iodization

Iodization is the practice of adding iodine to food products, most often table salt, to prevent iodine deficiency disorders. Iodine is an essential micronutrient required for thyroid hormone synthesis; deficiency can cause goiter, cretinism, hypothyroidism, and cognitive impairment, particularly during pregnancy and early childhood.

Public health programs began iodizing salt in the early 20th century, with notable early adoption in parts of Europe and the United States. The approach proved highly effective in reducing iodine deficiency disorders, and global efforts have led to widespread use of universal salt iodization under guidance from organizations such as the World Health Organization and UNICEF.

Iodization typically uses potassium iodate or potassium iodide and is added at production to achieve a target iodine content, commonly about 20-40 mg of iodine per kilogram of salt (ppm). The actual iodine intake depends on salt consumption, so requirements vary by country and dietary patterns.

Iodized salt is a central measure in eliminating IDD; many countries have universal salt iodization programs. Monitoring includes urinary iodine concentration in populations and surveys of iodized salt coverage. Excess iodine can trigger thyroid dysfunction in susceptible individuals, so programs balance adequate intake with safety and regular oversight.

Other foods and supplements, such as iodized oil or fortified bread, are used where salt iodization is challenging. Ongoing challenges include ensuring access in rural or conflict-affected areas, preventing salt adulteration, and addressing reduced salt consumption due to public health campaigns promoting lower salt intake.