Sunscreen: yes and no

A consortium of public health groups in Australia, whose predominantly white population has by far the world’s highest rate of skin cancer, issued a new position statement: “Completely avoiding sun exposure is not optimal for health.” Too much shade can be just as harmful as too much sun. That’s because sun exposure triggers vitamin D production in the skin, and low levels of vitamin D are associated with increased rates of stroke, heart attack, diabetes, cancer, Alzheimer’s, depression, osteoporosis, and many other diseases.

Vitamin D in a pill is no solution. In fact, it has turned out to be a spectacular failure. In a five-year trial of 26,000 older adults, The New England Journal of Medicine reported no benefits whatsoever in any of the health conditions that the study tracked, including cardiovascular disease, prevention of falls, age-related macular degeneration, and a host of other diseases. The final word: “People should stop taking vitamin D supplements to prevent major diseases or extend life.” You must get your vitamin D from the sun.

People at higher latitudes (less sun) suffer from higher rates of many diseases than people living at low or middle latitudes. This difference is most pronounced in autoimmune disorders, especially multiple sclerosis. That’s because UV light retards the immune system’s attack on cells, tamping down inflammation. Diseases now believed to be connected to chronic inflammation, including cardiovascular disease and Alzheimer’s, are often less prevalent in regions with more sun exposure. Also, bright morning light, filtered through our eyes, helps regulate our circadian rhythms, improving energy, mood and sleep.

Bottom line: UV light is both harmful and beneficial, so the trick is to find a balance between too much sun and not enough. In Australia, experts have come up with an approach that divides its sunscreen recommendations into groups according to skin color and susceptibility to skin cancer. Depending on your skin type, length of exposure, and the UV index for the day, you may need a lot of sunscreen or you may need none. It’s a customized solution.

Health authorities in some countries are beginning to follow Australia’s lead. In the U.S., dermatologists are sticking with their always sunscreen approach. As for myself, I never use sunscreen, mostly because of laziness. Of course, I’ve had plenty of skin cancer, but I don’t have the other diseases associated with a lack of vitamin D—yet.

For an introduction to this blog, see I Just Say No; for a list of blog topics, click the Topics tab.