Azizi F et al found similar results which noted that swelling of the thyroid and thyroglobulin levels were significantly reduced by iodine treatment. (33)
Iodine and hearing:
Hearing improved permanently in iodine-deficient children taking continuous iodine supplementation. Schoolchildren in areas of severe iodine deficiency were included in this study. (33)
Iron supplementation, anemia and intelligence:
Iron supplementation improved attention and concentration in women and adolescents and increased intelligence (IQ by 2.5 points) in women and children who were anemic. Fourteen randomized controlled trials were included. Iron supplementation had no effect on non-anemic individuals or on other cognitive outcomes (memory, psychomotor skills or school achievement). (34)