At present, the only physiologic role known for iodine in the human body is in the synthesis of thyroid hormones by the thyroid gland.
Dietary sources The iodine content of food depends on the iodine content of the soil in which it is grown. The iodine present in the upper crust of earth is leached by glaciation and repeated flooding and is carried to the sea. Sea water is, therefore, a rich source of iodine. The seaweed located near coral reefs has an inherent biologic capacity to concentrate iodine from the sea. The reef fish which thrive on seaweed are rich in iodine.
Recommended daily intake of iodine
|0 - 6 months||15 (p) μg/kg/day|
|Males 10 - 18 years||135 (10-11 yrs)
110 (12 + yrs)
|Females 10 - 18 years||140 (10-11 yrs)
100 (12 + yrs)
|Males 19 - 65 years||130|
|Females 19 - 50 years||110|
|Females 51 - 65 years||110|
|Males 65 + years||130|
|Females 65 + years||110|
(o) Data expressed on a per kg body weight basis is sometimes preferred, and this data is as follows:
premature infants = 30 μg/kg/day
infants 0-12 months = 19 μg/kg/day
children 1 – 6 years = 6 μg/kg/day
children 7 – 11 = 4 μg/kg/day
adolescents and adults 12 + years = 2 μg/kg/day
pregnancy and lactation = 3.5 μg/kg/day
(p) In view of the high variability in body weights at these ages the RNIs are expressed as μg/kg body weight/day.
Average iodine content of foods (in μg/g)
|Fish (fresh water)||30||17–40|