Iodine, a non-metallic trace element, is required by humans for the synthesis of thyroid hormones. Iodine deficiency is an important health problem throughout much of the world. iodine deficiency disorders (IDD) affect 750 million people throughout the world, and nearly 50 million people suffer from some degree of IDD-related brain damage.
    Nearly 2.2 million people throughout the world live in areas of iodine deficiency and risk its consequences.

Iodine plays an important role in the immune system where it supports the microbicidal activity of polymorphonuclear leukocytes.
    Iodine helps metabolise excess fat and is key for physical and mental development.

Adults should have 200 micrograms every day, pregnant women should have 220 micrograms.

Intake:

Recommended Dietary Allowance (RDA) for Iodine
Babies 0-6 months	110 mcg/day
Babies 7-12 months	130 mcg/day
Children 1 to 3 years	90 mcg/day
Children 4 to 8 years	90 mcg/day
Children 9 to 13 years	120 mcg/day
Teenagers 14 to 18	150 mcg/day
Adult	200 mcg/day
Pregnant women	220 mcg/day
Breastfeeding	290 mcg/day

Required in only trace amounts, iodine helps metabolise excess fat and is key for physical and mental development.
    Iodine is important for proper functioning of the thyroid gland and for the prevention of goiter, an enlargement of the thyroid gland.
    The condition of the hair, skin, nails and teeth are all dependent on the proper functioning of the thyroid as is the conversion of carotene to vitamin A.

The iodine content of most foods depends on the iodine content of the soil in which it was raised. Seafood is rich in iodine because marine animals can concentrate the iodine from seawater. Certain types of seaweed are also very rich in iodine.
    The table below lists the iodine content of some iodine-rich foods in micrograms (mcg). Because the iodine content of foods can vary considerably, these values should be considered approximate.