Deficiency prevention uses population measures such as iodized salt; supplement dosing in thyroid disease is individualized care
Reviewed · Published
Iodine
A thyroid-hormone component regulating growth and metabolism.
Established functions
- A thyroid-hormone component regulating growth and metabolism.
Dietary sources
- kombu
- wakame
- cod
Claims and evidence
Claims that Iodine alone prevents or treats disease, or invariably improves health without deficiency, are unsupported.
Japanese reference amounts
- Japanese adults (age and sex as specified): Adults: 140 µg/day (RDA)
Amounts studied
- Deficiency prevention uses population measures such as iodized salt; supplement dosing in thyroid disease is individualized care
Tolerable upper limits
- Adults: 3,000 µg/day
Forms and bioavailability
Supplement forms: potassium iodide, kelp-derived iodine
- Seaweed content varies widely, with kombu especially concentrated.
Safety and interactions
Adverse effects
- hypo- or hyperthyroidism
- goiter
Medicine and nutrient interactions
- amiodarone, lithium, antithyroid medicines
Contraindications and cautions
- Avoid self-supplementing with thyroid disease.
Practical selection
- Compare Iodine amount per serving, form, allergens, and batch testing; prefer a single-ingredient product suited to the intended use.
Sources and review
- Dietary Reference Intakes for Japanese (2025)Ministry of Health, Labour and Welfare (Japan)
- NIH ODS mineral fact sheetsNIH Office of Dietary Supplements
Daiki Minaki (editorial and evidence review) ·