4. Discussion
As far as we are aware, this is the first systematic study in Spain
of the iodine concentration range in milk. The results show the
current composition of iodine in cow’s milk available on the
Spanish market. The comparison between the 1991 and present
samples suggests a significant increase in the milk iodine concentration
over this time period. Additionally, the results show that
cow’s milk is a relevant source of dietary iodine.
Several studies have shown that the dietary iodine concentration
has varied greatly over the years. In the USA, the concentration
of iodine in milk fell from 1975 to 1982, and remained relatively
stable from 1982 to 1990 with iodine concentrations around
230 mg/L and a CV of 39%.19 However, an area of Boston has been