Iodine concentration of milk-alternative drinks available in the UK in comparison to cows’ milk

Abstract

Iodine deficiency is present in certain groups of the UK population, notably in pregnant women; this is of concern as iodine is required for fetal brain development. UK milk is rich in iodine and is the principal dietary iodine source. UK sales of milk-alternative drinks are increasing but data are lacking on their iodine content. As consumers may replace iodine-rich milk with milk-alternative drinks, we aimed to measure the iodine concentration of those available in the UK. Using ICP-MS, we determined the iodine concentration of seven types of milk-alternative drink (soya, almond, coconut, oat, rice, hazelnut, and hemp) by analysing 47 products purchased in November/December 2015. For comparison, winter samples of conventional (n=5) and organic (n=5) cows’ milk were included. The median iodine concentration of all of the unfortified milk-alternative drinks (n=44) was low, at 7.3 μg/kg, just 1.7% of our value for winter conventional cows’ milk (median 438 μg/kg). One brand (not the market leader), fortified its soya, oat, and rice drinks with iodine and those drinks had a higher iodine concentration than unfortified drinks, at 280, 287, 266 μg/kg respectively. The iodine concentration of organic milk (median 324 μg/kg) was lower than that of conventional milk. Although many milk-alternative drinks are fortified with calcium, at the time of this study, just three of 47 drinks were fortified with iodine. Individuals who consume milk-alternative drinks that are not fortified with iodine in place of cows’ milk may be at risk of iodine deficiency unless they consume alternative dietary iodine sources.