I don’t think hunter-gatherers get 16000 to 32000 IU of Vitamin D daily. This study suggests Hadza hunter-gatherers get more like 2000. I think the difference between their calculation and yours is that they find that hunter-gatherers avoid the sun during the hottest part of the day. It might also have to do with them being black, I’m not sure.
Hadza hunter gatherers have serum D levels of about 44 ng/ml. Based on this paper, I think you would need total vitamin D (diet + sunlight + supplements) of about 4400 IU/day to get that amount. If you start off as a mildly deficient American (15 ng/ml), you’d need an extra 2900 IU/day; if you start out as an average white American (30 ng/ml), you’d need an extra 1400 IU/day. The Hadza are probably an overestimate of what you need since they’re right on the equator—hunter-gatherers in eg Europe probably did fine too. I think this justifies the doses of 400 − 2000 IU/day in studies as reasonably evolutionarily-informed.
Please don’t actually take 16000 IU/day of vitamin D daily, if taken long-term this would put you at risk for vitamin D toxicity.
I also agree with the issues about the individual studies which other people have brought up.
Thanks, the Hadza study looks interesting. I’d have to read carefully at length to have a strong opinion on it but it seems like a good way to estimate the long-run target. I agree 16,000 is probably too much to take chronically, I’ve been staying below the TUL of 10,000, and expect to reduce the dosage significantly now that it’s been a few years and COVID case rates are waning.
I don’t think hunter-gatherers get 16000 to 32000 IU of Vitamin D daily. This study suggests Hadza hunter-gatherers get more like 2000. I think the difference between their calculation and yours is that they find that hunter-gatherers avoid the sun during the hottest part of the day. It might also have to do with them being black, I’m not sure.
Hadza hunter gatherers have serum D levels of about 44 ng/ml. Based on this paper, I think you would need total vitamin D (diet + sunlight + supplements) of about 4400 IU/day to get that amount. If you start off as a mildly deficient American (15 ng/ml), you’d need an extra 2900 IU/day; if you start out as an average white American (30 ng/ml), you’d need an extra 1400 IU/day. The Hadza are probably an overestimate of what you need since they’re right on the equator—hunter-gatherers in eg Europe probably did fine too. I think this justifies the doses of 400 − 2000 IU/day in studies as reasonably evolutionarily-informed.
Please don’t actually take 16000 IU/day of vitamin D daily, if taken long-term this would put you at risk for vitamin D toxicity.
I also agree with the issues about the individual studies which other people have brought up.
Thanks, the Hadza study looks interesting. I’d have to read carefully at length to have a strong opinion on it but it seems like a good way to estimate the long-run target. I agree 16,000 is probably too much to take chronically, I’ve been staying below the TUL of 10,000, and expect to reduce the dosage significantly now that it’s been a few years and COVID case rates are waning.