Treating even mild iodine deficiencies can improve mental function in children, according to a small study.

Iodine is a chemical element necessary for normal growth and development. Because your body does not make iodine, it must be obtained in the diet. Severe iodine deficiency has long been known to cause mental impairment and other problems in children.

Researchers randomly assigned 184 mildly iodine-deficient children to take either a tablet containing 150 micrograms of iodine or a placebo pill every day for 28 weeks. At the end of the study, children in the iodine group showed an overall improvement on two standard cognitive tests that gauge problem-solving abilities.