thought to include:
- Bone health
- Cancer risk
- Heart health and blood pressure
- Diabetes risk
- Autoimmune diseases
- Neurological disorders including depression, seasonal affective disorder and dementia
What Is Vitamin D?
Vitamin D is a hormone-like substance which is unlike all other vitamins. This is because unlike other vitamins, which we must get from our diet, our bodies can actually manufacture vitamin D under the right conditions. We can still get it from the foods in our diet, but we tend to make the levels we need when our skin is exposed to sunlight.
Vitamin D is created in the body from cholesterol. It influences the entire body – receptors that respond to this vitamin have been found in almost every type of human cell, from the brain to bones.
How Much Do We Need?
Experts differ on how much vitamin D our bodies need. Pregnant and breast-feeding women, as well as the elderly should aim to maximize their levels to at least 400 IU a day. Black or Asian people are also at a recognised increased risk of deficiency because of their skin pigmentation, which protects them from the risk of skin cancer, but reduces their ability to manufacture vitamin D. Mulismahs in particular, especially those who cover completely, are also at greater risk of deficiency, and should make sure that they obtain enough vitamin D when they can.
Ways to Get Vitamin D
Vitamin D is produced naturally by the skin but only in the presence of sunlight. Sunshine contains ultraviolet light B (UVB) which converts a substance in the skin, called 7-dehydrocholesterol, into vitamin D3. This can then be converted by the liver and kidneys into the biologically active form of vitamin D.
The vitamin is also present in relatively high amounts in fish and shellfish, and in lower amounts in eggs and dairy produce.
By far the easiest and best way of delivering enough vitamin D to the body is to expose skin to direct sunlight for a few minutes each day.