Nat Clin Pract Rheumatol. 2009 Feb;5(2):99-105. doi: 10.1038/ncprheum0989.
The effect of melanism and vitamin D synthesis on the incidence of autoimmune
disease.
Shoenfeld N(1), Amital H, Shoenfeld Y.
Author information:
(1)Be'er Ya'akov Mental Health Center, Be'er Ya'akov, Israel.
Melanin has several physiological roles in maintaining health, but, notably, it
affects the synthesis of vitamin D. Melanin is the primary determinant of the
degree of skin pigmentation and protects the body from harmful ultraviolet
radiation. Synthesis of 1,25-dihydroxyvitamin D(3) (1,25[OH](2)D(3)) in the skin,
however, is dependent on ultraviolet B light. Highly pigmented skin, to the level
found in people of African origin, abrogates almost all ultraviolet-induced
1,25(OH)(2)D(3) synthesis. Numerous animal models and clinical studies have
underlined the essential role of vitamin D as a modulator of the different
processes of the immune system. Evidence indicates that serum concentrations of
1,25(OH)(2)D(3) and the prevalence of autoimmune diseases in a certain population
are associated with the latitude at which that population resides. This article
explores the relationship between skin pigmentation, vitamin D and the prevalence
of autoimmune disease.
http://www.ncbi.nlm.nih.gov/pubmed/19182816