There are two types of vitamin D. Ergocalciferol (Vitamin D2) is found in a few foods like fatty fish. In some countries, fruit juices, milk or cereals are often fortified with this vitamin. Cholecalciferol (Vitamin D3) is what is produced by the body when the skin is exposed to sunlight. It is difficult to get enough vitamin D through food sources. This is why sunshine is the best option. And it’s free! However, it’s not always available and air pollution is an increasing impediment to getting this vitamin from the sun.

You can get vitamin D from the sun just by spending 15 to 20 minutes a day in direct sunlight, 3 to 5 times a week. The sun’s rays should directly act upon the skin. Do not wear sunscreen during this time as this will prevent your skin from absorbing the vitamin. Vitamin D is not absorbed through clothes, windows, or even smog. That’s why it’s hard to get vitamin D from the sunshine in Indian metros.

Taking excess vitamin D supplements can cause hypervitaminosis D, which can be dangerous. However, you can never get too much vitamin D from the sun.

Do avoid sunburn by limiting exposure. If you are eating plenty of raw fruits and vegetables, the anti-oxidants in these will help prevent sunburn and also reduce the risk of skin and other cancers.

Vitamin D is stored by the body. If you have enough stored you can get by on cloudy days without any problems. If you’re concerned that you may be vitamin D deficient, and have symptoms like depression, chronic fatigue, weight loss and muscle ache get a test done to determine your level of vitamin D. In places with long winters, or cloudy or smoggy weather, it’s very important to get vitamin D levels checked. In case of deficiency, supplementation is required but even then levels should be checked to avoid over-dosage.

It is also important to note that people with darker skin tones absorb vitamin D more slowly and in lower quantities than people with light skin.

Cholecalciferol is further converted into an active form, calcitriol, mainly by the kidneys and also by a few other tissues in the body. It is possible that people with kidney disease cannot utilise cholecalciferol supplements easily and require calcitriol supplements instead.

Vitamin D is actually a hormone even though it is called a vitamin and therefore should not be in the body either in excess or lack.