Vitamin D is an essential vitamin that we get from some food; but it's unique in that our bodies also manufacture it in response to the skin’s exposure to sunlight.
Vitamin D is vital for strong bones. It helps with the absorption of calcium and is need for bone growth and repair. Too little Vitamin D can result in soft bones in children (rickets) and an increased risk for fractures and brittle bones in older people.
Vitamin D is also crucial to the health of your heart. Studies show that a deficit in the sunshine vitamin can increase your risk for heart disease, heart attack and stroke.
Low Vitamin D-levels have been linked to cancers of the colon, breast and prostate, as well as the development of diabetes and multiple sclerosis (a chronic disease of the nervous system).
Researchers in the multiple sclerosis (MS) field are interested in Vitamin D because it has long been known that MS occurs more commonly in populations who live in countries far from the equator where they're exposed to lower levels of sunlight. This suggests that there might be a link between Vitamin D deficiency and the risk of developing MS.
Some recent research suggests that a lack of Vitamin D in early childhood or even in-utero (in the womb) may up the risk for developing MS later in adulthood.
A study in the journal JAMA Neurology found that babies born in London in May (i.e. the pregnancy was mainly during the northern hemisphere winter months) have significantly lower levels of Vitamin D and a potentially greater risk for developing MS than babies born in November (after a summer pregnancy). The mothers whose babies were born in May likely had more exposure to sunlight, and had higher levels of Vitamin D.
Can Vitamin D relieve MS symptoms?
Medical scientists don't yet know whether higher intakes of Vitamin D can help manage MS in people who already have the disease. Some studies have suggested that it may be helpful, but there is no scientific consensus yet.
In the meantime, it’s a good idea to have a blood test to see if you have a deficiency.
Adequate Vitamin D is important for everyone’s general health: among other benefits, it helps stave off osteoporosis and heart disease, and plays a role in the correct functioning of the immune system.
A good dose
The most efficient way to get enough Vitamin D is from exposure to sunlight a day (on bare skin outside). About 15 minutes of sunlight a day is enough, but don't forget the sunblock!
Getting Vitamin D from food is much less efficient, but good dietary sources include oily fish, fortified cereals, eggs and margarine. (Oily fish has loads of other health benefits too.)
Vitamin D can also be taken as a supplement. Never take more than the dose recommended by your doctor, however (of Vitamin D or any supplement). Also note that taking Vitamin D supplements together with cod liver oil can result in an overly-high intake.