Invited commentary in response to: Serum 25-hydroxyvitamin D, calcium and parathyroid hormone in Native and European populations in Greenland

Abstract

Inuit populations in nutrition transition are at risk of compromised nutritional status Inuit populations in the Arctic are undergoing nutrition transition and there are concerns that a shift from the traditional diet, rich in seal, whale, wild fowl, reindeer, musk ox and hare, towards an imported, highly processed diet, is compromising food security and nutritional status by undermining a core component of the Inuit adaptation to life in the Arctic. Using data from the International Polar Year Inuit Health Survey (2007-2008) of thirty-six Inuit communities in Northern Canada, Egeland et al. (1) reported higher intakes of protein and micronutrients among traditional food consumers and higher carbohydrate, saturated fat, dietary fibre and Na:K intakes among non-consumers. Several nutritional biomarkers, including serum concentrations of 25-hydroxyvitamin D (25(OH)D), indicating vitamin D exposure, were higher among traditional food consumers. Older adults consumed more traditional foods and had higher vitamin D intakes than younger adults. Among 2207 individuals (2) , more than 40 % overall had low vitamin D status, indicated by having a 25(OH)D concentration below 50 nmol/lthe target specified by the Institutes of Medicine (3) , the European Food Safety Authority (4) and Norden (5) to meet the vitamin D requirements of almost all healthy persons. The strongest determinants of 25(OH)D were older age and healthy waist circumference (2). The Inuit Health in Transition study in West and East Greenland, conducted from 2005 to 2010, told a similar story. Among 2877 randomly selected Inuit adults, Nielsen et al. (6) reported that serum 25(OH)D concentrations were lowest among 18-29-year-olds, at approximately 31 nmol/l, and increased with age. The other important determinants of vitamin D status were consumption of a traditional diet and female sex. This study analysed bio-banked samples collected in 1987 from a subgroup of 330, allowing analysis of trends over time. Among all ages, 25(OH)D decreased by one-third to a half over the 30-year time frame. The authors suggested that a change away from a traditional diet may explain this decline (6) , although there were no dietary data to support this suggestion.