Well what we are really talking about here is Vitamin D. Vitamin D is really a group of fat-soluble (dissolve in oil not water) vitamins that help the intestines absorb minerals like calcium, magnesium, phosphorous, iron and zinc. It helps maintain proper blood concentrations of calcium and is important for bone health. It is also very important for cell growth and is needed by your muscles and nerves to function properly. Vitamin D also plays a role in immune function where it reduces inflammation.
So where do you get such an important vitamin. Well, despite its importance, very few foods contain Vitamin D. It is mainly found in the fat of fish. Beef liver and egg yolks have small amounts. It is however, added into many of our foods, milk being the most common. The good news is you make it yourself in your skin with the help of the sun! That is why it is often called the sunshine vitamin.
An article published in the British Medical Journal last year reviewed the medical evidence looking for a correlation (connection) between Vitamin D levels and the risk of death from cardiovascular (heart) disease, cancer and other causes of death. It found that mortality (death) rates increased as Vitamin D levels decreased. The authors recommended further studies to determine if an optimal dose and duration of supplementation of Vitamin D could be established.
Until such studies are performed and the results are available, should you avoid the sun or not? First step first. Your heath care provider can order a blood test to determine if your Vitamin D level is adequate. He or she can then recommend supplementation with Vitamin D3 if necessary. The current recommendations for oral supplementation vary depending on whom you consult because of the evolving research on the importance of vitamin D. For example, the Vitamin D Council has adopted the higher dosing for the recommended daily intakes while the Endocrine Society still reserves these doses for the maximum safe daily doses. If you are going to be out in the sun, you will make some Vitamin D. Depending on cloud cover, your skin color and whether or not you are wearing sunscreen, your body can synthesize the Vitamin D you need with about 5-30 minutes of sun exposure between the hours of 10 am and 3pm twice a week. But remember, the sun is also a carcinogen. It causes cancer. You need to protect your skin. Increasing your Vitamin D level naturally at the risk of getting skin cancer gets you nowhere. For more information on Vitamin D, see the first link from the NIH. The second link is to the Vitamin D Council and the third link is to the BMJ article.