Needed only in trace amounts, Iodine helps to metabolize excess fat and is important for physical and mental development. It is also needed for a healthy thyroid gland and the prevention of goiter.
Iodine deficiency in children may result in mental retardation. In addition, Iodine deficiency has been linked to breast cancer and is associated with fatigue, neonatal hypothyroidism (cretinism), and weight gain.
Excessive Iodine intake (over thirty times the RDA) can produce a metallic taste and sores in the mouth, swollen salivary glands, diarrhea, and vomiting.
Natural Food Sources of Iodine
Natural Food Sources of Iodine include:
spinach (but see Comments below)
Some foods block the uptake of Iodine into the thyroid gland when eaten raw in large amounts.
If you have an underactive thyroid, you should limit your consumption of these foods.
The best Iodine supplements are simply using sea salt or iodized table salt.