Find The Balance In Sunbathing

July 24, 2014


Exposure to the sun is the best way to get your vitamin D, and several studies show that those who shun the rays are at much greater risk of developing vitamin D deficiencies. Yet national guidelines encourage us to lather on sunscreen or avoid the sun to decrease the risk of developing skin cancer.

The answer may literally be skin deep; the color of your coating determines the tipping point between health benefit and health risk.

The most recent study to enter the debate comes from Sweden, a country with limited sunshine and a low UV index. Almost 30,000 women were followed over a 20-year period and were asked to fill out a survey on sun exposure, smoking habits, education, number of pregnancies, marital status, exercise habits, income, and weight.


After taking everything into account, the researchers observed that women who got the most sun had the greatest risk of developing skin cancer. But compared to that group, the risk of dying from everything else was twice as great among the sun avoiders — 40% in those with moderate sun exposure.

Generally speaking, the sun avoiders died of other ailments than skin cancer. One of the main limitations of this study was that participants’ vitamin D levels were not measured. They nevertheless attributed their findings to low vitamin D levels, a condition that increases the risk of developing bone disease, cardiovascular disease, diabetes, and certain cancers.

The findings eloquently illustrate the D dilemma that has scientists on one side arguing that shielding yourself from UV rays is detrimental to your health, with dermatologists on the other urging people to avoid sun exposure at all cost. Somewhere in the middle lies the true debate: How much sun exposure is safe enough to synthesize adequate amounts of vitamin D?


Our skin reacts to mild doses of UV radiation by increasing the amount of protective melanin in the skin’s outer layers. Too much UV in too short a time, however, can result in cellular damage from radiation burn — essentially the difference between a suntan and sunburn.

Thankfully, the ozone layer in Earth’s atmosphere absorbs the greater part of the most damaging UV wavelengths, but some do get through, and these are responsible for long-term skin damage and skin cancer.

Melanin is a pigment that is able to absorb light and dissipate 99.9% of absorbed UV radiation, and it is therefore able to reduce the risk of malignant melanoma, the most dangerous form of skin cancer.

Studies show that individuals with more concentrated melanin have lower incidences of skin cancer.

This was perfect for our common ancestors who lived in sub-Saharan Africa, but things got complicated when we decided to explore and settle in more northern and southern latitudes.