Just a small heads up - since Razib raised this very interesting subject and noted his own Vitamin D deficiency, I have been surprised by how prevalent it seems to be, even among pale-faces in regions where you'd expect ample access to UV. I guess people just don't spend the amount of time outdoors that they used to.
But apropos John Emerson's timely caution about moderation in supplement intake, it could also not be difficult to inadvertently OD. A lot of protein supplements have a sizeable addition of Vitamin D. If someone is using a lot of protein supplements and also taking Vitamin D supplements as cod liver oil capsules or whatever, then getting more than the maximum recommended daily dose would not be too difficult. It would pay to count the daily IU intake reasonably conscientiously.
Re: pale-faces with vitamin D deficiency, iirc they have that in Australia, where there was a mass panic about sunburn and skin cancer, so people avoided sun exposure.
Aggers - yes, spot on. Someone was even suggesting recently that the mass public education about avoidance of exposure to UV in Australia has had a net negative benefit in terms of mortality due to increase in Vitamin D deficiency in the whole population, i.e. most skin cancers are treatable and not fatal.
Of course there's a happy medium between total UV avoidance and lying on the beach in the sun for 4-5 hours a day, but the average dumb human doesn't seem too good at understanding 'happy medium'. But the public education campaigns did tend to make UV out to be toxic - overkill.
But this map: http://www.gnxp.com/blog/2007/09/uv-skin-color.php is very highly informative - in southern Australia it is really easy for pale skinned people to be over-exposed to UV in summer if they are reasonably active outdoors, but it's hard to get adequate UV exposure in mid-winter. But because Vitamin D deficiency in the population has tended to be underestimated in the past, there tends not to be Vitamin D fortification of milk etc. and little to no public education about it.
I was born in the most inland county in Ireland, where most people don't eat fish at all. I was diagnosed with ricketts at birth, and 3 of my Dad's 6 siblings have dies as a result of Colon Cancer - I guess the Irish are not pale enough...
Conroy - I can sympathize, having had surgery for colon cancer 2 years ago. I have no idea if a Vitamin D deficiency was implicated in my case.
I have a friend from the north of England who had ricketts as a child, I presume for the same reason. He's blonde, blue eyed and very fair skinned, but it evidently wasn't enough.
Of course he could just swallow a table spoon of Cod Liver Oil daily - or doesn't he like to swallow?!
Just a small heads up - since Razib raised this very interesting subject and noted his own Vitamin D deficiency, I have been surprised by how prevalent it seems to be, even among pale-faces in regions where you'd expect ample access to UV. I guess people just don't spend the amount of time outdoors that they used to.
But apropos John Emerson's timely caution about moderation in supplement intake, it could also not be difficult to inadvertently OD. A lot of protein supplements have a sizeable addition of Vitamin D. If someone is using a lot of protein supplements and also taking Vitamin D supplements as cod liver oil capsules or whatever, then getting more than the maximum recommended daily dose would not be too difficult. It would pay to count the daily IU intake reasonably conscientiously.
Re: pale-faces with vitamin D deficiency, iirc they have that in Australia, where there was a mass panic about sunburn and skin cancer, so people avoided sun exposure.
Aggers - yes, spot on. Someone was even suggesting recently that the mass public education about avoidance of exposure to UV in Australia has had a net negative benefit in terms of mortality due to increase in Vitamin D deficiency in the whole population, i.e. most skin cancers are treatable and not fatal.
Of course there's a happy medium between total UV avoidance and lying on the beach in the sun for 4-5 hours a day, but the average dumb human doesn't seem too good at understanding 'happy medium'. But the public education campaigns did tend to make UV out to be toxic - overkill.
But this map: http://www.gnxp.com/blog/2007/09/uv-skin-color.php is very highly informative - in southern Australia it is really easy for pale skinned people to be over-exposed to UV in summer if they are reasonably active outdoors, but it's hard to get adequate UV exposure in mid-winter. But because Vitamin D deficiency in the population has tended to be underestimated in the past, there tends not to be Vitamin D fortification of milk etc. and little to no public education about it.
Sanfgroper,
I was born in the most inland county in Ireland, where most people don't eat fish at all. I was diagnosed with ricketts at birth, and 3 of my Dad's 6 siblings have dies as a result of Colon Cancer - I guess the Irish are not pale enough...
Conroy - I can sympathize, having had surgery for colon cancer 2 years ago. I have no idea if a Vitamin D deficiency was implicated in my case.
I have a friend from the north of England who had ricketts as a child, I presume for the same reason. He's blonde, blue eyed and very fair skinned, but it evidently wasn't enough.