Iodine intake and status in two groups of Norwegians

Abstract

Objective: To evaluate the ranges of iodine intake and iodine status in two subgroups of the Norwegian population. Design: The participants in the Tromsø group (n = 63) had a normal diet. The participants in the Bergen group (n = 44) comprised people with a variable intake of fish and dairy products. Results: The iodine intake varied from 56 to 318 μg day -1 in the Tromsø group and from 30 to 427 μg day -1 in the Bergen group. Median intake of iodine (162 μg day -1) in the Tromsø group was significantly higher than in the Bergen group (89 μg day-1) (p < 0.001). Urinary iodine concentration varied from 38 to 572 μg 1-1 with a median value of 117 μg 1-1 in the Tromsø group. Median iodine excretion in the Bergen group was 96 μg 24 h-1 (85 μg 1-1) and varied from 16 to 316 μg 24 h-1. Median serum thyroid-stimulating hormone was 1.6 mIU 1-1 in the Tromsø group and 1.4 mIU 1 -1 in the Bergen group. Median free thyroxine in serum was significantly higher in the participants from Tromsø (15 pmol 1 -1) than in those from Bergen (12 pmol 1-1). Conclusions: Regular intake of dairy products and/or fish products is important to meet the iodine requirements in the Norwegian diet. Although the iodine intake was found to be in the intake range of sufficient iodine intake of most of the participants in the two groups, there may exist population groups with a very low average intake of iodine.