Within health care, there has recently been significant discussion about the importance of Vitamin D. There have been several studies that advocate for maintaining a certain level of Vitamin D in the body as it may have a positive impact on several organ systems and the immune system. Not to mention, it is critical for the utilization of calcium in our body. With these potential positive effects, the question becomes, what is the healthiest way to get Vitamin D? Essentially, there are two main ways to get Vitamin D – from diet and from the sun.
Almost daily, I have a discussion of whether we are harming ourselves by blocking this positive effect of the sun through sun protection. The answer is yes…and no. To understand the answer to this question, the Dermatology community has relied on our Anthropology colleagues to help us understand migration patterns of the human race as they relate to Vitamin D. Going back several thousand years ago, as humans migrated away from the equator, distant human populations started to select genes that created lighter skin. This process of natural selection created a genetic advantage for populations in the Northern latitudes as the level of ultraviolet light B (UVB) decreases as you get further away from the equator. UVB is the form of light that helps create Vitamin D in the skin and it is also the form of light that causes significant damage to skin cells that ultimately leads to skin cancer. Thus, with less skin pigment, the skin more readily creates Vitamin D, which is particularly important in Northern latitudes where there is limited sun, but skin cancer risk also increases.
So to answer the question of whether we are hurting ourselves by covering up in the sun, the answer is yes…if you lived in Northern Europe several hundred years ago where nutrition was poor and the sun was the best way to get Vitamin D. Also, during that time, the lifespan was much shorter than today so the negative effect of increasing skin cancer risk from the sun rarely manifested. In today’s world, this previous genetic advantage has been minimized with the rapid migration patterns that occurred over the past two hundred years. Diet and supplementation are now much safer alternatives to getting Vitamin D.
Of course there is still benefit to getting Vitamin D from the sun, but realize that you really only need minimal exposure to the sun on a day-to-day basis to get the maximum amount of Vitamin D that your body can produce. Your body can only make so much Vitamin D so there is a limit to the benefit of the sun. Additional sun exposure beyond normal daily activity in Central Oregon really just increases your risk of harm. Once again, the goal is to not completely stay out of the sun, but rather it is to be careful and avoid behaviors that are focused on getting that “perfect tan.”