Do We Really Need Sun Protection?

For years, we’ve been told to stay out of the sun and use sunscreen. Those guidelines may not only be unnecessary—they also could be harming our overall health.

- By Rowan Jacobsen

These are dark days for supplements. Although they are a $30-billion-plus market in the United States alone, some of them, such as vitamin A, selenium, glucosamine, chondroitin, and fish oil, have now flopped in study after study.

If there was one supplement that seemed sure to survive the rigorous tests, it was vitamin D. People with low levels of vitamin D in their blood have significantly higher rates of virtually every disease you can think of: cancer, diabetes, obesity, osteoporosis, heart attack, stroke, depression, cognitive impairment, autoimmune conditions, and more. Vitamin D deficiency is even suspected of being a factor in severe COVID-19 cases.

Health experts believe that most of us aren’t getting enough of this essential vitamin. Vitamin D is a hormone manufactured by the skin with the help of sunlight. It’s difficult to obtain in sufficient quantities through diet. When our ancestors lived outdoors in tropical regions and ran around half-naked, this wasn’t a problem. They produced all the vitamin D they needed from the sun.

But today, 90 percent of us spend about 22 hours indoors every day, according to EPA research. And when we do go outside, we’ve been taught to slather on sunscreen to protect ourselves from dangerous UV rays, which can cause skin cancer. Sunscreen can reduce our natural production of vitamin D, so we’ve been told to compensate with vitamin D pills.

Yet vitamin D supplementation has failed in clinical trials. One of the largest trials ever conducted—in which 25,871 participants received high doses for five years—found no impact on cancer, heart disease, or stroke.