Thyroid and iodine nutritional status: a UK perspective.

Iodine is an essential component of the thyroid hormones, which play a crucial role in brain and neurological development. At least one-third of the world's population is estimated to be iodine deficient predominantly in developing countries. Recently concern had also been expressed about the iodine status in industrialised countries such as the UK. A recent survey of the UK iodine status found that that more than two-thirds of schoolgirls aged 14-15 years were iodine deficient due to the reduced milk intake. Maternal iodine deficiency in pregnancy is correlated with cognitive outcomes such as intelligence quotient and reading ability in offspring. No randomised trial data exist for iodine supplementation in mild-moderate iodine-deficient pregnant women. It is possible to combine population interventions to reduce population salt intake with salt iodisation programmes in order to maintain adequate levels of iodine nutrition.