Could one design an effective sun block which passes the spectrum necessary for Vitamin D synthesis?
Vitamin D is most succesfully synthesized in the skin at wavelengths of 270-290nm, which is just outside of the UVA and UVB spectra. A sunblock that uses salicylic acid as the effective ingredient shouldnt block Vit D production.
Vitamin D production peaks at 297 nm, right in the middle of the UVB band (280 - 315 nm), suggesting that separation of Vitamin D metabolism from burning will be difficult or impossible.
EDIT: "..the ultraviolet action spectra for DNA damage, skin cancer, and vitamin D3 photosynthesis are identical ..."
B. Gilchrest, American Journal of Clinical Nutrition, Vol. 88, No. 2, 570S-577S, August 2008
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