Endocrine Abstracts

JOINT2160

Background: Thyroid health depends on sufficient iodine nutrition, which conversely relies on dietary habits. Dairy products, tap water, and marine foods are potential sources of iodine and may contribute to the iodine intake. In the Faroe Islands, dietary habits shift from the traditional diet dominated by iodine-rich marine foods. We investigated potential sources of iodine and their relation to iodine nutrition among populations in the Faroe Islands.

Methods: We collected a variety of Faroese foods and tap water and conducted three cross-sectional studies between 2000 and 2020 to include adolescents, adults, and pregnant women. Participants were randomly selected to ensure a representative sample of the Faroe Islands. Participants filled in a questionnaire on demographic and iodine-related determinants. A spot urine sample was collected for iodine determination using the Sandell-Kolthoff reaction modified according to Wilson and van Zyl.

Results: Marine foods and seabirds had iodine contents ranging from 300 µg/kg. Lamb meat iodine content varied by 100%, depending on whether it was herded on an island with beaches (105 µg/kg) or cliffs (53 µg/kg) facing the ocean. Tap water iodine content was <2 μg/l. We estimated the iodine intake from four scenarios of Faroese meals, and it varied from 50 µg to just over 200 µg with diets rich in marine foods. The three studies covered the age span from 14 through 74 years without overlapping. The study of adolescents included 129 participants, and the median urinary iodine concentration (UIC) in this group was 166 μg/l. The study of pregnant women included 647 participants with an average age of 30 years and a median UIC of 110 μg/l when assessed in median pregnancy week 18. In the study of adults aged 40 through 74, the 491 participants had a median UIC of 101 μg/l. Diet impacted UIC with a dependency on fish and whale meals, while dairy products were not a source of iodine among Faroese.

Conclusion: Faroese marine foods were iodine-rich, and the populations included reported the intake of these foods. UIC in sub-populations in the Faroe Islands showed a dependency on marine meals, while dairy products had little influence on UIC.