To reach the circulating (25-hydroxy) vitamin D levels associated with the lowest overall mortality, one may need to take supplements, given data suggesting suboptimal production from sun even under optimal circumstances.
Image thanks to Tobyotter.
How much sun exposure might one need to get their target vitamin D level to that found associated with the lowest total mortality rate? Well, it depends. It depends on our age, how long we’re exposed, the time of day, the time of year, our latitude, our skin color, our use of sunscreen, and how much of our body we’re exposing. Even in Boston, though, all it takes is 10-12 minutes, of midday, summer sun, without sunblock—if, you’re a young, pale, naked caucasion. But then you’re golden! Actually, you’d be a little pink. Note, though, if you’re some old white guy prancing around naked on the Commons you’re not going to make it.
As I’m hope you’re beginning to appreciate, it’s not easy to make one-size fits all recommendations for how much sun exposure one might need. And “Low vitamin D status despite abundant sun exposure” has been found even in the best of circumstances: young, half naked skateboarders in Honolulu, mostly caucasion, averaging 30 hours of sun a week, and 51% didn’t even make it to 30. If they can’t, who can?
And these days, even if we’re an albino nudist at the equator, how often might we be getting outside in middle of the day with a deskjob?
So, if we’re really interested in getting to the vitamin D level associated with the lowest mortality rates, and our lifestyle or latitude won’t allow us the necessary sun exposure, then one needs to take vitamin D supplements: the piddly amount added to soymilk, calfmilk, margarine or mushrooms would simply not be enough.
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring watch the above video. This is just an approximation of the audio contributed by veganmontreal.
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Please feel free to post any ask-the-doctor type questions here in the comments section and I’d be happy to try to answer them. This is the fifth video in a nine day series on vitamin D. Be sure to check out yesterday's video-of-the-dayVitamin D and mortality may be a U-shaped curve.
Also, check out my associated blog posts for additional context: Eating To Extend Our Lifespan, Vitamin D: Shedding Some Light on the New Recommendations, and Vitamin D from Mushrooms, Sun, or Supplements?