Question: How does my doctor test for a vitamin D deficiency?

Dr. Brownstein's Answer:

Vitamin D, the "sunshine vitamin," is an important vitamin. Adequate vitamin D levels are necessary for calcium absorption. Sun exposure on our skin, which provides appoximately 90 percent of the vitamin D the body needs, starts the production of vitamin D in the body. Small amounts are obtained from butter, meat, eggs, oily fish, and milk.

Presently, vitamin D deficiency is at epidemic levels in the United States, mainly because of an irrational fear of the sun. The American Medical Association, dermatologists, and the media have spread falsehoods about sun exposure resulting in an excess of melanomas and other skin cancers.

In the case of melanoma, the research has never proven a link between sun exposure and this variety of cancer. Other skin cancers have been associated with sunburns, but most can be easily treated by removing the lesion.

I believe we are seeing an increase in these superficial cancers because of a poor diet and, yes, vitamin D deficiency.

Clearly, sunscreen use has not prevented nor lowered the incidence of skin cancer over the last 20 years, even though we use record amounts of sunscreen lotions that block ultraviolet light from penetrating the skin. As a result, when you wear sunscreen, you will not produce vitamin D. This lack of vitamin D has been associated with a plethora of cancers and chronic illnesses, including breast cancer, rheumatoid arthritis, fibromyalgia, and osteoporosis.

I counsel my patients to not use sunscreen and to get 15 to 30 minutes of sunshine daily. Do not, however, allow the sun to burn your skin. Cover up when necessary.

It is important to have your doctor check vitamin D levels at least once a year. A simple blood test which checks for 25-hydroxy D3 can be done by most laboratories. My clinical experience has shown that optimal vitamin D levels range from 75 to 125 nanomoles per liter (nmol/l).