A group of fat-soluble prohormones, that help greatly in the absorption and use of calcium and magnesium in the body, is collectively called Vitamin D. Sunlight is a rich and natural source of Vitamin D. Exposure to sunlight facilitates the synthesis of vitamin D by the skin.
There are five types of Vitamin D – D1, D2, D3, D4, and D5. Among them, those useful and necessary for humans are the two types D2 (ergocalciferol) and D3 (cholecalciferol).
Importance
Vitamin D is important for us because it helps
- Strengthen the immune system
- Maintain healthy body weight
- Protect the body from harmful radiation to a small extent
- Keep the brain healthy
- Reduce symptoms of asthma
- Decrease the risk of cancer, rheumatoid arthritis, and multiple sclerosis
- Metabolism of calcium and magnesium to build healthy bones
For those who cannot absorb Vitamin D the natural way supplements are recommended because Vitamin D is an important nutrient. A National Health and Nutrition Examination Survey conducted some years ago found that, among the 6000 children (aged between 1- 21 years) a huge 61 % were Vitamin D insufficient and 9% were Vitamin D deficient. This is cause for great concern as

Low levels of Vitamin D
Reduced levels of the nutrient causes
- Low HDL levels (HDL is the “good” cholesterol)
- Increased risk for heart disease
- Increased risk of rickets, a bone disease
- Low calcium levels and consequent deterioration of bone strength
- Increased systolic count of blood pressure
A person needs a minimum of 10 to 15 minutes of exposure to sunlight, twice every 7 days in order to build the required amount of Vitamin D for the body. But if people live at a distance from the equator ( in the Arctic region for example) or if there are incidences of cloud cover and smog then exposure to the sun’s rays is difficult.
This is when Vitamin D supplements are needed. Children unable to receive Vitamin D directly from sunlight, and people with a high level of Vitamin D deficiency will need a supplement that gives them 1000 IUs (International Units) per day. Older people and dark-skinned people also need high levels of Vitamin D. Vitamin D supplementing is recommended for babies a few days after birth.
There are Vitamin D fortified foods all over the world today to combat the high prevalence Vitamin D deficiency. These include cereals, dairy products with milk on top of the list, oil spreads, breads, margarine and milk. Further studies now proved that the foods fortified with Vitamin D were not helping a section of people who still were Vitamin D deficient. Supplements have been recommended by physicians for such people.