Iodine deficiency is a major health problem worldwide, but a new study points to the potential downsides of too much iodine.
Iodine is a mineral found in iodized salt, seafood, eggs, dairy and some breads. It is used by the thyroid gland to help regulate metabolism and development, especially in babies and children.
Iodine deficiency during fetal and early-childhood development is a leading cause of brain impairments in much of the world. So most research has been directed at the effects of inadequate iodine.
Less is known about how much iodine is too much. So for the new study, reported in the American Journal of Clinical Nutrition, Chinese researchers randomly assigned healthy adults to take various doses of iodine supplements for four weeks.
Read More: How much iodine is too much?