Iodine deficiency (leading to ‘goitre’) was endemic in parts of the UK in the 1930s and 40s, but was eradicated as milk intakes rose post war. Over recent decades, milk consumption has fallen considerably and now around 20% of teenage girls and young women have iodine intakes likely to be inadequate.
In a study of UK schoolgirls, half had mild iodine deficiency and mild to moderate deficiency was found in UK pregnant women.
Iodine is an essential component to thyroid hormones, which control metabolic rate (low levels promote weight gain) and is very important early in pregnancy for foetal brain development.
Very severe deficiency causes cretinism and maternal prenatal iodine levels in the UK have been linked with children’s IQ and reading ability at ages eight and nine.
Salt is often iodised in other countries, but this isn't done in the UK and would be at odds with recent campaigns to reduce salt intake. So, iodine status is one to watch.