Vitamin D: in the evolution of human skin colour.
The natural selection hypothesis suggests that lighter skin colour evolved to optimise vitamin D production. Some authors question if vitamin D deficiency leads to sufficient health problems to act as a selection pressure. This paper reviews the numerous effects of vitamin D deficiency on human health and argues that vitamin D deficiency is sufficient to pose as a potent selection pressure for lighter skin colour. Vitamin D deficiency manifesting as rickets and osteomalacia are sufficient to impair reproductive success, but additionally, animal studies and some clinical observations suggest that vitamin D may have more direct impact on human fertility. Vitamin D deficiency may lead to a whole host of clinical conditions which impair health and increase mortality rates: increase susceptibility to bacterial and viral infections; rickets, osteomalacia and osteoporosis, with increased risk of falls and fractures; increased risk of cancers; hypertension and cardiovascular disease; maturity onset diabetes; autoimmune diseases such as multiple sclerosis, rheumatoid arthritis, inflammatory bowel disease and Type 1 diabetes; and gum disease. We submit that at higher latitudes, lighter skin colour evolved to facilitate vitamin D production under conditions of low ultra-violet B radiation in order to avoid a plethora of ill health, reproductive difficulties and early mortality.
Yuen
A W C
AW
Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK. alan@yuen.co.uk
Jablonski
N G
NG
D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D002986:Clinical Trials as Topic; D005260:Female; D005298:Fertility; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D008962:Models, Theoretical; D009369:Neoplasms / Q000378:metabolism* / Q000473:pathology; D012306:Risk; D012880:Skin Pigmentation; D014807:Vitamin D / Q000378:metabolism*; D014808:Vitamin D Deficiency / Q000150:complications* / Q000175:diagnosis*
D014807:Vitamin D