Milk is the largest source of iodine in UK diets and an earlier study showed that organic summer milk had significantly lower iodineconcentration thanconventionalmilk. There are no comparable studies with wintermilk or the effect of milk fat class or heat processing method.
Two retail studies withwintermilk are reported.
Study 1 showed no effect of fat class but organicmilk was 32.2% lower in iodine than conventionalmilk (404 vs. 595 μg/L; P<0.001).
Study 2 found no difference between conventional and Channel Island milk but organicmilk contained 35.5% less iodine than conventionalmilk (474 vs. 306 μg/L; P<0.001). UHT and branded organicmilk also had lower iodine concentrations than conventionalmilk (331 μg/L; P The results indicate that replacement of conventionalmilk by organic or UHT milk will increase the risk of sub-optimal iodine status especially for pregnant/lactating women.