Iodine content in drinking water and other beverages in Denmark

Objective: To investigate the variation in iodine content in drinking water in Denmark and to determine the difference in iodine content between organic and non-organic milk. Further, to analyse the iodine content in other beverages. Design and setting: Tap water samples were collected from 41 evenly distributed localities in Denmark. Organic and non-organic milli was collected at the same time (twice summer and twice winter). Soft drinks, beers and juice were collected from different Danish producers and wine from different countries. All samples were analysed for iodine using inductively coupled mass spectrometry. Results: Iodine in tap water varied from 2.1 to 30.2 mu g/l; the iodine content was in general highest in the eastern part of Denmark and lowest in the western part of Denmark. Organic milk was found to have a lower iodine content than non-organic milk. Conclusions: Large geographical (and seasonal) variations in iodine concentrations were found in different beverages supplying an appreciable part of the iodine in the Danish diet. This knowledge is important when calculating the iodine intake from dietary intake studies.