An evaluation of the relative contributions of exposure to sunlight and of diet to the circulating concentrations of 25-hydroxyvitamin D in an elderly nursing home population in Boston.
Webb AR, Pilbeam C, Hanafin N, Holick MF.
Am J Clin Nutr. 1990 Jun;51(6):1075-81.
PMID: 2349922
Sunlight regulates the cutaneous production of vitamin D3 by causing its photodegradation.
Webb AR, DeCosta BR, Holick MF.
J Clin Endocrinol Metab. 1989 May;68(5):882-7.
PMID: 2541158
doi:10.1210/jcem-68-5-882
Vitamin D3 proved to be exquisitely sensitive to sunlight, and once formed in the skin, exposure to sunlight resulted in its rapid photodegradation to a variety of photoproducts, including 5,6-transvitamin D3, suprasterol I, and suprasterol II.suprasterol I, and suprasterol II.
nfluence of season and latitude on the cutaneous synthesis of vitamin D3: exposure to winter sunlight in Boston and Edmonton will not promote vitamin D3 synthesis in human skin.
Webb AR, Kline L, Holick MF.
J Clin Endocrinol Metab. 1988 Aug;67(2):373-8.
PMID: 2839537
doi:10.1210/jcem-67-2-373
These results quantify the dramatic influence of changes in solar UVB radiation on cutaneous vitamin D3 synthesis and indicate the latitudinal increase in the length of the "vitamin D winter" during which dietary supplementation of the vitamin may be advisable.
Ultraviolet exposure scenarios: risks of erythema from recommendations on cutaneous vitamin D synthesis.
Webb AR, Engelsen O.
Adv Exp Med Biol. 2008;624:72-85.
PMID: 18348448
DOI: 10.1007/978-0-387-77574-6_6