Two thirds of your body's iodine is found in your thyroid gland. It is an important component of thyroid hormones-essential for reproduction. Since your thyroid also controls your metabolism, a lack of this micronutrient may show up in weight gain, lack of energy, and sluggish mental reactions. On the other hand, proper levels of iodine will help you diet by burning off extra fat, give you more energy, and heighten your mental sharpness. Iodine also promotes healthy teeth, skin, nails, and hair.

Other Benefits:

• Helps convert beta-carotene into vitamin A.
• Can help head off atherosclerosis by making sure your body synthesizes cholesterol properly.
• Iodide tablets can help protect against radiation from nuclear fallout.

Signs of Deficiency:

• In newborns: cretinism-delayed growth and swollen features
• In others: goiter enlarged thyroid gland
• Lack may lead to
  • Slowed mental reactions
  • Dry hair
  • Hardening of the arteries
  • Obesity and lethargy
  • Intolerance to cold
• Deficiency during pregnancy and infancy can produce mental and physical retardation
• Reversible with iodine supplements
• Deficiencies rare today

Sources:

• Seafoods
• Iodized and sea salts
• Seaweed (kelp)
• Vegetables grown in iodine-rich soil
• Onions
• Food colors and additives

RDA: 150 mcg for adults

Optimal Level: From dietary sources

Maximum: 1,000 mcg

Signs of Toxicity: Goiter (swollen thyroid)