Iodine deficiency is creeping back. Vegans, vegetarians and pregnant women are most at risk

Iodine deficiency is often seen as a problem of the past, but this isn't entirely true. During the 20th century, the iodization of salt became one of the most effective public health interventions for preventing conditions caused by a lack of this mineral, including goiter (enlargement of the thyroid gland) and preventable damage to neurological development.