The Sun Exposure Dilemma

Yesterday, we asked you about your policy on sun exposure, and got the above-pictured, below-described, set of answers:

• A little over a third of respondents chose “I recognize the risks, but I think the benefits outweigh them”
• A quarter of respondentschose “I am a creature of the shadows and I avoid the sun at all costs‍♀️”
• A little over a fifth of respondents chose “I recognize the benefits, but I think the risks outweigh them”
• A little under a fifth of respondents chose “I’m a sun-lover! Give me that vitamin D and other benefits!”

All in all, this is perhaps the most even spread of answers we’ve had for Friday mythbuster polls—though the sample size was smaller than it often is.

Of those who added comments, common themes were to mention your local climate, and the importance of sunscreen and/or taking vitamin D supplements.

One subscriber mentioned having lupus and living in Florida, which is a particularly unfortunate combination:

Lupus Foundation | Lupus & UV exposure: What you need to know

Another subscriber wrote:

❝Use a very good sunscreen with a high SPF all the time. Reapply after swimming or as needed! I also wear polarized sunglasses anytime I’m outside.❞

…which are important things to note too, and a lot of people forget!

See also: Who Screens The Sunscreens? (on fearing chemical dangers, vs the protection given)

But, onto today’s science for the topic at hand…

We need to get plenty of sun to get plenty of vitamin D: True or False?

True or False, depending on so many factors—to the point that many people get it wildly wrong in either direction.

Whether we are getting enough vitamin D depends on many circumstances, including:

• The climate (and depending on latitude, time of year) where we live
• Our genes, and especially (but not only) our skintone
• The clothes we wear (or don’t)
• Our diet (and not just “how much vitamin D do we consume”)
• Chronic diseases that affect vitamin D metabolism and/or requirements and/or sensitivity to the sun

For a rundown on these factors and more, check out:

Should I be getting my vitamin D levels checked?

Notably, on the topic of whether you should stay in the sun for longer to get more vitamin D…

❝The body can only produce a certain amount of vitamin D at the time, so staying in the sun any longer than needed (which could be just a few minutes, in a sunny climate) is not going to help increase your vitamin D levels, while it will increase your risk of skin cancer.❞

Source: Dr. Elina Hypponen, professor of Nutritional Epidemiology, and director of the Australian Centre for Precision Health at the University of South Australia Cancer Research Institute.

In contrast, she does also note:

❝During winter, catching enough sun can be difficult, especially if you spend your days confined indoors. Typically, the required exposure increases to two to three hours per week in winter. This is because sunlight exposure can only help produce vitamin D if the UVB rays reach us at the correct angle. So in winter we should regularly spend time outside in the middle of the day to get our dose of vitamin D.❞

See also: Vitamin D & Calcium: Too Much Of A Good Thing?

We can skip the sun and get our vitamin D from diet/supplements: True or False?

True! However, vitamin D is not the only health benefit of sun exposure.

Not only is sunlight-induced serotonin production important for many things ranging from mood to circadian rhythm (which in turn affects many other aspects of health), but also…

While too much sun can cause skin cancer, too little sun could cause other kinds of cancer:

Benefits of Sunlight: A Bright Spot for Human Health

Additionally, according to new research, the circadian rhythm benefits we mentioned above may also have an impact on type 2 diabetes:

Can catching some rays help you fight off type 2 diabetes?

Which way to jump?

A lot of it depends on who you are, ranging from the factors we mentioned earlier, to even such things as “having many moles” or “having blonde hair”.

This latter item, blonde hair, is a dual thing: it’s a matter of genetic factors that align with being prone to being more sensitive to the sun, as well as being a lesser physical barrier to the sun’s rays than dark hair (that can block some UV rays).

So for example, if two people have comparably gray hair now, but one of them used to have dark hair and the other blonde, there will still be a difference in how they suffer damage, or don’t—and yes, even if their skin is visually of the same approximate skintone.

You probably already know for yourself whether you are more likely to burn or tan in the sun, and the former group are less resistant to the sun’s damage… But the latter group are more likely to spend longer in the sun, and accumulate more damage that way.

If you’d like a very comprehensive downloadable, here are the guidelines issued by the UK’s National Institute for Health and Care Excellence:

NICE Guidelines | Sunlight exposure: risks and benefits

…and skip to “At risk groups”, if you don’t want to read the whole thing; “Skin type” is also an important subsection.

Writer’s note: genetics are complicated and not everyone will fall neatly into categories, which is why it’s important to know the individual factors.

For example, I am light-skinned with slightly greying dark hair and blue-grey eyes, and/but also have an obscure Sámi gene that means my fair skin makes vitamin D easily, while simultaneously being unusually resistant to burning (I just tan).

And yet! My hobbies include not getting skin cancer, so I tend to still be quite mindful of UV levels in different weathers and times of day, and make choices (schedule, clothing, sunscreen or not) accordingly.

Bottom line:

That big self-perpetuating nuclear explosion in the sky is responsible for many things, good and bad for our health, so be aware of your own risk factors, especially for vitamin D deficiency, and skin cancer.

• If you have a predisposition to both, that’s unfortunate, but diet and supplementation at least can help with the vitamin D while getting modest amounts of sun at most.
• Remember that you can only make so much vitamin D at once, so sunbathing for health benefits need only take a few minutes
• Remember that sunlight is important for our circadian rhythm, which is important for many things.
• That’s governed by specific photoreceptor cells, though, so we don’t need our skin to be exposed for that; we just need to be able to see sunlight.
• If you’re going to be out in the sun, and not covered up, sunscreen is your friend, and yes, that goes for clear cold days under the winter sun too.
• Most phone weather apps these days have a UV index score as part of the data they give. Get used to checking it as often as you’d check for rain.

Stay safe, both ways around!