I read his work years ago. My takeaways from his work and some supplementary reading were:
- Data are observational but pretty convincing, sufficiency lower all kinds of diseases. Striking was the much lower prevalence of all kinds of cancers in the sun belt.
- Dosage should be in the several 1000 IU range / day, no need to be concerned about toxicity in that range.
- Should be dosed often rather than megadoses once a fortnight because its metabolism is complex. So while the stored form is good for bone health, the effects against cancer and infections may rest on the early metabolites.
- Don't forget about Vitamin K2 when taking high doses.
- No chance to make Vit D from sun from October to March even at noon at Boston latitude (which is more like Rome for us Europeans)
- Best time is around noon because of better UV B to UV A ratio.
- This really turned my previous indoctrination on its head. Melanoma seems to be caused mainly by UV A, so all those sun screens that used to filter only UV-B well into the 90s got it wrong, and even today, UV-A filtering is usually lower than UV-B filtering.
- Holick also cites data from ~1900 California that office workers had much higher rates of melanoma than farm hands and construction workers. Probable reason: window glass filters UV B but only some UV A.
Edit: this is the paper on sunlight that contains much of the information I summarized above and is very much readable:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3897598/
- Data are observational but pretty convincing, sufficiency lower all kinds of diseases. Striking was the much lower prevalence of all kinds of cancers in the sun belt.
- Dosage should be in the several 1000 IU range / day, no need to be concerned about toxicity in that range.
- Should be dosed often rather than megadoses once a fortnight because its metabolism is complex. So while the stored form is good for bone health, the effects against cancer and infections may rest on the early metabolites.
- Don't forget about Vitamin K2 when taking high doses.
- No chance to make Vit D from sun from October to March even at noon at Boston latitude (which is more like Rome for us Europeans)
- Best time is around noon because of better UV B to UV A ratio.
- This really turned my previous indoctrination on its head. Melanoma seems to be caused mainly by UV A, so all those sun screens that used to filter only UV-B well into the 90s got it wrong, and even today, UV-A filtering is usually lower than UV-B filtering.
- Holick also cites data from ~1900 California that office workers had much higher rates of melanoma than farm hands and construction workers. Probable reason: window glass filters UV B but only some UV A.
Edit: this is the paper on sunlight that contains much of the information I summarized above and is very much readable:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3897598/
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