Iodine
Iodine deficiency affects an estimated 60 million (5% of) school-age children and is the leading cause of preventable mental retardation worldwide. School children living in iodine deficient areas have poorer cognitive abilities than children living in iodine sufficient areas. Iodine Deficiency Disorders (IDD) can be eliminated by preventive measures using iodine administered in salt, oil or some other vehicle.
For more information on Iodine deficiency, search for articles in the Iodine Bibliography and/or visit the International Council for the Control of Iodine Deficiency Disorders.