SUNLIGHT HAS BEEN around a lot longer than we have. So why is it such a polarizing topic now, between the “never let a stray ray hit your unprotected skin. Wear sunscreen indoors” messages and the ones that tell us that sunscreen causes cancer and that there’s been an “aggressive suppression” of sunlight by the government.
Rowan Jacobsen took it all on for his new book, In Defense of Sunlight, and uncovered the nuance, the misunderstandings, and the weirdly simple—but heretical sounding—truths. Like how a moderate amount of chronic daily sun exposure (without sunscreen—gasp!) is actually good for us.
“We have a ton of epidemiological evidence that’s accumulated over decades showing that people who get at least moderate amounts of sunlight have lower mortality and higher longevity than people who don’t,” he says. And those are studies that have controlled for exercise, diet, socioeconomics and all the other usual confounding variables.
When sun hits sunscreen-free skin, for instance, it can help lower blood pressure via nitric oxide. And of course, you make Vitamin D. “It’s one of the key molecules that marshals the body’s defenses against free radicals and against damaged cells,” he explains, making it an anti-cancer and anti-inflammation molecule. And there are plenty more ways the many wavelengths of natural light affect us.
“A basic grappling with the science hadn’t happened on this subject in a long time,” he says, and the result is a surprising look at all the sun science and the people driving it.
We caught up with him before the book’s launch to topline some of the basics:
A Bigger Danger than a Little Sun is Staying Indoors All the Time
SKIN CANCER WAS a rarity before the 20th century. After World War II, it went way up.
and like it’s actually laughable when you look back at the official papers on this stuff, showing that the official word is that that rise is entirely due to sun. It was as if our ancestors, until WWII, never exposed their skin to sunlight. Makes no sense.
All you have to do, is look at a picture of Coney Island, circa 1935—everybody is running around in bikinis, basically. Weirdly, the rise of skin cancer tracks with the rise of sunscreen. But it also tracks with a plunge in the amount of time we’re all spending outside, and there’s been pretty good data on that.
So, obviously, it’s not as simple as too much sunlight is triggering this explosion in skin cancer. Something about our lifestyles changed in the 20th Century that is responsible. Sun is obviously a factor in that, but people were running around for millions of years, and they didn’t get skin cancer.
What was different? Well, their skin was different because they weren’t spending all day inside, and I think the indoor lifestyle, broken by things like occasional vacations in Ibiza, is probably the pattern that that’s trouble.
It’s skin that isn’t prepared for sunlight, because it’s indoors all the time, and then it’s suddenly getting shocked by something and is completely unprepared to deal with it. The big problem, from the data I’ve seen, comes from intense sun exposure, like frying yourself on the beach—there’s clearly no advantage to that.
Farmers don’t tend to have high rates of skin cancer, because they get chronic daily exposure. Those people have lower rates of melanoma than office workers. The people who have the highest rates of melanoma are people who get intermittent burns.
How to Make Sense of That “Rise of Skin Cancer and Rise of Sunscreen Use” Thing
THAT FIRST WAVE of sun products—they weren’t even sunscreens, they were sun tanning lotions. So they were supposed to help you tan, and the way they did that is they blocked UVB, which is what triggers sunburns. They did not block UVA, and at the time people didn’t think it was a problem; they didn’t think UVA caused cancer. In fact, old studies often showed that sunscreen users actually had higher rates of skin cancer than non-users. and I think probably it was because they were only blocking UVB.
So everyone in my generation grew up using those sunscreens and not burning, but thinking we’re safe on the beach. But we were just absorbing vast amounts of UVA. UVA causes free radicals, and the generation of free radicals turns out to be probably a bigger cause of skin cancer. So by the 90s, the message was, holy cow, we really have to cover the UVA too. So then we got broad-spectrum sunscreens, and there shouldn’t be any sunscreens on the market that aren’t broad spectrum. Sunscreen does have chemicals in it and it’s absorbed into the body at higher levels than we used to be told. But there’s no sign that it’s bad.
Tanning Beds Aren’t an Answer
TANNING BEDS ARE bad news—they’re associated with melanoma pretty clearly. There are a lot of UVA rays, so you think you’re safe because you’re not burning. But when you’re getting natural sunlight, you’re getting a mix of different photons, as humans have for years. It seems that if you chop that up and are only getting certain ones of those rays, no human being ever experienced that before the invention of all these artificial lights. The body doesn’t quite know what to do with that, and it seems like that’s where the trouble starts.
The Health Benefits of Sunlight Weren’t Just Suddenly Discovered
I KIND OF thought when I started doing my research that science has just discovered all of this. But throughout many decades, little bits of this information would come to light in studies, a few stories would be written, and then it would never take off. Scientists don’t have a whole lot of say about what gets beyond their labs and into the public consciousness—it has more to do with whatever entities exist to help amplify their message or study. So the most important ones don’t always get amplified—it’s the ones where there’s some funding to amplify it.
But there’s also this thing in psychology called the anchoring bias, where whatever we learn first we tend to hold onto unless the evidence otherwise is overwhelming. I think we’ve got this anchoring bias, where what we all learned and had really driven into us was that sunlight was dangerous, causes skin cancer, and the authorities invested a huge amount of time and energy and reputation in driving that message home to try to reduce rates of skin cancer, so then there’s just like a sort of built-in subconscious resistance to having to complicate the story.
How Much Sunlight You Should Get
THE RECOMMENDATIONS IN my book are in a sense super boring: Get sun. Not too much. Go outside.
Really, How Much Sunlight You Should Get
THERE’S NO SINGLE prescription: It depends on who you are and where you live and what time of year it is. I think the problem is less about sun exposure and more about sun deficiency. You don’t need too much; you just need to stay out of that sun-deficient zone. It’s tough to say exactly what that is, but you can kind of use Vitamin D as a proxy, because it’s a good measure of how much sunlight you’ve been getting. To get it to the sweet spot level of about 25 ng/ml, a fair-skinned person in summer might need 10 to 15 minutes of exposure, maybe double that if you have olive skin, and if you have truly dark skin, you can probably get as much as you want.
There’s one group that needs to be very careful about sun exposure. It’s well established in the dermatology literature that melanoma rates are much higher in people with fair skin, especially if they have red hair and have a lot of moles. They react completely differently to sunlight than everyone else.
What to Do in Winter
YOU CAN STILL get other benefits of sunlight. The infrared part of the solar spectrum, which is about 50 percent of sunlight, seems to have significant health benefits, especially for the mitochondria. Inflammation is related to mitochondria. Diseases of aging like cardiovascular disease, cancer, Alzheimer’s disease point to inflammation and inflammation gets explained as your immune system going nuts. But the reason your immune system is going nuts is looking more and more like it’s reacting to mitochondria that are basically sputtering. To get infrared light, you just need to be outside to get it; our indoor lighting doesn’t produce it at all. It goes right through clothing and hits every cell in your body. This part of the spectrum seems to be quite good for you—that’s why we’re seeing all these red light therapy clinics and why dermatologists have red light therapy options now.
Whether Sunlight Tracking Apps Help
THE APPS COULD be helpful as far as gathering information, but I wonder if they could also trip you up. I think getting sunlight should be uncomplicated. You don’t need an app for this; you just need to not hide in a cave.
Marty Munson, currently the health director of Men’s Health, has been a health editor at properties including Marie Claire, Prevention, Shape and RealAge. She’s also certified as a swim and triathlon coach.
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