Deep Dive

SUNLIGHT

Sunlight is healthy. It regulates our circadian rhythm and it helps our body produce vitamin D. But that’s far from the whole story. In fact, we may not truly understand even those things yet.

Creatures living on earth have a number of natural inputs. The foods they eat, the water they drink and the air they breathe. And the sun that shines on them. The sun has been a constant factor in the evolution of life, and it should come as no surprise that it plays a central role in many biological processes. Not only in plants, but also in animals and humans.

Vitamin D

We produce vitamin D under the influence of sunlight on our skins. Vitamin D is extremely important, and people with lower levels of vitamin D have significantly higher rates of almost every possible disease: cancer, diabetes, obesity, osteoporosis, heart attack, stroke, depression, autoimmune conditions and more. Moreover, vitamin D is necessary for your bones to absorb calcium making it essential for healthy bones. It’s no wonder a huge market for vitamin D supplements has sprung up to help us get our vitamin D fix even when we spend most of our day indoors.

But something doesn’t quite fit. Research upon research investigating the effect of vitamin D supplements has found the same results: vitamin D supplements have zero impact on cancer, heart disease or stroke. Recently, some scientists have suggested that maybe not all the benefits we get from the sun are from vitamin D itself. Maybe the sun has other effects on us, and vitamin D is only a marker for these effects because both correlate to sun exposure. One such substance they found was nitrous oxide. People that spent 30 minutes in the summer sun produced more nitrous oxide which lowered their blood pressure. A lower blood pressure is associated with lower incidence of heart disease and stroke.

It is likely that the sun fuels other, as yet undiscovered mechanisms that benefit our health. Benefits that are difficult if not impossible to copy with supplements. Clearly, if we want to improve our health, we should go out into the sun more often. But wait, didn’t exposure to the sun cause cancer? How do you spend 30 minutes in the sun without accidentally contracting skin cancer?

Skin cancer

Exposure to the sun increases a person’s chance of contracting melanoma, a potentially deadly form of skin cancer. This has led dermatologists to advise us that it’s best to wear SPF 30 or higher whenever we venture outside. It’s safer to not take the risk and use pills to supplement vitamin D, they reason. But if pills are as ineffective as the research suggests, it could be time to reevaluate this advice.

The chance of skin cancer is small
Skin cancer is not particularly prevalent. In the U.S., it causes less than 3 deaths per 100,000 inhabitants each year. For every person that dies of skin cancer, more than 100 die from cardiovascular diseases. Could it be that our fear for a relatively obscure cancer is actually increasing our risk of dying from other, far more common diseases?

The sun also protects us
In a particularly noteworthy study tracking the sunbathing habits of 30,000 Swedish women over 20 years, a few interesting things were discovered. It was indeed found that sun worshippers had a higher incidence of melanoma. But they were 8 times less likely to die from them. Even more shockingly, over the 20 years of the study, sun avoiders were twice as likely to die (from any cause) as sun worshippers. That’s huge. Short of giving up smoking or Nascar racing, there are very few habits you could adopt that halve your chances of dying. And certainly none as simple as exposing yourself to some daily sunlight.

Exercise your sun exposure
You can further reduce your risk of melanoma if you exercise your skin a little every day. If you sit still all year and then attempt to run a marathon, you will run a severe risk of injuries, overfatigue and even heart failure. But somehow we think it’s completely normal to sit inside all year and then go to the beach for a 6 hour sunbathing session. The result? Sunburn and a high risk of melanoma. If you “train” your skin, i.e. build up your sun exposure gradually, the melanin you produce as you tan will eventually protect you from melanoma naturally. And as a bonus you’ll look great.

So what does all this mean?

It means that going out into the sun, especially in spring and summertime, has a big positive impact on your health. This is true for anybody, but especially if you have naturally darker skin. Preferably, you go out without sunscreen and you put on a shirt when your skin starts to feel hot. Sunburn is not just a nuisance, it’s also a signal your body gives you to get into the shade. Ironically, sunscreen may unintentionally throw this signalling mechanism off balance. You won’t get burned so you stay out in the sun longer than you should, with a potentially increased skin cancer risk as a result (sunscreen is not 100% effective at absorbing the UVA rays causing skin cancer).

We advise against all-day sunbathing as a hobby. If you know you have to be in the sun for a long time, high SPF sunscreen is probably still your best option. But if you just want to spend some time at the beach, bring some light coloured summer clothes and a broad-rimmed hat and put them on whenever you’re not swimming.