Vitamin D Deficiency Concerns and Skin Cancer

Each week, Health and Beauty Expert Sue Chung will discuss skin health topics suggested by members of the HealthCentral community. To ask Sue a question, send an email to feedback@skincancerconnection.com or leave a comment below.

Reader's Question: I know a lot of doctors say avoid the sun completely, but I keep hearing that studies show a lack of vitamin D from too little sun exposure can cause cancer. How do I know how much vitamin D I'm getting is enough?

Sue's Response: First, let's clear up one point: We all agree that Vitamin D is a crucial nutrient. We all need it and our bodies suffer when we don't have enough.

What we can't seem to agree on is just how much we need to keep each part of our bodies in proper working order. In fact, within the past month, one Harvard Medical study demonstrated that a higher intake of Vitamin D and calcium could potentially reduce women's risk of breast cancer, while another study, for those concerned about Alzheimer's disease, linked higher levels of Vitamin D to a higher incidence of brain lesions in senior patients.

Unfortunately, these many conflicting opinions and the interests of pharmaceutical and cosmetic companies can cloud the main issue regarding Vitamin D and skin cancer. Some tanning salon advocates claim that the sun is the only effective source of Vitamin D, that low levels of Vitamin D will lead to other types of diseases and that people who live in less sunny climates are in more danger of suffering from Vitamin D deficiency.

While all of these claims possess a certain amount of truth, their claims are ultimately unsupported by conclusive scientific research.

Vitamin D deficiency does exist. Malnourished children can suffer from rickets, a softening of the bones, and very low levels of Vitamin D have been linked to certain kinds of cancer. However, no scientific studies conclusively prove that low levels of Vitamin D will directly cause cancer.

And while it's true that those who live in less sunny climates and those with darker skin may need a bit more sun exposure to manufacture Vitamin D, the highest overall rates of cancer occur in industrial areas with high levels of pollution and minimal levels of sunlight.

Sunlight is a known carcinogen. According to the American Cancer Society, approximately 500,000 people were diagnosed with breast, colorectal or lung cancer in 2006, compared to over one million people who were diagnosed with skin cancer. While a larger percentage of skin cancers are not life-threatening, they can still cause large amounts of discomfort and even disfiguration. And unlike most other cancers, skin cancer can be prevented by following the proper guidelines for sun protection.

Exposing yourself to excess sunlight is not the best medicine for low levels of vitamin D. Doctors now say that even a thick coat of sunscreen does not provide enough protection to warrant lying around in the sun. Sunscreens are better than nothing, but they're a poor alternative to staying out of direct sunlight. While it's impossible and impractical to avoid the sun completely, doctors advise wearing protective clothing and keeping exposure to sunlight at a bare minimum.