According to Lifehacker, new studies show that we aren't getting enough Vitamin D, due to sun block. One scientist said, "We are the first society of cave people," he lamented to me in 2010. "In the development process of creating the skin, nature never dreamed that we'd deliberately avoid the Sun so thoroughly."
Without Vitamin D, we can develop terrible diseases. Tumors can spread quicker. There are even a few that say that it can lead to autism (but I'm not at all convinced).
Still, I think the main finding of the research – we are Vitamin D deficient – is a serious concern. Go outside and garden for twenty minutes today. If I can't get a bad sunburn in 20 minutes, then you're all fine.
Apt. 11d 
Well, I can get a bad sunburn in 20 minutes. 🙂 But I can make it 10, which may be enough. (I was out walking the dog after dark the other night and realized I’d forgotten my headlamp, which I basically use so people can see me. Then I realized my blindingly white legs would be enough. 😉
My physician added a vitamin D check to my bloodwork last time and found me deficient. I’m supposed to take vitamin D but the pill is big and doesn’t fit into my pillbox with my 40-year-old-woman cocktail (meds for rosacea, anxiety, and HBP). So I’ll just risk a burn and go out daily for 10 minutes at least sans sunblock. Any more time outdoors, and on goes the sunblock.
I found the autism speculation intriguing, even though I am pretty sure autism has a strong genetic component.
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I currently have a hand print sunburn from haphazzard sun screen application.
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I don’t burn nowadays (tfoo-tfoo) but I faithfully wear a hat outdoors and spray my arms. I wear sandals half the year, though, and the tops of my feet are invariably mahogany by the end of the summer (with white stripes where the straps were).
I often don’t bother with sunblock and hats for the kids unless they’re going to be outside for a while. Interestingly, in our sunny climate, the kids can start freckling up just from the exposure they get while walking across a parking lot. I prefer those Landsend swimsuits with sleeves and shorts for the kids for outdoor pools, because it’s just too easy to miss spots around the shoulder straps.
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I’m with you on the rash guards, Amy. It makes sunscreen application so much easier.
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I can burn in well under 20 minutes too! As a kid people used to ask my parents if I was albino. Now I’m a bit darker, but not by much. I’ve found a great way to get sun and not get horribly burned is to go out in the early evening, around 5 pm. I still get sun (and the freckles to prove it) but I don’t get horrible burns. I do try to go out and about without sunscreen during the day, so hopefully the 10 minute walk to the library helps. I remember asking my doctor about this, and she said that the amount of exposure needed really does depend on skin color. People on the very pale end need really only about 10 mins a day, and should worry more about skin cancer. On the other end, she said dark skinned African Americans really should aim for around an hour a day. Many of her patients are elderly black people who don’t get out much, and she said vitamin D deficiency is a huge problem in that community. It would be interesting to see to what extent vitamin D deficiency contributes to racial health disparities in the US.
Also, I wonder if Vitamin D problems also relate to people drinking less milk? We should be able to get enough vitamin D between milk + some outdoor exposure. horribly, thus allowing yourself to get vitamin D.
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Oh, also, I agree with the main point–people should make sure they’re not vitamin D deficient–but there’s some seriously flawed science going on. Unless new findings have come out in the past 3 years, there’s no evidence light skin developed under pressures of natural selection. Darker skinned people are at higher risk of rickets, but not enough so to impact ability to reproduce, and given the lifestyle of early humans, even dark skinned people would get enough sun exposure at northern latitudes. Secondly, indigenous people in the far north aren’t particularly pale (Inuits, native Siberians, Greenlanders, Sami) generally have darker skin and hair. They get lots of vitamin D through consumption of animal meats like seal and reindeer, which are high in vitamin D. The light skin of the Europeans (particularly the Germanic tribes that took over northern Europe) was more likely due to genetic drift or the result of gene fixing through inbreeding in a small population and/or sexual selection, and indeed they were latecomers to the northern regions of the world. I read a paper from maybe 2007(?) showing that light skin in Ireland and Sweden arises from at least 17 separate mutations, showing very little selection pressure. In contrast, dark skin in equatorial Africa is the result of one gene, indicating extremely high selection pressure on dark skin in sunny climates.
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“It would be interesting to see to what extent vitamin D deficiency contributes to racial health disparities in the US.
Also, I wonder if Vitamin D problems also relate to people drinking less milk? We should be able to get enough vitamin D between milk + some outdoor exposure. horribly, thus allowing yourself to get vitamin D.”
Don’t forget that a lot of non-Caucasians are lactose intolerant, so they’d naturally steer away from a lot of the traditional vitamin-D enriched foods.
There’s an additional issue here with regard to lead poisoning. I think I’ve read that children with good mineral intake have some protection from environmental lead (paint, etc.). So, not being able to freely eat dairy (the easy way to pick up calcium, etc.) would make children more susceptible to lead poisoning.
YMMV depending on geographical location in the US. I think you’d literally have to be a cave-dweller to not get enough sun in Texas, regardless of skin tone.
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Darker skinned people are at higher risk of rickets, but not enough so to impact ability to reproduce
It doesn’t seem possible for both of those to be right.
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MH,
It’s a matter of probabilities and impact to reproductive fitness and all other factors being held the same. If (I’m making up these numbers) light skinned people need 200 units of vit D, and very dark skinned people need 500 units, but through sun exposure they are both getting 800 units, than the relatively higher risk for dark skinned people will not impact fitness. Conversely, if light skinned people get 200 units through sun exposure, and darker skinned people get 200 units through sun and 300 units through seal meat, then they have successfully adapted to their environment and reproductive fitness is not affected. Of course, if seal hunting is banned and these people are forced to survive off of spam, darker skin becomes more of a problem. Or if, say, a dark skinned person who would be fine as an agricultural laborer in England suddenly spends 16 hours a day in a work house, rickets would be a comparatively bigger problem for that person than for a light skinned person. Of course, the major structural changes which keep everyone inside all day are too recent to affect skin color evolution, and previously people’s lifestyles and diets neutralized any disadvantages darker skin had, meaning there was little selective pressure for light skin. If currently we’re seeing Vitamin D deficient driven selective pressure for light skin, and skin cancer driven selective for dark skin, it will be interesting to see what happens. (Probably nothing, because both light and dark skinned people have ways to mitigate damages caused by these problems)
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O.K. But saying dark skin gives you a higher risk for rickets that doesn’t affect your reproductive ability if you can compensate for it so that you aren’t actually at a higher risk of getting rickets is very different from saying dark skin increases your risk for rickets without hurting your reproductive ability.
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I had been suffering from some chronic pain issues–joints, muscle pain, fatigue. I found out I am Vitamin D deficient. So is my husband. We live in the sunny southwestern U.S. Generally, I walk at least 20 minutes a day getting to and from work, plus I generally walk outside another three times a week for 45-60 minutes. My husband spends even more time outside. I am fair-skinned and pretty lazy about sunscreen. We definitely should be making enough Vitamin D through sun exposure–but I am wondering if there’s some other process interfering with Vitamin D production or uptake. I started taking 4000 IU of Vitamin D daily and my symptoms are now almost completely gone.
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Speaking of sunlight, some people get an autoimmune response to it. One of my outdoorsy relatives developed the condition in middle age.
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