There is little that is more enjoyable than getting out into the sun after a cold and grey winter. The air is fresh, the grass is green and the warm rays of sunshine seem to pull us outside. Our bodies crave the bright light. It is no wonder that light therapy is used in northern latitudes to prevent the wintertime blues known as seasonal affective disorder. We have evolved to need and love the natural light of the sun. It is a valuable source of vitamin D and among populations who live in northern latitudes there is nearly an epidemic of vitamin D deficiency.
Ten minutes of midday sunshine in the summer is equivalent to taking a dose of synthetic vitamin D. It is clear that vitamin D is important for the health of our bones, but additional research suggests vitamin D may be important for the immune system, cardiovascular health and some types of cancer such as colorectal. As with many things in life, you can get too much of a good thing.
Ten minutes of midday sunshine in the summer is equivalent to taking a dose of synthetic vitamin D.
There has been a dramatic rise in skin cancers over the last 30 years. The most common cancers are basal cell carcinoma and squamous cell carcinoma which are slow growing and typically easy to treat. Melanoma on the other hand is rising at a dramatic rate and if it is not diagnosed early it can be very difficult to control. Melanoma typically presents as an abnormal looking mole.
The ABCDE pneumonic has helped health-care providers and patients alike recognize worrisome appearing moles.
- Border irregularities
- Color variegation
- Diameter greater than six millimeters
- Evolution in color, shape or size
Worrisome lesions tend to be larger with irregular borders and may have multiple colors. If any lesion changes over time or has a tendency to bleed it should evaluated. Individuals with fair skin tones tend to burn easily and they are at greatest risk of developing melanoma. The lifetime risk of developing melanoma among Caucasians is estimated to have been 1 in 1,500 in 1935 as compared to an estimated risk of 1 in 39 among men and one in 58 among women today. This remarkable change in lifetime risk is not due solely to increased rates of screening and the identification of early and less aggressive lesions.
So how do we balance our need for vitamin D with the risk of developing skin cancer? Is there any evidence that sunscreen prevents skin cancer? It is clear that sun screen is helpful at preventing the more common and typically less life threatening, skin cancers. There are new studies emerging that suggest sunscreen may also be helpful in preventing melanoma. It is believed that the risk from sun exposure comes with intermittent and intense exposures that lead to burns. Individuals who had more than five sunburns in childhood are twice as likely to develop melanoma as an adult.
Unfortunately there is no medical consensus on the optimal amount of time to spend in the sun. It varies by an individual’s skin color, the time of the day, the geographic location, the season of the year and the weather.
The ultraviolet radiation from the sun is divided into UV-A and UV-B. We know that UV-B poses a greater risk for melanoma. Is it safe to get that bronze tan from a tanning bed that uses only UV-A light? There are now multiple studies demonstrating that tanning beds increase an individual’s risk of developing melanoma. In 2009, the World Health Organization classified ultraviolet light from tanning beds as a human carcinogen. This carcinogen was used by one third of women aged 18 to 25 in the United States in 2010. Are we doomed to be deficient in vitamin D if we can’t get our sun? This question has generated a great deal of controversy given the importance of vitamin D to overall health.
Sunscreen effectively blocks the harmful UV-B rays of the sun and an SPF-30 screen can decrease vitamin D production by 95 percent. As with many things in life the balance of adequate sun intake and avoidance of sun damage requires careful consideration. Spending as little as three to six minutes in the sun may be adequate for vitamin D synthesis in fair skinned individuals, but among those who are sensitive to the sun this could lead to a burn. Unfortunately there is no consensus on the optimal amount of time to spend in the sun. It varies by an individual’s skin color, the time of the day, the geographic location, the season of the year and the weather.
The points to take away are that melanoma is on the rise and ultraviolet radiation from the sun is a risk factor. Intermittent and intense sun exposures that cause burns should be avoided. Some direct sun exposure, but not too much, is ideal. The vast majority of time spent in the sun should be done with adequate protection. Among individuals who burn easily, live in northern latitudes or get minimal sun exposure a vitamin D supplement should be considered after discussion with a physician.