Vitamin D deficiency among northern Native Peoples: a real or apparent problem?

• Published in: International Journal of Circumpolar Health
• Main Author: Peter Frost
• Format: Article in Journal/Newspaper
• Language: English
• Published: Taylor & Francis Group 2012
• Subjects: Inuit; North American Indians; rickets; vitamin D; vitamin D deficiency; population genetics; Arctic medicine. Tropical medicine; RC955-962; Arctic; Circumpolar Health; International Journal of Circumpolar Health; inuit
• Online Access: https://doi.org/10.3402/IJCH.v71i0.18001; https://doaj.org/article/0a2b02a9c64f430a8335577a8d85441d

Vitamin D deficiency seems to be common among northern Native peoples, notably Inuit and Amerindians. It has usually been attributed to: (1) higher latitudes that prevent vitamin D synthesis most of the year; (2) darker skin that blocks solar UVB; and (3) fewer dietary sources of vitamin D. Although vitamin D levels are clearly lower among northern Natives, it is less clear that these lower levels indicate a deficiency. The above factors predate European contact, yet pre-Columbian skeletons show few signs of rickets—the most visible sign of vitamin D deficiency. Furthermore, because northern Natives have long inhabited high latitudes, natural selection should have progressively reduced their vitamin D requirements. There is in fact evidence that the Inuit have compensated for decreased production of vitamin D through increased conversion to its most active form and through receptors that bind more effectively. Thus, when diagnosing vitamin D deficiency in these populations, we should not use norms that were originally developed for European-descended populations who produce this vitamin more easily and have adapted accordingly.