Iodine

Figure 1. The crystal structure of Iodine.

Iodine is a chemical element with the symbol I and atomic number 53. Iodine is the heaviest essential mineral nutrient and is required in the synthesis of the growth-regulating thyroid hormones thyroxine and triiodothyronine. Iodine deficiency affects about two billion people and is the leading preventable cause of intellectual disabilities.

Within the human body, about 30% of Iodine is found in thyroid tissues and hormones. The remaining 70% are found throughout the body including the mammary glands, eyes, gastric mucosa, fetal thymus, cerebro-spinal fluid and choroid plexus, arterial walls, the cervix, and salivary glands.

Food Sources

Seafood is a good source of Iodine, such as many fish, seaweed, and shellfish.

Taken as a Dietary Supplement

The recommended daily intake level of Iodine is:

• 0.11mg-0.13mg for infants up to 12 months
• 0.09mg for children up to eight years
• 0.13mg for children up to 13 years
• 0.15mg for adults
• 0.22mg for pregnant women
• 0.29mg for lactating women

The Tolerable Upper Intake Level for adults is 1.1mg per day. The thyroid gland needs no more than 0.07mg per day to synthesise the requisite daily amounts of thyroxine and triiodothyronine. Iodine supplements are mainly consumed to help with Iodine deficiency conditions, including goiter, hypothyroidism, and some other thyroid disorders.