Effect of excess iodine intake on thyroid on human health.
Level 5 - mechanism / opinion, no new human data
Narrative review of thyroid physiology and iodine excess mechanisms without systematic search methodology.
PubMed 28079354 · doi:10.23736/S0026-4806.17.04923-0
What was done
Narrative review examining iodine transport mechanisms, thyroid autoregulation (including the Wolff-Chaikoff effect), and the clinical effects of acute or chronic excessive iodine exposure from food, preservatives, and medications such as amiodarone.
What was found
The abstract reports recommended daily iodide intakes of 150 μg for adolescents/adults and 250 μg for pregnancy/lactation. It notes that large iodine doses reduce uptake, organification, and thyroglobulin proteolysis. No statistical or quantitative effect sizes are provided. The review describes that failure to escape organification inhibition causes transient hypothyroidism, while iodine excess can trigger autonomic hyperthyroidism in iodopenic areas or iodine-induced hyperthyroidism in iodine-abundant areas, with amiodarone capable of inducing either condition.
Why it matters
It outlines how excessive iodine exposure from dietary sources or medications can override normal thyroid protective mechanisms and induce either hypo- or hyperthyroidism.
Limits
The abstract describes a narrative overview without systematic search criteria, meta-analytic data, primary sample sizes, quantitative effect estimates, or statistical testing.
Cited by
- supports Excessive intake of iodine temporarily shuts down or pauses biochemical reactions in the thyroid gland.