General Information

CAS number: 7553-56-2
Functional Class:
  • Food Contaminant


Evaluation year: 1989
Comments: Iodine is an essential micronutrient. The nutritional requirement for iodine (under review by WHO) is currently considered to be in the range of 0.10 to 0.14 mg per person per day for adults (see potassium iodate). The Committee set a provisional maximum tolerable daily intake of 1 mg iodine/day (0.017 mg/kg bw) from all sources. This level may cause adverse effects for some individuals, e.g., people with thyroid disorders or people who are particularly sensitive to iodine.The Committee further recommended that physicians and public health authorities should be aware of the need to balance therapeutic need with potential iodine excess in relation to the use of iodine-containing drugs.
Intake: From air: 0.4 µg/person, not considered a significant source. From unpolluted waters: < 30 µg/day for drinking water containing 15 µg I/L. Dietary intake: mean = 1 mg/person; with high consumption of I-rich sources (seaweed) = several mg/person.
Tolerable Intake: PMTDI: 0.017 mg/kg bw/d, all sources
Meeting: 33
Report: TRS 776-JECFA 33/32
Tox Monograph: FAS 24-JECFA 33/267
Toxicological study
Pivotal Study: Epidemiological study of prison inmates exposed to iodinated water (Thomas et al. (1978), Stockton & Thomas (1978), Thomas et al. (1969), and Freund et al. (1966)): 750 men and women that had ingested approximately one to two mg of iodine per day for various time periods. No adverse effects were reported except in four women who were hyperthyroid before entering became more symptomatic receiving the iodinated water supply, and that of 15 inmates tested, two had impaired organification of thyroidal iodine.
Animal specie: Human
Effect: Suppression radioactive iodine uptake by thyroid/impaired organification of thyroidal iodine
PMTDI: 0.017 mg/kg bw/d, all sources
Point of departure: 1 mg/d