Iodine deficiency disorders in South Africa.

Iodine is an essential micronutrient, but iodine deficiency remains common worldwide, including many African countries. In South Africa endemic goitre was first noted in the 1920s. Several subsequent surveys have indicated its widespread persistence, despite the limited availability of iodised salt. The significance of nutritional iodine deficiency lies in the associated iodine deficiency disorders, which follow from maternal and fetal hypothyroidism. The extreme consequence is endemic cretinism, but much more prevalent are lesser degrees of intellectual and neurological deficits, with a potential reduction of intelligence scores in affected communities of more than 10%. Such severe consequences of iodine deficiency probably affect a significant proportion of South Africans. The control of iodine deficiency should be easy and inexpensive. Since the December 1995 legislation, all salt manufactured in South Africa must contain potassium iodate. Such supplementation is likely to cause a small increase in auto-immune thyroid disorders. This negative effect is slight in comparison with the potential benefit to millions.