Let The Sun Shine In?

I recently returned from a beach vacation.  One of our daily rituals was slathering on SPF 50 sunscreen to try to protect ourselves against the blazing sunshine.  We wanted to be in the warm sun rather than the gray cold Midwest, obviously, but we’d accepted the healthcare cautions about sunshine and skin cancer, and so the sunblock went on.

But what if the healthcare cautions that led to our lubing up are wrong — as in, 180-degree wrong?  What if exposure to sunshine is not only not bad for you, but in fact it helps you to be healthier in countless ways, by effectively and efficiently producing vitamin D, lowering blood pressure, making you feel happier, and having other therapeutic benefits?

That’s the intriguing conclusion of recent research that started with a look at the value of vitamin D supplements — which many people who avoid the sun are taking to try to compensate for the lack of solar-produced vitamin D.  Low vitamin D levels are associated with lots of bad stuff — cancer, diabetes, obesity, osteoporosis, heart attack, stroke, depression, cognitive impairment, autoimmune conditions — and vitamin D is required for calcium absorption and good bone health.  So vitamin D supplements should help, right?  But the research showed that vitamin D supplements weren’t having any discernible impact on cancer, heart disease, or stroke.

Scientists scratched their heads and looked into the unexpected result, and started to find evidence that it wasn’t high vitamin D levels that prevented the bad conditions.  Instead, the presence of vitamin D was just a marker, and the real cause for the positive health effects was that sunlight that was producing the vitamin D.  The people who had the high vitamin D and were avoiding the bad conditions were getting plenty of sunlight.  Exposure to sunshine also causes the skin to produce nitric oxide, which dilates blood vessels and reduces blood pressure — which, as the article linked above points out, helps to explain why “rates of high blood pressure, heart disease, stroke, and overall mortality all rise the farther you get from the sunny equator, and they all rise in the darker months.”

And the vitamin D/blood pressure effects may just be the start.  The article continues:  “Sunlight triggers the release of a number of other important compounds in the body, not only nitric oxide but also serotonin and endorphins. It reduces the risk of prostate, breast, colorectal, and pancreatic cancers. It improves circadian rhythms. It reduces inflammation and dampens autoimmune responses. It improves virtually every mental condition you can think of. And it’s free.”

But wait — won’t getting more sunshine cause skin cancer?  Yes, there is that risk — but the article points out that skin cancer is not nearly as lethal as the other diseases and conditions that exposure to sunlight helps prevent.  And, additionally, people who regularly get sunshine, avoid sunburns, and keep their tans going — like outdoor workers — are much less likely to experience melanoma, the less-common but potentially fatal kind of skin cancer.  In fact, the evidence indicates that long-term exposure to sun is associated with lower melanoma rates.

All of this will come as a surprise to people who are scared to death of skin cancer and buy sunblock by the carload, but it makes sense from an evolutionary standpoint.  Our half-naked distant ancestors didn’t have SPF50 to apply, and they were exposed to the sun on a much more prolonged basis than modern, largely indoor humans.  It makes sense that humans would evolve in ways that would favor those who were more efficient in using that abundant, constant sunshine in positive, healthy ways.

Think about that the next time you’re carefully applying that SPF50 sunblock and popping down vitamin D pills.