Iodine

cross_nutrient

false

evidence_location

Primary indexed abstract.

experimental_model

Four-week randomized double-blind placebo-controlled dose trial in 256 euthyroid Chinese adults

exposure

Twelve groups received 0–2000 micrograms/day supplemental iodine. Mean reported dietary and salt iodine contributions were 105 ± 25 and 258 ± 101 micrograms/day.

limitations

Short study with small dose groups. Total background iodine differs among participants; the approximately 800 micrograms/day total at the 400-microgram supplement is the authors’ estimate, not a universal safe/unsafe threshold. Exact chemical formulation not verified from abstract. These percentages are reported study-group findings, not an individual risk calculator. The authors estimated about 800 micrograms/day total intake in the 400-microgram supplement group; adding two overall mean background values is not a group-specific intake measurement.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

Higher iodine exposure produced abnormal thyroid-function classifications in some participants.

primary_references

[iod-clin-sang2012] Exploration of the safe upper level of iodine intake in euthyroid Chinese adults: a randomized double-blind trial. (2012). https://pubmed.ncbi.nlm.nih.gov/22205314/ DOI: 10.3945/ajcn.111.028001

tissue_or_cell_type

Serum thyroid indices, ultrasound and urinary iodine

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1468–1480

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Four-week randomized double-blind placebo-controlled dose trial in 256 euthyroid Chinese adults · source_derived_draft · unverified_draft

### iod-clin-excess-subclinical Subclinical hypothyroidism occurred in 5% of the 400-microgram/day supplement group and 15–47% of the 500–2000-microgram/day groups. Condition category: normal nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: Higher iodine exposure produced abnormal thyroid-function classifications in some participants. organism: Homo sapiens tissue_or_cell_type: Serum thyroid indices, ultrasound and urinary iodine experimental_model: Four-week randomized double-blind placebo-controlled dose trial in 256 euthyroid Chinese adults limitations: Short study with small dose groups. Total background iodine differs among participants; the approximately 800 micrograms/day total at the 400-microgram supplement is the authors’ estimate, not a universal safe/unsafe threshold. Exact chemical formulation not verified from abstract. These percentages are reported study-group findings, not an individual risk calculator. The authors estimated about 800 micrograms/day total intake in the 400-microgram supplement group; adding two overall mean background values is not a group-specific intake measurement. exposure: Twelve groups received 0–2000 micrograms/day supplemental iodine. Mean reported dietary and salt iodine contributions were 105 ± 25 and 258 ± 101 micrograms/day. cross_nutrient: false evidence_location: Primary indexed abstract. [iod-clin-sang2012] Exploration of the safe upper level of iodine intake in euthyroid Chinese adults: a randomized double-blind trial. (2012). https://pubmed.ncbi.nlm.nih.gov/22205314/ DOI: 10.3945/ajcn.111.028001

cross_nutrient

false

evidence_location

Primary indexed abstract.

experimental_model

Four-week randomized double-blind placebo-controlled dose trial in 256 euthyroid Chinese adults

exposure

Twelve groups received 0–2000 micrograms/day supplemental iodine. Mean reported dietary and salt iodine contributions were 105 ± 25 and 258 ± 101 micrograms/day.

limitations

Short study with small dose groups. Total background iodine differs among participants; the approximately 800 micrograms/day total at the 400-microgram supplement is the authors’ estimate, not a universal safe/unsafe threshold. Exact chemical formulation not verified from abstract. Baseline participants were euthyroid; increased TSH alone does not identify the molecular inhibition step.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

More iodine raised TSH in this short dose-ranging trial.

primary_references

[iod-clin-sang2012] Exploration of the safe upper level of iodine intake in euthyroid Chinese adults: a randomized double-blind trial. (2012). https://pubmed.ncbi.nlm.nih.gov/22205314/ DOI: 10.3945/ajcn.111.028001

tissue_or_cell_type

Serum thyroid indices, ultrasound and urinary iodine

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1454–1466

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Four-week randomized double-blind placebo-controlled dose trial in 256 euthyroid Chinese adults · source_derived_draft · unverified_draft

### iod-clin-excess-tsh All iodide-supplemented groups had significant increases in TSH and median urinary iodine relative to placebo after four weeks (P<0.05). Condition category: normal nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: More iodine raised TSH in this short dose-ranging trial. organism: Homo sapiens tissue_or_cell_type: Serum thyroid indices, ultrasound and urinary iodine experimental_model: Four-week randomized double-blind placebo-controlled dose trial in 256 euthyroid Chinese adults limitations: Short study with small dose groups. Total background iodine differs among participants; the approximately 800 micrograms/day total at the 400-microgram supplement is the authors’ estimate, not a universal safe/unsafe threshold. Exact chemical formulation not verified from abstract. Baseline participants were euthyroid; increased TSH alone does not identify the molecular inhibition step. exposure: Twelve groups received 0–2000 micrograms/day supplemental iodine. Mean reported dietary and salt iodine contributions were 105 ± 25 and 258 ± 101 micrograms/day. cross_nutrient: false evidence_location: Primary indexed abstract. [iod-clin-sang2012] Exploration of the safe upper level of iodine intake in euthyroid Chinese adults: a randomized double-blind trial. (2012). https://pubmed.ncbi.nlm.nih.gov/22205314/ DOI: 10.3945/ajcn.111.028001

cross_nutrient

false

evidence_location

Primary indexed abstract.

experimental_model

Prospective five-year observational follow-up in three Chinese regions;3761 enrolled and 3018 followed

exposure

Regional baseline median urinary iodine 84, 243 and 651 micrograms/L; followed 1999–2004.

limitations

Regional exposure is not randomized individual dosing; confounding and baseline susceptibility may contribute. Median urinary iodine defines cohort exposure, not an individual disease threshold. Association does not establish the immune mechanism or show that every person with antibodies responds identically to iodine.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

The same cohort also found more autoimmune thyroiditis in the higher-exposure regions.

primary_references

[iod-clin-teng2006] Effect of iodine intake on thyroid diseases in China. (2006). https://pubmed.ncbi.nlm.nih.gov/16807415/ DOI: 10.1056/nejmoa054022

tissue_or_cell_type

Serum thyroid function/antibodies and thyroid ultrasound

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1496–1508

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Prospective five-year observational follow-up in three Chinese regions;3761 enrolled and 3018 followed · source_derived_draft · unverified_draft

### iod-clin-regional-autoimmunity Five-year autoimmune thyroiditis incidence was 0.2%, 1.0% and 1.3% across the three increasing regional iodine-exposure categories. Condition category: normal nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: The same cohort also found more autoimmune thyroiditis in the higher-exposure regions. organism: Homo sapiens tissue_or_cell_type: Serum thyroid function/antibodies and thyroid ultrasound experimental_model: Prospective five-year observational follow-up in three Chinese regions;3761 enrolled and 3018 followed limitations: Regional exposure is not randomized individual dosing; confounding and baseline susceptibility may contribute. Median urinary iodine defines cohort exposure, not an individual disease threshold. Association does not establish the immune mechanism or show that every person with antibodies responds identically to iodine. exposure: Regional baseline median urinary iodine 84, 243 and 651 micrograms/L; followed 1999–2004. cross_nutrient: false evidence_location: Primary indexed abstract. [iod-clin-teng2006] Effect of iodine intake on thyroid diseases in China. (2006). https://pubmed.ncbi.nlm.nih.gov/16807415/ DOI: 10.1056/nejmoa054022

cross_nutrient

false

evidence_location

Primary indexed abstract.

experimental_model

Prospective five-year observational follow-up in three Chinese regions;3761 enrolled and 3018 followed

exposure

Regional baseline median urinary iodine 84, 243 and 651 micrograms/L; followed 1999–2004.

limitations

Regional exposure is not randomized individual dosing; confounding and baseline susceptibility may contribute. Median urinary iodine defines cohort exposure, not an individual disease threshold. The corresponding overt hypothyroidism incidences were 0.2%, 0.5% and 0.3%, so the study does not show a monotonic rise for every thyroid outcome.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

Higher regional iodine exposure was associated with more subclinical hypothyroidism.

primary_references

[iod-clin-teng2006] Effect of iodine intake on thyroid diseases in China. (2006). https://pubmed.ncbi.nlm.nih.gov/16807415/ DOI: 10.1056/nejmoa054022

tissue_or_cell_type

Serum thyroid function/antibodies and thyroid ultrasound

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1482–1494

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Prospective five-year observational follow-up in three Chinese regions;3761 enrolled and 3018 followed · source_derived_draft · unverified_draft

### iod-clin-regional-subclinical Five-year subclinical hypothyroidism incidence was 0.2%, 2.6% and 2.9% in the regions with mildly deficient, more-than-adequate and excessive iodine exposure, respectively. Condition category: normal nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: Higher regional iodine exposure was associated with more subclinical hypothyroidism. organism: Homo sapiens tissue_or_cell_type: Serum thyroid function/antibodies and thyroid ultrasound experimental_model: Prospective five-year observational follow-up in three Chinese regions;3761 enrolled and 3018 followed limitations: Regional exposure is not randomized individual dosing; confounding and baseline susceptibility may contribute. Median urinary iodine defines cohort exposure, not an individual disease threshold. The corresponding overt hypothyroidism incidences were 0.2%, 0.5% and 0.3%, so the study does not show a monotonic rise for every thyroid outcome. exposure: Regional baseline median urinary iodine 84, 243 and 651 micrograms/L; followed 1999–2004. cross_nutrient: false evidence_location: Primary indexed abstract. [iod-clin-teng2006] Effect of iodine intake on thyroid diseases in China. (2006). https://pubmed.ncbi.nlm.nih.gov/16807415/ DOI: 10.1056/nejmoa054022

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

false

evidence_location

Primary full PDF Methods, Results, Tables 1–2 and Discussion, pp.108–114.

experimental_model

Randomized double-blind placebo-controlled 24-week trial in 310 moderately iodine-deficient Albanian children aged 10–12

exposure

One supervised oral dose of iodized poppyseed oil containing 400 mg iodine versus sunflower-oil placebo; baseline median urinary iodine 43 micrograms/L, 87% goitrous; iodine 159/placebo 151 randomized.

limitations

Baseline groups differed on four psychological tests; analyses adjusted for baseline score, school and sex. Follow-up was 24 weeks, with no proof of lasting IQ or school-performance improvement. Symbol-search test-retest reliability was modest. Dose is a historical depot intervention, not daily intake. One of four improved tests in a seven-test battery; a positive result on this task is not an effect size for general intelligence.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

In this study, iodine repletion improved rapid object naming.

primary_references

[iod-clin-albania2006] Iodine supplementation improves cognition in iodine-deficient schoolchildren in Albania: a randomized, controlled, double-blind study. (2006). https://pubmed.ncbi.nlm.nih.gov/16400058/ DOI: 10.1093/ajcn/83.1.108

tissue_or_cell_type

Thyroid hormones and cognitive/motor testing

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1342–1354

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Randomized double-blind placebo-controlled 24-week trial in 310 moderately iodine-deficient Albanian children aged 10–12 · source_derived_draft · unverified_draft

### iod-clin-albania-naming Iodine treatment improved rapid object naming performance compared with placebo at 24 weeks (reported adjusted P<0.0001). Condition category: nutrient_deficiency nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: In this study, iodine repletion improved rapid object naming. organism: Homo sapiens tissue_or_cell_type: Thyroid hormones and cognitive/motor testing experimental_model: Randomized double-blind placebo-controlled 24-week trial in 310 moderately iodine-deficient Albanian children aged 10–12 limitations: Baseline groups differed on four psychological tests; analyses adjusted for baseline score, school and sex. Follow-up was 24 weeks, with no proof of lasting IQ or school-performance improvement. Symbol-search test-retest reliability was modest. Dose is a historical depot intervention, not daily intake. One of four improved tests in a seven-test battery; a positive result on this task is not an effect size for general intelligence. exposure: One supervised oral dose of iodized poppyseed oil containing 400 mg iodine versus sunflower-oil placebo; baseline median urinary iodine 43 micrograms/L, 87% goitrous; iodine 159/placebo 151 randomized. cross_nutrient: false evidence_location: Primary full PDF Methods, Results, Tables 1–2 and Discussion, pp.108–114. [iod-clin-albania2006] Iodine supplementation improves cognition in iodine-deficient schoolchildren in Albania: a randomized, controlled, double-blind study. (2006). https://pubmed.ncbi.nlm.nih.gov/16400058/ DOI: 10.1093/ajcn/83.1.108

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

false

evidence_location

Primary full PDF Methods, Results, Tables 1–2 and Discussion, pp.108–114.

experimental_model

Randomized double-blind placebo-controlled 24-week trial in 310 moderately iodine-deficient Albanian children aged 10–12

exposure

One supervised oral dose of iodized poppyseed oil containing 400 mg iodine versus sunflower-oil placebo; baseline median urinary iodine 43 micrograms/L, 87% goitrous; iodine 159/placebo 151 randomized.

limitations

Baseline groups differed on four psychological tests; analyses adjusted for baseline score, school and sex. Follow-up was 24 weeks, with no proof of lasting IQ or school-performance improvement. Symbol-search test-retest reliability was modest. Dose is a historical depot intervention, not daily intake. One of four improved tests in a seven-test battery; a positive result on this task is not an effect size for general intelligence.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

In this study, iodine repletion improved Raven’s Coloured Progressive Matrices.

primary_references

[iod-clin-albania2006] Iodine supplementation improves cognition in iodine-deficient schoolchildren in Albania: a randomized, controlled, double-blind study. (2006). https://pubmed.ncbi.nlm.nih.gov/16400058/ DOI: 10.1093/ajcn/83.1.108

tissue_or_cell_type

Thyroid hormones and cognitive/motor testing

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1356–1368

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Randomized double-blind placebo-controlled 24-week trial in 310 moderately iodine-deficient Albanian children aged 10–12 · source_derived_draft · unverified_draft

### iod-clin-albania-raven Iodine treatment improved Raven’s Coloured Progressive Matrices performance compared with placebo at 24 weeks (reported adjusted P<0.0001). Condition category: nutrient_deficiency nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: In this study, iodine repletion improved Raven’s Coloured Progressive Matrices. organism: Homo sapiens tissue_or_cell_type: Thyroid hormones and cognitive/motor testing experimental_model: Randomized double-blind placebo-controlled 24-week trial in 310 moderately iodine-deficient Albanian children aged 10–12 limitations: Baseline groups differed on four psychological tests; analyses adjusted for baseline score, school and sex. Follow-up was 24 weeks, with no proof of lasting IQ or school-performance improvement. Symbol-search test-retest reliability was modest. Dose is a historical depot intervention, not daily intake. One of four improved tests in a seven-test battery; a positive result on this task is not an effect size for general intelligence. exposure: One supervised oral dose of iodized poppyseed oil containing 400 mg iodine versus sunflower-oil placebo; baseline median urinary iodine 43 micrograms/L, 87% goitrous; iodine 159/placebo 151 randomized. cross_nutrient: false evidence_location: Primary full PDF Methods, Results, Tables 1–2 and Discussion, pp.108–114. [iod-clin-albania2006] Iodine supplementation improves cognition in iodine-deficient schoolchildren in Albania: a randomized, controlled, double-blind study. (2006). https://pubmed.ncbi.nlm.nih.gov/16400058/ DOI: 10.1093/ajcn/83.1.108

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

false

evidence_location

Primary full PDF Methods, Results, Tables 1–2 and Discussion, pp.108–114.

experimental_model

Randomized double-blind placebo-controlled 24-week trial in 310 moderately iodine-deficient Albanian children aged 10–12

exposure

One supervised oral dose of iodized poppyseed oil containing 400 mg iodine versus sunflower-oil placebo; baseline median urinary iodine 43 micrograms/L, 87% goitrous; iodine 159/placebo 151 randomized.

limitations

Baseline groups differed on four psychological tests; analyses adjusted for baseline score, school and sex. Follow-up was 24 weeks, with no proof of lasting IQ or school-performance improvement. Symbol-search test-retest reliability was modest. Dose is a historical depot intervention, not daily intake. One of four improved tests in a seven-test battery; a positive result on this task is not an effect size for general intelligence.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

In this study, iodine repletion improved symbol search.

primary_references

[iod-clin-albania2006] Iodine supplementation improves cognition in iodine-deficient schoolchildren in Albania: a randomized, controlled, double-blind study. (2006). https://pubmed.ncbi.nlm.nih.gov/16400058/ DOI: 10.1093/ajcn/83.1.108

tissue_or_cell_type

Thyroid hormones and cognitive/motor testing

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1328–1340

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Randomized double-blind placebo-controlled 24-week trial in 310 moderately iodine-deficient Albanian children aged 10–12 · source_derived_draft · unverified_draft

### iod-clin-albania-symbol Iodine treatment improved symbol search performance compared with placebo at 24 weeks (reported adjusted P<0.0001). Condition category: nutrient_deficiency nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: In this study, iodine repletion improved symbol search. organism: Homo sapiens tissue_or_cell_type: Thyroid hormones and cognitive/motor testing experimental_model: Randomized double-blind placebo-controlled 24-week trial in 310 moderately iodine-deficient Albanian children aged 10–12 limitations: Baseline groups differed on four psychological tests; analyses adjusted for baseline score, school and sex. Follow-up was 24 weeks, with no proof of lasting IQ or school-performance improvement. Symbol-search test-retest reliability was modest. Dose is a historical depot intervention, not daily intake. One of four improved tests in a seven-test battery; a positive result on this task is not an effect size for general intelligence. exposure: One supervised oral dose of iodized poppyseed oil containing 400 mg iodine versus sunflower-oil placebo; baseline median urinary iodine 43 micrograms/L, 87% goitrous; iodine 159/placebo 151 randomized. cross_nutrient: false evidence_location: Primary full PDF Methods, Results, Tables 1–2 and Discussion, pp.108–114. [iod-clin-albania2006] Iodine supplementation improves cognition in iodine-deficient schoolchildren in Albania: a randomized, controlled, double-blind study. (2006). https://pubmed.ncbi.nlm.nih.gov/16400058/ DOI: 10.1093/ajcn/83.1.108

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

false

evidence_location

Primary full PDF Methods, Results, Tables 1–2 and Discussion, pp.108–114.

experimental_model

Randomized double-blind placebo-controlled 24-week trial in 310 moderately iodine-deficient Albanian children aged 10–12

exposure

One supervised oral dose of iodized poppyseed oil containing 400 mg iodine versus sunflower-oil placebo; baseline median urinary iodine 43 micrograms/L, 87% goitrous; iodine 159/placebo 151 randomized.

limitations

Baseline groups differed on four psychological tests; analyses adjusted for baseline score, school and sex. Follow-up was 24 weeks, with no proof of lasting IQ or school-performance improvement. Symbol-search test-retest reliability was modest. Dose is a historical depot intervention, not daily intake. One of four improved tests in a seven-test battery; a positive result on this task is not an effect size for general intelligence.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

In this study, iodine repletion improved rapid target marking.

primary_references

[iod-clin-albania2006] Iodine supplementation improves cognition in iodine-deficient schoolchildren in Albania: a randomized, controlled, double-blind study. (2006). https://pubmed.ncbi.nlm.nih.gov/16400058/ DOI: 10.1093/ajcn/83.1.108

tissue_or_cell_type

Thyroid hormones and cognitive/motor testing

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1314–1326

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Randomized double-blind placebo-controlled 24-week trial in 310 moderately iodine-deficient Albanian children aged 10–12 · source_derived_draft · unverified_draft

### iod-clin-albania-target Iodine treatment improved rapid target marking performance compared with placebo at 24 weeks (reported adjusted P<0.0001). Condition category: nutrient_deficiency nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: In this study, iodine repletion improved rapid target marking. organism: Homo sapiens tissue_or_cell_type: Thyroid hormones and cognitive/motor testing experimental_model: Randomized double-blind placebo-controlled 24-week trial in 310 moderately iodine-deficient Albanian children aged 10–12 limitations: Baseline groups differed on four psychological tests; analyses adjusted for baseline score, school and sex. Follow-up was 24 weeks, with no proof of lasting IQ or school-performance improvement. Symbol-search test-retest reliability was modest. Dose is a historical depot intervention, not daily intake. One of four improved tests in a seven-test battery; a positive result on this task is not an effect size for general intelligence. exposure: One supervised oral dose of iodized poppyseed oil containing 400 mg iodine versus sunflower-oil placebo; baseline median urinary iodine 43 micrograms/L, 87% goitrous; iodine 159/placebo 151 randomized. cross_nutrient: false evidence_location: Primary full PDF Methods, Results, Tables 1–2 and Discussion, pp.108–114. [iod-clin-albania2006] Iodine supplementation improves cognition in iodine-deficient schoolchildren in Albania: a randomized, controlled, double-blind study. (2006). https://pubmed.ncbi.nlm.nih.gov/16400058/ DOI: 10.1093/ajcn/83.1.108

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

false

evidence_location

Primary full PDF Methods, Results, Tables 1–2 and Discussion, pp.108–114.

experimental_model

Randomized double-blind placebo-controlled 24-week trial in 310 moderately iodine-deficient Albanian children aged 10–12

exposure

One supervised oral dose of iodized poppyseed oil containing 400 mg iodine versus sunflower-oil placebo; baseline median urinary iodine 43 micrograms/L, 87% goitrous; iodine 159/placebo 151 randomized.

limitations

Baseline groups differed on four psychological tests; analyses adjusted for baseline score, school and sex. Follow-up was 24 weeks, with no proof of lasting IQ or school-performance improvement. Symbol-search test-retest reliability was modest. Dose is a historical depot intervention, not daily intake. The 40% figure is a within-treatment change described in the abstract, not a verified adjusted between-group estimate.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

Iodine repletion restored thyroid hormone status in these moderately deficient children.

primary_references

[iod-clin-albania2006] Iodine supplementation improves cognition in iodine-deficient schoolchildren in Albania: a randomized, controlled, double-blind study. (2006). https://pubmed.ncbi.nlm.nih.gov/16400058/ DOI: 10.1093/ajcn/83.1.108

tissue_or_cell_type

Thyroid hormones and cognitive/motor testing

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1300–1312

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Randomized double-blind placebo-controlled 24-week trial in 310 moderately iodine-deficient Albanian children aged 10–12 · source_derived_draft · unverified_draft

### iod-clin-albania-thyroxine At 24 weeks, mean total T4 in iodine-treated children was approximately 40% higher than baseline and hypothyroxinemia prevalence was below 1%; corresponding placebo-group status did not improve significantly. Condition category: nutrient_deficiency nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: Iodine repletion restored thyroid hormone status in these moderately deficient children. organism: Homo sapiens tissue_or_cell_type: Thyroid hormones and cognitive/motor testing experimental_model: Randomized double-blind placebo-controlled 24-week trial in 310 moderately iodine-deficient Albanian children aged 10–12 limitations: Baseline groups differed on four psychological tests; analyses adjusted for baseline score, school and sex. Follow-up was 24 weeks, with no proof of lasting IQ or school-performance improvement. Symbol-search test-retest reliability was modest. Dose is a historical depot intervention, not daily intake. The 40% figure is a within-treatment change described in the abstract, not a verified adjusted between-group estimate. exposure: One supervised oral dose of iodized poppyseed oil containing 400 mg iodine versus sunflower-oil placebo; baseline median urinary iodine 43 micrograms/L, 87% goitrous; iodine 159/placebo 151 randomized. cross_nutrient: false evidence_location: Primary full PDF Methods, Results, Tables 1–2 and Discussion, pp.108–114. [iod-clin-albania2006] Iodine supplementation improves cognition in iodine-deficient schoolchildren in Albania: a randomized, controlled, double-blind study. (2006). https://pubmed.ncbi.nlm.nih.gov/16400058/ DOI: 10.1093/ajcn/83.1.108

cross_nutrient

false

evidence_location

Primary indexed abstract.

experimental_model

Twenty-one-year prospective population-register study in two open Danish cohorts, initially 533969 residents

exposure

Mandatory salt iodization at 13 ppm from mid 2000; western cohort previously moderately deficient and eastern mildly deficient; eastern follow-up only through 2008, western through 2017.

limitations

Population trend rather than randomized individual causation; age composition, diagnostic testing and prior thyroid autonomy can influence rates. Early rise and later fall are successive phases, not competing claims.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

Thyrotoxicosis increased during the early years after iodine supply changed.

primary_references

[iod-clin-denmark2018] Thyrotoxicosis after iodine fortification. A 21-year Danish population-based study. (2018). https://pubmed.ncbi.nlm.nih.gov/29851122/ DOI: 10.1111/cen.13751

tissue_or_cell_type

Incident overt biochemical thyrotoxicosis identified from thyroid tests

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1510–1522

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Twenty-one-year prospective population-register study in two open Danish cohorts, initially 533969 residents · source_derived_draft · unverified_draft

### iod-clin-danish-early-rise After iodization, standardized thyrotoxicosis incidence initially rose 39% in the previously moderately deficient cohort and 52% in the mildly deficient cohort, peaking in 2000–2001 and 2004–2005 respectively. Condition category: normal nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: Thyrotoxicosis increased during the early years after iodine supply changed. organism: Homo sapiens tissue_or_cell_type: Incident overt biochemical thyrotoxicosis identified from thyroid tests experimental_model: Twenty-one-year prospective population-register study in two open Danish cohorts, initially 533969 residents limitations: Population trend rather than randomized individual causation; age composition, diagnostic testing and prior thyroid autonomy can influence rates. Early rise and later fall are successive phases, not competing claims. exposure: Mandatory salt iodization at 13 ppm from mid 2000; western cohort previously moderately deficient and eastern mildly deficient; eastern follow-up only through 2008, western through 2017. cross_nutrient: false evidence_location: Primary indexed abstract. [iod-clin-denmark2018] Thyrotoxicosis after iodine fortification. A 21-year Danish population-based study. (2018). https://pubmed.ncbi.nlm.nih.gov/29851122/ DOI: 10.1111/cen.13751

cross_nutrient

false

evidence_location

Primary indexed abstract.

experimental_model

Twenty-one-year prospective population-register study in two open Danish cohorts, initially 533969 residents

exposure

Mandatory salt iodization at 13 ppm from mid 2000; western cohort previously moderately deficient and eastern mildly deficient; eastern follow-up only through 2008, western through 2017.

limitations

Population trend rather than randomized individual causation; age composition, diagnostic testing and prior thyroid autonomy can influence rates. Early rise and later fall are successive phases, not competing claims. Only the western cohort continued to 2017. The decline was strongest among older people; this is not a claim that every thyroid outcome improved.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

The later population pattern differed from the early rise.

primary_references

[iod-clin-denmark2018] Thyrotoxicosis after iodine fortification. A 21-year Danish population-based study. (2018). https://pubmed.ncbi.nlm.nih.gov/29851122/ DOI: 10.1111/cen.13751

tissue_or_cell_type

Incident overt biochemical thyrotoxicosis identified from thyroid tests

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1524–1536

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Twenty-one-year prospective population-register study in two open Danish cohorts, initially 533969 residents · source_derived_draft · unverified_draft

### iod-clin-danish-late-decline Incidence returned to baseline or below by 2008; in the western, previously moderately deficient cohort it was 33% below baseline in 2016–2017. Condition category: normal nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: The later population pattern differed from the early rise. organism: Homo sapiens tissue_or_cell_type: Incident overt biochemical thyrotoxicosis identified from thyroid tests experimental_model: Twenty-one-year prospective population-register study in two open Danish cohorts, initially 533969 residents limitations: Population trend rather than randomized individual causation; age composition, diagnostic testing and prior thyroid autonomy can influence rates. Early rise and later fall are successive phases, not competing claims. Only the western cohort continued to 2017. The decline was strongest among older people; this is not a claim that every thyroid outcome improved. exposure: Mandatory salt iodization at 13 ppm from mid 2000; western cohort previously moderately deficient and eastern mildly deficient; eastern follow-up only through 2008, western through 2017. cross_nutrient: false evidence_location: Primary indexed abstract. [iod-clin-denmark2018] Thyrotoxicosis after iodine fortification. A 21-year Danish population-based study. (2018). https://pubmed.ncbi.nlm.nih.gov/29851122/ DOI: 10.1111/cen.13751

availability_state

biomarker_context Imported condition classification; unverified.

cross_nutrient

false

evidence_location

Primary indexed abstract.

experimental_model

Assay-standardization study in 700 iodine-sufficient euthyroid anti-Tg-antibody-negative children aged 5–14 and separate 10-month iodized-salt intervention

exposure

International reference sample and longitudinal measurements before, 5 months and 10 months after salt iodization in deficient children.

limitations

Assay-specific pediatric reference distribution; not a universal adult/pregnancy threshold. Anti-Tg-antibody-positive children were excluded from the reference sample; antibody interference and other thyroid diseases remain relevant.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

The study established a reference distribution for a particular pediatric assay.

primary_references

[iod-clin-tg2006] Assessment of iodine status using dried blood spot thyroglobulin: development of reference material and establishment of an international reference range in iodine-sufficient children. (2006). https://pubmed.ncbi.nlm.nih.gov/16968789/ DOI: 10.1210/jc.2006-1370

tissue_or_cell_type

Dried whole-blood thyroglobulin assay

trigger_kind

biomarker_context Imported condition classification; unverified.

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1594–1606

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Assay-standardization study in 700 iodine-sufficient euthyroid anti-Tg-antibody-negative children aged 5–14 and separate 10-month iodized-salt intervention · source_derived_draft · unverified_draft

### iod-clin-dbs-tg-reference The third and 97th percentiles of the standardized dried-blood-spot Tg assay were 4 and 40 micrograms/L in the 700 iodine-sufficient, euthyroid, anti-Tg-negative children. Condition category: biomarker_context nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: The study established a reference distribution for a particular pediatric assay. organism: Homo sapiens tissue_or_cell_type: Dried whole-blood thyroglobulin assay experimental_model: Assay-standardization study in 700 iodine-sufficient euthyroid anti-Tg-antibody-negative children aged 5–14 and separate 10-month iodized-salt intervention limitations: Assay-specific pediatric reference distribution; not a universal adult/pregnancy threshold. Anti-Tg-antibody-positive children were excluded from the reference sample; antibody interference and other thyroid diseases remain relevant. exposure: International reference sample and longitudinal measurements before, 5 months and 10 months after salt iodization in deficient children. cross_nutrient: false evidence_location: Primary indexed abstract. [iod-clin-tg2006] Assessment of iodine status using dried blood spot thyroglobulin: development of reference material and establishment of an international reference range in iodine-sufficient children. (2006). https://pubmed.ncbi.nlm.nih.gov/16968789/ DOI: 10.1210/jc.2006-1370

availability_state

biomarker_context Imported condition classification; unverified.

cross_nutrient

false

evidence_location

Primary indexed abstract.

experimental_model

Assay-standardization study in 700 iodine-sufficient euthyroid anti-Tg-antibody-negative children aged 5–14 and separate 10-month iodized-salt intervention

exposure

International reference sample and longitudinal measurements before, 5 months and 10 months after salt iodization in deficient children.

limitations

Assay-specific pediatric reference distribution; not a universal adult/pregnancy threshold. Anti-Tg-antibody-positive children were excluded from the reference sample; antibody interference and other thyroid diseases remain relevant.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

This thyroglobulin assay tracked the population’s response to iodine repletion.

primary_references

[iod-clin-tg2006] Assessment of iodine status using dried blood spot thyroglobulin: development of reference material and establishment of an international reference range in iodine-sufficient children. (2006). https://pubmed.ncbi.nlm.nih.gov/16968789/ DOI: 10.1210/jc.2006-1370

tissue_or_cell_type

Dried whole-blood thyroglobulin assay

trigger_kind

biomarker_context Imported condition classification; unverified.

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1580–1592

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Assay-standardization study in 700 iodine-sufficient euthyroid anti-Tg-antibody-negative children aged 5–14 and separate 10-month iodized-salt intervention · source_derived_draft · unverified_draft

### iod-clin-dbs-tg-response Median dried-blood-spot thyroglobulin fell from 49 to 13 and 8 micrograms/L at 5 and 10 months after iodized salt introduction; proportions above 40 micrograms/L fell from over two thirds to 7% and 3%. Condition category: biomarker_context nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: This thyroglobulin assay tracked the population’s response to iodine repletion. organism: Homo sapiens tissue_or_cell_type: Dried whole-blood thyroglobulin assay experimental_model: Assay-standardization study in 700 iodine-sufficient euthyroid anti-Tg-antibody-negative children aged 5–14 and separate 10-month iodized-salt intervention limitations: Assay-specific pediatric reference distribution; not a universal adult/pregnancy threshold. Anti-Tg-antibody-positive children were excluded from the reference sample; antibody interference and other thyroid diseases remain relevant. exposure: International reference sample and longitudinal measurements before, 5 months and 10 months after salt iodization in deficient children. cross_nutrient: false evidence_location: Primary indexed abstract. [iod-clin-tg2006] Assessment of iodine status using dried blood spot thyroglobulin: development of reference material and establishment of an international reference range in iodine-sufficient children. (2006). https://pubmed.ncbi.nlm.nih.gov/16968789/ DOI: 10.1210/jc.2006-1370

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

true

evidence_location

Primary indexed abstract.

experimental_model

Nine-month randomized double-blind controlled trial in 377 goitrous children aged 6–15 with high anemia prevalence

exposure

Iodized salt 25 micrograms iodine/g versus dual-fortified salt with the same iodine plus 1 mg iron/g as microencapsulated ferrous sulfate; 40-week measurements.

limitations

Clinical intervention and thyroid endpoints do not identify the exact iron-dependent step. Iodized-salt-only participants also improved. Related publications from this cohort are not independent trials. The abstract does not provide the exact between-group thyroxine effect size. The two iron trials have distinct populations and endpoints; their hormone results are not declared a contradiction.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

This iron–iodine trial also found a hormone response.

primary_references

[iod-clin-zimmer2002] Addition of microencapsulated iron to iodized salt improves the efficacy of iodine in goitrous, iron-deficient children: a randomized, double-blind, controlled trial. (2002). https://pubmed.ncbi.nlm.nih.gov/12457449/ DOI: 10.1530/eje.0.1470747

tissue_or_cell_type

Thyroid volume, circulating thyroxine and iron indices

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1244–1256

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Nine-month randomized double-blind controlled trial in 377 goitrous children aged 6–15 with high anemia prevalence · source_derived_draft · unverified_draft

### iod-clin-dual-salt-thyroxine Serum thyroxine was higher with dual-fortified salt than with iodized salt alone (P<0.05), with lower reported hypothyroidism and goiter prevalence (P<0.01). Condition category: nutrient_deficiency nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: This iron–iodine trial also found a hormone response. organism: Homo sapiens tissue_or_cell_type: Thyroid volume, circulating thyroxine and iron indices experimental_model: Nine-month randomized double-blind controlled trial in 377 goitrous children aged 6–15 with high anemia prevalence limitations: Clinical intervention and thyroid endpoints do not identify the exact iron-dependent step. Iodized-salt-only participants also improved. Related publications from this cohort are not independent trials. The abstract does not provide the exact between-group thyroxine effect size. The two iron trials have distinct populations and endpoints; their hormone results are not declared a contradiction. exposure: Iodized salt 25 micrograms iodine/g versus dual-fortified salt with the same iodine plus 1 mg iron/g as microencapsulated ferrous sulfate; 40-week measurements. cross_nutrient: true evidence_location: Primary indexed abstract. [iod-clin-zimmer2002] Addition of microencapsulated iron to iodized salt improves the efficacy of iodine in goitrous, iron-deficient children: a randomized, double-blind, controlled trial. (2002). https://pubmed.ncbi.nlm.nih.gov/12457449/ DOI: 10.1530/eje.0.1470747

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

true

evidence_location

Primary indexed abstract.

experimental_model

Nine-month randomized double-blind controlled trial in 377 goitrous children aged 6–15 with high anemia prevalence

exposure

Iodized salt 25 micrograms iodine/g versus dual-fortified salt with the same iodine plus 1 mg iron/g as microencapsulated ferrous sulfate; 40-week measurements.

limitations

Clinical intervention and thyroid endpoints do not identify the exact iron-dependent step. Iodized-salt-only participants also improved. Related publications from this cohort are not independent trials.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

Adding iron improved the response to the same amount of iodine in this trial.

primary_references

[iod-clin-zimmer2002] Addition of microencapsulated iron to iodized salt improves the efficacy of iodine in goitrous, iron-deficient children: a randomized, double-blind, controlled trial. (2002). https://pubmed.ncbi.nlm.nih.gov/12457449/ DOI: 10.1530/eje.0.1470747

tissue_or_cell_type

Thyroid volume, circulating thyroxine and iron indices

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1230–1242

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Nine-month randomized double-blind controlled trial in 377 goitrous children aged 6–15 with high anemia prevalence · source_derived_draft · unverified_draft

### iod-clin-dual-salt-volume Mean thyroid-volume reduction at 40 weeks was 38% with dual iron–iodine salt versus 18% with iodine-only salt (P<0.01). Condition category: nutrient_deficiency nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: Adding iron improved the response to the same amount of iodine in this trial. organism: Homo sapiens tissue_or_cell_type: Thyroid volume, circulating thyroxine and iron indices experimental_model: Nine-month randomized double-blind controlled trial in 377 goitrous children aged 6–15 with high anemia prevalence limitations: Clinical intervention and thyroid endpoints do not identify the exact iron-dependent step. Iodized-salt-only participants also improved. Related publications from this cohort are not independent trials. exposure: Iodized salt 25 micrograms iodine/g versus dual-fortified salt with the same iodine plus 1 mg iron/g as microencapsulated ferrous sulfate; 40-week measurements. cross_nutrient: true evidence_location: Primary indexed abstract. [iod-clin-zimmer2002] Addition of microencapsulated iron to iodized salt improves the efficacy of iodine in goitrous, iron-deficient children: a randomized, double-blind, controlled trial. (2002). https://pubmed.ncbi.nlm.nih.gov/12457449/ DOI: 10.1530/eje.0.1470747

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

true

evidence_location

Primary indexed abstract.

experimental_model

Randomized double-blind placebo-controlled trial in 166 goitrous iron-deficient children aged 5–14 in Côte d’Ivoire

exposure

All consumed iodized salt providing 10–30 mg iodine/kg salt at household level; iron group received 60 mg elemental Fe/day, four days/week for 16 weeks; outcomes followed to 20 weeks.

limitations

This tests iron treatment on a background of iodine supply. It does not directly measure TPO activity or prove that iron deficiency always prevents iodine response. Specific iron-supplement salt not verified from abstract. The whole-blood thyrotropin assay is identified explicitly; it is not claimed to be the same specimen matrix as serum TSH.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

Improved thyroid size did not mean every hormone measurement changed.

primary_references

[iod-clin-hess2002] Treatment of iron deficiency in goitrous children improves the efficacy of iodized salt in Côte d'Ivoire. (2002). https://pubmed.ncbi.nlm.nih.gov/11916762/ DOI: 10.1093/ajcn/75.4.743

tissue_or_cell_type

Thyroid ultrasound and blood thyroid indices

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1216–1228

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Randomized double-blind placebo-controlled trial in 166 goitrous iron-deficient children aged 5–14 in Côte d’Ivoire · source_derived_draft · unverified_draft

### iod-clin-iron-salt-hormone-null The iron and placebo groups showed no significant difference in serum thyroxine or whole-blood thyrotropin at baseline or during the intervention. Condition category: nutrient_deficiency nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: Improved thyroid size did not mean every hormone measurement changed. organism: Homo sapiens tissue_or_cell_type: Thyroid ultrasound and blood thyroid indices experimental_model: Randomized double-blind placebo-controlled trial in 166 goitrous iron-deficient children aged 5–14 in Côte d’Ivoire limitations: This tests iron treatment on a background of iodine supply. It does not directly measure TPO activity or prove that iron deficiency always prevents iodine response. Specific iron-supplement salt not verified from abstract. The whole-blood thyrotropin assay is identified explicitly; it is not claimed to be the same specimen matrix as serum TSH. exposure: All consumed iodized salt providing 10–30 mg iodine/kg salt at household level; iron group received 60 mg elemental Fe/day, four days/week for 16 weeks; outcomes followed to 20 weeks. cross_nutrient: true evidence_location: Primary indexed abstract. [iod-clin-hess2002] Treatment of iron deficiency in goitrous children improves the efficacy of iodized salt in Côte d'Ivoire. (2002). https://pubmed.ncbi.nlm.nih.gov/11916762/ DOI: 10.1093/ajcn/75.4.743

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

true

evidence_location

Primary indexed abstract.

experimental_model

Randomized double-blind placebo-controlled trial in 166 goitrous iron-deficient children aged 5–14 in Côte d’Ivoire

exposure

All consumed iodized salt providing 10–30 mg iodine/kg salt at household level; iron group received 60 mg elemental Fe/day, four days/week for 16 weeks; outcomes followed to 20 weeks.

limitations

This tests iron treatment on a background of iodine supply. It does not directly measure TPO activity or prove that iron deficiency always prevents iodine response. Specific iron-supplement salt not verified from abstract.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

Correcting iron deficiency improved the thyroid-size response while iodine was supplied.

primary_references

[iod-clin-hess2002] Treatment of iron deficiency in goitrous children improves the efficacy of iodized salt in Côte d'Ivoire. (2002). https://pubmed.ncbi.nlm.nih.gov/11916762/ DOI: 10.1093/ajcn/75.4.743

tissue_or_cell_type

Thyroid ultrasound and blood thyroid indices

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1202–1214

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Randomized double-blind placebo-controlled trial in 166 goitrous iron-deficient children aged 5–14 in Côte d’Ivoire · source_derived_draft · unverified_draft

### iod-clin-iron-salt-volume At 20 weeks, thyroid volume fell 22.8 ± 10.7% with iron treatment versus 12.7 ± 10.1% with placebo in children already using iodized salt (P<0.01). Condition category: nutrient_deficiency nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: Correcting iron deficiency improved the thyroid-size response while iodine was supplied. organism: Homo sapiens tissue_or_cell_type: Thyroid ultrasound and blood thyroid indices experimental_model: Randomized double-blind placebo-controlled trial in 166 goitrous iron-deficient children aged 5–14 in Côte d’Ivoire limitations: This tests iron treatment on a background of iodine supply. It does not directly measure TPO activity or prove that iron deficiency always prevents iodine response. Specific iron-supplement salt not verified from abstract. exposure: All consumed iodized salt providing 10–30 mg iodine/kg salt at household level; iron group received 60 mg elemental Fe/day, four days/week for 16 weeks; outcomes followed to 20 weeks. cross_nutrient: true evidence_location: Primary indexed abstract. [iod-clin-hess2002] Treatment of iron deficiency in goitrous children improves the efficacy of iodized salt in Côte d'Ivoire. (2002). https://pubmed.ncbi.nlm.nih.gov/11916762/ DOI: 10.1093/ajcn/75.4.743

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

false

evidence_location

Primary PDF Methods, trial profile, Results and Table2, pp.197–209.

experimental_model

Double-blind randomized trial in Morocco;241 mother–infant pairs enrolled, 239 randomized after two age exclusions

exposure

Term infants ≤ 8 weeks; indirect arm 121 pairs: mother 400 mg iodine as oral iodized poppyseed oil, infant placebo; direct arm 118 pairs: infant about 100 mg iodine from half a 200 mg oil capsule, mother placebo; follow-up 3, 6, 9 months.

limitations

Both arms received active iodine somewhere in the pair; there was no wholly untreated arm. Breastfeeding and baseline deficiency contextualize the result; measured iodine status is not a child cognitive outcome. Actual infant study dose was about 100 mg, not the 200 mg guideline discussed elsewhere in the paper. No serious adverse events were reported; this does not establish safety for other infant doses, preparations or settings.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

A categorical thyroid outcome improved even though average hormone comparisons were not significant.

primary_references

[iod-clin-bouhouch2014] Direct iodine supplementation of infants versus supplementation of their breastfeeding mothers: a double-blind, randomised, placebo-controlled trial. (2014). https://pubmed.ncbi.nlm.nih.gov/24622750/ DOI: 10.1016/s2213-8587(13)70155-4

tissue_or_cell_type

Breast milk, infant urine and thyroid function

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1566–1578

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Double-blind randomized trial in Morocco;241 mother–infant pairs enrolled, 239 randomized after two age exclusions · source_derived_draft · unverified_draft

### iod-clin-lactation-hypofunction Infant thyroid hypofunction classifications were less frequent with indirect maternal supplementation (P=0.023), although infant TSH and T4 concentrations did not differ significantly between groups over time (P=0.597 and 0.184). Condition category: nutrient_deficiency nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: A categorical thyroid outcome improved even though average hormone comparisons were not significant. organism: Homo sapiens tissue_or_cell_type: Breast milk, infant urine and thyroid function experimental_model: Double-blind randomized trial in Morocco;241 mother–infant pairs enrolled, 239 randomized after two age exclusions limitations: Both arms received active iodine somewhere in the pair; there was no wholly untreated arm. Breastfeeding and baseline deficiency contextualize the result; measured iodine status is not a child cognitive outcome. Actual infant study dose was about 100 mg, not the 200 mg guideline discussed elsewhere in the paper. No serious adverse events were reported; this does not establish safety for other infant doses, preparations or settings. exposure: Term infants ≤ 8 weeks; indirect arm 121 pairs: mother 400 mg iodine as oral iodized poppyseed oil, infant placebo; direct arm 118 pairs: infant about 100 mg iodine from half a 200 mg oil capsule, mother placebo; follow-up 3, 6, 9 months. cross_nutrient: false evidence_location: Primary PDF Methods, trial profile, Results and Table2, pp.197–209. [iod-clin-bouhouch2014] Direct iodine supplementation of infants versus supplementation of their breastfeeding mothers: a double-blind, randomised, placebo-controlled trial. (2014). https://pubmed.ncbi.nlm.nih.gov/24622750/ DOI: 10.1016/s2213-8587(13)70155-4

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

false

evidence_location

Primary PDF Methods, trial profile, Results and Table2, pp.197–209.

experimental_model

Double-blind randomized trial in Morocco;241 mother–infant pairs enrolled, 239 randomized after two age exclusions

exposure

Term infants ≤ 8 weeks; indirect arm 121 pairs: mother 400 mg iodine as oral iodized poppyseed oil, infant placebo; direct arm 118 pairs: infant about 100 mg iodine from half a 200 mg oil capsule, mother placebo; follow-up 3, 6, 9 months.

limitations

Both arms received active iodine somewhere in the pair; there was no wholly untreated arm. Breastfeeding and baseline deficiency contextualize the result; measured iodine status is not a child cognitive outcome. Actual infant study dose was about 100 mg, not the 200 mg guideline discussed elsewhere in the paper. The 100-microgram/L statement concerns group medians as interpreted by the paper, not proof of adequacy in every infant.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

The maternal route improved the infants’ measured iodine status for longer.

primary_references

[iod-clin-bouhouch2014] Direct iodine supplementation of infants versus supplementation of their breastfeeding mothers: a double-blind, randomised, placebo-controlled trial. (2014). https://pubmed.ncbi.nlm.nih.gov/24622750/ DOI: 10.1016/s2213-8587(13)70155-4

tissue_or_cell_type

Breast milk, infant urine and thyroid function

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1552–1564

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Double-blind randomized trial in Morocco;241 mother–infant pairs enrolled, 239 randomized after two age exclusions · source_derived_draft · unverified_draft

### iod-clin-lactation-infant-urine Infant urinary iodine was higher in the maternal-supplement arm (P=0.042); group medians exceeded 100 micrograms/L at 3 and 6 months in that arm, versus only 6 months in the direct-infant arm. Condition category: nutrient_deficiency nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: The maternal route improved the infants’ measured iodine status for longer. organism: Homo sapiens tissue_or_cell_type: Breast milk, infant urine and thyroid function experimental_model: Double-blind randomized trial in Morocco;241 mother–infant pairs enrolled, 239 randomized after two age exclusions limitations: Both arms received active iodine somewhere in the pair; there was no wholly untreated arm. Breastfeeding and baseline deficiency contextualize the result; measured iodine status is not a child cognitive outcome. Actual infant study dose was about 100 mg, not the 200 mg guideline discussed elsewhere in the paper. The 100-microgram/L statement concerns group medians as interpreted by the paper, not proof of adequacy in every infant. exposure: Term infants ≤ 8 weeks; indirect arm 121 pairs: mother 400 mg iodine as oral iodized poppyseed oil, infant placebo; direct arm 118 pairs: infant about 100 mg iodine from half a 200 mg oil capsule, mother placebo; follow-up 3, 6, 9 months. cross_nutrient: false evidence_location: Primary PDF Methods, trial profile, Results and Table2, pp.197–209. [iod-clin-bouhouch2014] Direct iodine supplementation of infants versus supplementation of their breastfeeding mothers: a double-blind, randomised, placebo-controlled trial. (2014). https://pubmed.ncbi.nlm.nih.gov/24622750/ DOI: 10.1016/s2213-8587(13)70155-4

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

false

evidence_location

Primary PDF Methods, trial profile, Results and Table2, pp.197–209.

experimental_model

Double-blind randomized trial in Morocco;241 mother–infant pairs enrolled, 239 randomized after two age exclusions

exposure

Term infants ≤ 8 weeks; indirect arm 121 pairs: mother 400 mg iodine as oral iodized poppyseed oil, infant placebo; direct arm 118 pairs: infant about 100 mg iodine from half a 200 mg oil capsule, mother placebo; follow-up 3, 6, 9 months.

limitations

Both arms received active iodine somewhere in the pair; there was no wholly untreated arm. Breastfeeding and baseline deficiency contextualize the result; measured iodine status is not a child cognitive outcome. Actual infant study dose was about 100 mg, not the 200 mg guideline discussed elsewhere in the paper.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

Treating the mother increased the iodine delivered in her milk in this deficient setting.

primary_references

[iod-clin-bouhouch2014] Direct iodine supplementation of infants versus supplementation of their breastfeeding mothers: a double-blind, randomised, placebo-controlled trial. (2014). https://pubmed.ncbi.nlm.nih.gov/24622750/ DOI: 10.1016/s2213-8587(13)70155-4

tissue_or_cell_type

Breast milk, infant urine and thyroid function

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1538–1550

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Double-blind randomized trial in Morocco;241 mother–infant pairs enrolled, 239 randomized after two age exclusions · source_derived_draft · unverified_draft

### iod-clin-lactation-milk Breast-milk iodine concentration was higher with maternal supplementation than with direct infant supplementation over follow-up (P<0.0001). Condition category: nutrient_deficiency nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: Treating the mother increased the iodine delivered in her milk in this deficient setting. organism: Homo sapiens tissue_or_cell_type: Breast milk, infant urine and thyroid function experimental_model: Double-blind randomized trial in Morocco;241 mother–infant pairs enrolled, 239 randomized after two age exclusions limitations: Both arms received active iodine somewhere in the pair; there was no wholly untreated arm. Breastfeeding and baseline deficiency contextualize the result; measured iodine status is not a child cognitive outcome. Actual infant study dose was about 100 mg, not the 200 mg guideline discussed elsewhere in the paper. exposure: Term infants ≤ 8 weeks; indirect arm 121 pairs: mother 400 mg iodine as oral iodized poppyseed oil, infant placebo; direct arm 118 pairs: infant about 100 mg iodine from half a 200 mg oil capsule, mother placebo; follow-up 3, 6, 9 months. cross_nutrient: false evidence_location: Primary PDF Methods, trial profile, Results and Table2, pp.197–209. [iod-clin-bouhouch2014] Direct iodine supplementation of infants versus supplementation of their breastfeeding mothers: a double-blind, randomised, placebo-controlled trial. (2014). https://pubmed.ncbi.nlm.nih.gov/24622750/ DOI: 10.1016/s2213-8587(13)70155-4

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

false

evidence_location

Primary PDF Methods p.69, Results and Fig2 pp.70–71; relevant pages visually inspected because OCR is imperfect.

experimental_model

Historical double-blind controlled maternal iodinated-oil trial begun 1966, with children born 1966–1972 followed through 1982 in five selected Papua New Guinea villages

exposure

Intramuscular iodinated oil versus saline; comparison by conception before/after maternal trial entry. The follow-up paper does not verify the injection dose in the inspected methods.

limitations

Long-term follow-up was restricted for logistical reasons to five of 13 original villages with high disease prevalence. Historical syndrome criteria and selection differ from modern mild-deficiency trials. Do not assume all developmental disorders were prevented or that established deficits were reversed. Two possible cases remained among the 237 treated-group children. Three definite treated-group cases in the overall 274 children had maternal treatment only at 30, 32 or 34 weeks gestation; this does not establish an exact universal gestational cutoff.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

In severe deficiency, supplying iodine before conception prevented the study-defined definite neurological syndrome in this follow-up.

primary_references

[iod-clin-pharoah1987] A controlled trial of iodinated oil for the prevention of endemic cretinism: a long-term follow-up. (1987). https://pubmed.ncbi.nlm.nih.gov/3032814/ DOI: 10.1093/ije/16.1.68

tissue_or_cell_type

Child neurological, hearing/speech and motor outcomes

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1412–1424

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Historical double-blind controlled maternal iodinated-oil trial begun 1966, with children born 1966–1972 followed through 1982 in five selected Papua New Guinea villages · source_derived_draft · unverified_draft

### iod-clin-preconception-neurology Among children conceived after maternal trial entry, the follow-up classified 0 of 237 in the iodinated-oil group and 14 of 215 in the saline group as definite cases of the historical neurological iodine-deficiency syndrome. Condition category: nutrient_deficiency nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: In severe deficiency, supplying iodine before conception prevented the study-defined definite neurological syndrome in this follow-up. organism: Homo sapiens tissue_or_cell_type: Child neurological, hearing/speech and motor outcomes experimental_model: Historical double-blind controlled maternal iodinated-oil trial begun 1966, with children born 1966–1972 followed through 1982 in five selected Papua New Guinea villages limitations: Long-term follow-up was restricted for logistical reasons to five of 13 original villages with high disease prevalence. Historical syndrome criteria and selection differ from modern mild-deficiency trials. Do not assume all developmental disorders were prevented or that established deficits were reversed. Two possible cases remained among the 237 treated-group children. Three definite treated-group cases in the overall 274 children had maternal treatment only at 30, 32 or 34 weeks gestation; this does not establish an exact universal gestational cutoff. exposure: Intramuscular iodinated oil versus saline; comparison by conception before/after maternal trial entry. The follow-up paper does not verify the injection dose in the inspected methods. cross_nutrient: false evidence_location: Primary PDF Methods p.69, Results and Fig2 pp.70–71; relevant pages visually inspected because OCR is imperfect. [iod-clin-pharoah1987] A controlled trial of iodinated oil for the prevention of endemic cretinism: a long-term follow-up. (1987). https://pubmed.ncbi.nlm.nih.gov/3032814/ DOI: 10.1093/ije/16.1.68

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

false

evidence_location

Primary full PDF Methods; Table2 and Fig2; Discussion, pp.853–863.

experimental_model

Randomized double-blind placebo-controlled maternal trial in Bangkok and Bangalore; 832 women randomized, 313 children assessed for IQ and 315 for executive function at age 5–6

exposure

200 micrograms iodine/day as potassium iodide until delivery; mean enrollment 10.7 weeks gestation; baseline median urinary iodine 131 micrograms/L; IQ iodine 159/placebo 154, executive function 159/156.

limitations

Mild group-level deficiency with site differences: Thailand deficient and India at low adequacy. Substantial attrition was balanced between groups; measured baseline characteristics were similar in those followed and lost. This does not test preconception treatment or severe deficiency. Reported differences, CIs and mixed-model P values are retained as published.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

Executive-function scores did not significantly differ between the trial groups.

primary_references

[iod-clin-gow2017] Effect of iodine supplementation in pregnant women on child neurodevelopment: a randomised, double-blind, placebo-controlled trial. (2017). https://pubmed.ncbi.nlm.nih.gov/29030199/ DOI: 10.1016/s2213-8587(17)30332-7

tissue_or_cell_type

Maternal iodine status and child neurodevelopment

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1398–1410

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Randomized double-blind placebo-controlled maternal trial in Bangkok and Bangalore; 832 women randomized, 313 children assessed for IQ and 315 for executive function at age 5–6 · source_derived_draft · unverified_draft

### iod-clin-pregnancy-executive The BRIEF-P global executive score averaged 90.6 versus 91.5; reported difference −0.9 (95% CI −6.8 to 5.0), P=0.74. Condition category: nutrient_deficiency nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: Executive-function scores did not significantly differ between the trial groups. organism: Homo sapiens tissue_or_cell_type: Maternal iodine status and child neurodevelopment experimental_model: Randomized double-blind placebo-controlled maternal trial in Bangkok and Bangalore; 832 women randomized, 313 children assessed for IQ and 315 for executive function at age 5–6 limitations: Mild group-level deficiency with site differences: Thailand deficient and India at low adequacy. Substantial attrition was balanced between groups; measured baseline characteristics were similar in those followed and lost. This does not test preconception treatment or severe deficiency. Reported differences, CIs and mixed-model P values are retained as published. exposure: 200 micrograms iodine/day as potassium iodide until delivery; mean enrollment 10.7 weeks gestation; baseline median urinary iodine 131 micrograms/L; IQ iodine 159/placebo 154, executive function 159/156. cross_nutrient: false evidence_location: Primary full PDF Methods; Table2 and Fig2; Discussion, pp.853–863. [iod-clin-gow2017] Effect of iodine supplementation in pregnant women on child neurodevelopment: a randomised, double-blind, placebo-controlled trial. (2017). https://pubmed.ncbi.nlm.nih.gov/29030199/ DOI: 10.1016/s2213-8587(17)30332-7

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

false

evidence_location

Primary full PDF Methods; Table2 and Fig2; Discussion, pp.853–863.

experimental_model

Randomized double-blind placebo-controlled maternal trial in Bangkok and Bangalore; 832 women randomized, 313 children assessed for IQ and 315 for executive function at age 5–6

exposure

200 micrograms iodine/day as potassium iodide until delivery; mean enrollment 10.7 weeks gestation; baseline median urinary iodine 131 micrograms/L; IQ iodine 159/placebo 154, executive function 159/156.

limitations

Mild group-level deficiency with site differences: Thailand deficient and India at low adequacy. Substantial attrition was balanced between groups; measured baseline characteristics were similar in those followed and lost. This does not test preconception treatment or severe deficiency. Reported differences, CIs and mixed-model P values are retained as published.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

The performance-IQ endpoint also showed no significant improvement.

primary_references

[iod-clin-gow2017] Effect of iodine supplementation in pregnant women on child neurodevelopment: a randomised, double-blind, placebo-controlled trial. (2017). https://pubmed.ncbi.nlm.nih.gov/29030199/ DOI: 10.1016/s2213-8587(17)30332-7

tissue_or_cell_type

Maternal iodine status and child neurodevelopment

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1384–1396

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Randomized double-blind placebo-controlled maternal trial in Bangkok and Bangalore; 832 women randomized, 313 children assessed for IQ and 315 for executive function at age 5–6 · source_derived_draft · unverified_draft

### iod-clin-pregnancy-performance Performance IQ averaged 97.5 versus 99.1; reported iodine-minus-placebo difference −1.6 (95% CI −4.5 to 1.3), P=0.44. Condition category: nutrient_deficiency nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: The performance-IQ endpoint also showed no significant improvement. organism: Homo sapiens tissue_or_cell_type: Maternal iodine status and child neurodevelopment experimental_model: Randomized double-blind placebo-controlled maternal trial in Bangkok and Bangalore; 832 women randomized, 313 children assessed for IQ and 315 for executive function at age 5–6 limitations: Mild group-level deficiency with site differences: Thailand deficient and India at low adequacy. Substantial attrition was balanced between groups; measured baseline characteristics were similar in those followed and lost. This does not test preconception treatment or severe deficiency. Reported differences, CIs and mixed-model P values are retained as published. exposure: 200 micrograms iodine/day as potassium iodide until delivery; mean enrollment 10.7 weeks gestation; baseline median urinary iodine 131 micrograms/L; IQ iodine 159/placebo 154, executive function 159/156. cross_nutrient: false evidence_location: Primary full PDF Methods; Table2 and Fig2; Discussion, pp.853–863. [iod-clin-gow2017] Effect of iodine supplementation in pregnant women on child neurodevelopment: a randomised, double-blind, placebo-controlled trial. (2017). https://pubmed.ncbi.nlm.nih.gov/29030199/ DOI: 10.1016/s2213-8587(17)30332-7

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

false

evidence_location

Primary full PDF Methods; Table2 and Fig2; Discussion, pp.853–863.

experimental_model

Randomized double-blind placebo-controlled maternal trial in Bangkok and Bangalore; 832 women randomized, 313 children assessed for IQ and 315 for executive function at age 5–6

exposure

200 micrograms iodine/day as potassium iodide until delivery; mean enrollment 10.7 weeks gestation; baseline median urinary iodine 131 micrograms/L; IQ iodine 159/placebo 154, executive function 159/156.

limitations

Mild group-level deficiency with site differences: Thailand deficient and India at low adequacy. Substantial attrition was balanced between groups; measured baseline characteristics were similar in those followed and lost. This does not test preconception treatment or severe deficiency. Reported differences, CIs and mixed-model P values are retained as published.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

Starting iodine during this mildly deficient pregnancy trial did not significantly improve verbal IQ.

primary_references

[iod-clin-gow2017] Effect of iodine supplementation in pregnant women on child neurodevelopment: a randomised, double-blind, placebo-controlled trial. (2017). https://pubmed.ncbi.nlm.nih.gov/29030199/ DOI: 10.1016/s2213-8587(17)30332-7

tissue_or_cell_type

Maternal iodine status and child neurodevelopment

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1370–1382

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Randomized double-blind placebo-controlled maternal trial in Bangkok and Bangalore; 832 women randomized, 313 children assessed for IQ and 315 for executive function at age 5–6 · source_derived_draft · unverified_draft

### iod-clin-pregnancy-verbal Verbal IQ at 5–6 years averaged 89.5 versus 90.2 with maternal iodine versus placebo; reported difference −0.7 (95% CI −2.9 to 1.5), P=0.77. Condition category: nutrient_deficiency nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: Starting iodine during this mildly deficient pregnancy trial did not significantly improve verbal IQ. organism: Homo sapiens tissue_or_cell_type: Maternal iodine status and child neurodevelopment experimental_model: Randomized double-blind placebo-controlled maternal trial in Bangkok and Bangalore; 832 women randomized, 313 children assessed for IQ and 315 for executive function at age 5–6 limitations: Mild group-level deficiency with site differences: Thailand deficient and India at low adequacy. Substantial attrition was balanced between groups; measured baseline characteristics were similar in those followed and lost. This does not test preconception treatment or severe deficiency. Reported differences, CIs and mixed-model P values are retained as published. exposure: 200 micrograms iodine/day as potassium iodide until delivery; mean enrollment 10.7 weeks gestation; baseline median urinary iodine 131 micrograms/L; IQ iodine 159/placebo 154, executive function 159/156. cross_nutrient: false evidence_location: Primary full PDF Methods; Table2 and Fig2; Discussion, pp.853–863. [iod-clin-gow2017] Effect of iodine supplementation in pregnant women on child neurodevelopment: a randomised, double-blind, placebo-controlled trial. (2017). https://pubmed.ncbi.nlm.nih.gov/29030199/ DOI: 10.1016/s2213-8587(17)30332-7

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

true

evidence_location

Primary indexed abstract.

experimental_model

Placebo-controlled selenium intervention in 52 schoolchildren from a region of severe iodine and selenium deficiency in northern Zaire

exposure

Selenium 50 micrograms/day as selenomethionine or placebo for two months; no concurrent iodine-repletion regimen reported in the abstract.

limitations

The abstract reports before/after changes in the selenium group; do not mistake these for adjusted between-group estimates. DIO1 restoration was a proposed explanation, not directly measured. Hormone changes do not themselves establish symptomatic deterioration or a universal order for supplement treatment.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

The free T4 measurement also fell after selenium was added.

primary_references

[iod-clin-contempre1992] Effect of selenium supplementation on thyroid hormone metabolism in an iodine and selenium deficient population. (1992). https://pubmed.ncbi.nlm.nih.gov/1424183/ DOI: 10.1111/j.1365-2265.1992.tb02268.x

tissue_or_cell_type

Serum thyroid-hormone concentrations

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1272–1284

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Placebo-controlled selenium intervention in 52 schoolchildren from a region of severe iodine and selenium deficiency in northern Zaire · source_derived_draft · unverified_draft

### iod-clin-selenium-free-t4 Mean serum free T4 fell from 11.8 ± 6.7 to 8.4 ± 4.1 pmol/L after selenium treatment (P<0.01). Condition category: nutrient_deficiency nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: The free T4 measurement also fell after selenium was added. organism: Homo sapiens tissue_or_cell_type: Serum thyroid-hormone concentrations experimental_model: Placebo-controlled selenium intervention in 52 schoolchildren from a region of severe iodine and selenium deficiency in northern Zaire limitations: The abstract reports before/after changes in the selenium group; do not mistake these for adjusted between-group estimates. DIO1 restoration was a proposed explanation, not directly measured. Hormone changes do not themselves establish symptomatic deterioration or a universal order for supplement treatment. exposure: Selenium 50 micrograms/day as selenomethionine or placebo for two months; no concurrent iodine-repletion regimen reported in the abstract. cross_nutrient: true evidence_location: Primary indexed abstract. [iod-clin-contempre1992] Effect of selenium supplementation on thyroid hormone metabolism in an iodine and selenium deficient population. (1992). https://pubmed.ncbi.nlm.nih.gov/1424183/ DOI: 10.1111/j.1365-2265.1992.tb02268.x

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

true

evidence_location

Primary indexed abstract.

experimental_model

Placebo-controlled selenium intervention in 52 schoolchildren from a region of severe iodine and selenium deficiency in northern Zaire

exposure

Selenium 50 micrograms/day as selenomethionine or placebo for two months; no concurrent iodine-repletion regimen reported in the abstract.

limitations

The abstract reports before/after changes in the selenium group; do not mistake these for adjusted between-group estimates. DIO1 restoration was a proposed explanation, not directly measured. Hormone changes do not themselves establish symptomatic deterioration or a universal order for supplement treatment.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

The hormone pattern changed unevenly; T3 and TSH did not simply rise with selenium.

primary_references

[iod-clin-contempre1992] Effect of selenium supplementation on thyroid hormone metabolism in an iodine and selenium deficient population. (1992). https://pubmed.ncbi.nlm.nih.gov/1424183/ DOI: 10.1111/j.1365-2265.1992.tb02268.x

tissue_or_cell_type

Serum thyroid-hormone concentrations

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1286–1298

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Placebo-controlled selenium intervention in 52 schoolchildren from a region of severe iodine and selenium deficiency in northern Zaire · source_derived_draft · unverified_draft

### iod-clin-selenium-rt3 Mean reverse T3 fell from 124 ± 115 to 90 ± 72 pmol/L after selenium treatment (P<0.05), while serum T3 and TSH did not change significantly. Condition category: nutrient_deficiency nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: The hormone pattern changed unevenly; T3 and TSH did not simply rise with selenium. organism: Homo sapiens tissue_or_cell_type: Serum thyroid-hormone concentrations experimental_model: Placebo-controlled selenium intervention in 52 schoolchildren from a region of severe iodine and selenium deficiency in northern Zaire limitations: The abstract reports before/after changes in the selenium group; do not mistake these for adjusted between-group estimates. DIO1 restoration was a proposed explanation, not directly measured. Hormone changes do not themselves establish symptomatic deterioration or a universal order for supplement treatment. exposure: Selenium 50 micrograms/day as selenomethionine or placebo for two months; no concurrent iodine-repletion regimen reported in the abstract. cross_nutrient: true evidence_location: Primary indexed abstract. [iod-clin-contempre1992] Effect of selenium supplementation on thyroid hormone metabolism in an iodine and selenium deficient population. (1992). https://pubmed.ncbi.nlm.nih.gov/1424183/ DOI: 10.1111/j.1365-2265.1992.tb02268.x

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

true

evidence_location

Primary indexed abstract.

experimental_model

Placebo-controlled selenium intervention in 52 schoolchildren from a region of severe iodine and selenium deficiency in northern Zaire

exposure

Selenium 50 micrograms/day as selenomethionine or placebo for two months; no concurrent iodine-repletion regimen reported in the abstract.

limitations

The abstract reports before/after changes in the selenium group; do not mistake these for adjusted between-group estimates. DIO1 restoration was a proposed explanation, not directly measured. Hormone changes do not themselves establish symptomatic deterioration or a universal order for supplement treatment.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

Selenium alone lowered circulating T4 in this co-deficient population.

primary_references

[iod-clin-contempre1992] Effect of selenium supplementation on thyroid hormone metabolism in an iodine and selenium deficient population. (1992). https://pubmed.ncbi.nlm.nih.gov/1424183/ DOI: 10.1111/j.1365-2265.1992.tb02268.x

tissue_or_cell_type

Serum thyroid-hormone concentrations

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1258–1270

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Placebo-controlled selenium intervention in 52 schoolchildren from a region of severe iodine and selenium deficiency in northern Zaire · source_derived_draft · unverified_draft

### iod-clin-selenium-total-t4 Mean serum total T4 fell from 73.1 ± 45.4 to 48.3 ± 23.7 nmol/L after two months of selenium treatment (P<0.001) in the iodine/selenium-deficient setting. Condition category: nutrient_deficiency nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: Selenium alone lowered circulating T4 in this co-deficient population. organism: Homo sapiens tissue_or_cell_type: Serum thyroid-hormone concentrations experimental_model: Placebo-controlled selenium intervention in 52 schoolchildren from a region of severe iodine and selenium deficiency in northern Zaire limitations: The abstract reports before/after changes in the selenium group; do not mistake these for adjusted between-group estimates. DIO1 restoration was a proposed explanation, not directly measured. Hormone changes do not themselves establish symptomatic deterioration or a universal order for supplement treatment. exposure: Selenium 50 micrograms/day as selenomethionine or placebo for two months; no concurrent iodine-repletion regimen reported in the abstract. cross_nutrient: true evidence_location: Primary indexed abstract. [iod-clin-contempre1992] Effect of selenium supplementation on thyroid hormone metabolism in an iodine and selenium deficient population. (1992). https://pubmed.ncbi.nlm.nih.gov/1424183/ DOI: 10.1111/j.1365-2265.1992.tb02268.x

availability_state

biomarker_context Imported condition classification; unverified.

cross_nutrient

false

evidence_location

Primary indexed abstract.

experimental_model

Prospective 15-month repeated-collection study in 22 healthy Swiss women aged 52–77

exposure

341 24-hour urine collections and 177 corresponding fasting second-void morning spot samples; within-person variability used for precision estimates.

limitations

The sample-number estimate is specific to this population, sampling method and 20% precision target. It is not a universal instruction to collect ten specimens or a validated single-person diagnostic cutoff.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

The precision calculation required repeated samples, not a single diagnostic urine value.

primary_references

[iod-clin-konig2011] Ten repeat collections for urinary iodine from spot samples or 24-hour samples are needed to reliably estimate individual iodine status in women. (2011). https://pubmed.ncbi.nlm.nih.gov/21918061/ DOI: 10.3945/jn.111.144071

tissue_or_cell_type

Spot and24-hour urine

trigger_kind

biomarker_context Imported condition classification; unverified.

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1440–1452

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Prospective 15-month repeated-collection study in 22 healthy Swiss women aged 52–77 · source_derived_draft · unverified_draft

### iod-clin-urine-precision The study estimated that 10 spot or 24-hour collections were needed to estimate individual iodine status with 20% precision in these women. Condition category: biomarker_context nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: The precision calculation required repeated samples, not a single diagnostic urine value. organism: Homo sapiens tissue_or_cell_type: Spot and24-hour urine experimental_model: Prospective 15-month repeated-collection study in 22 healthy Swiss women aged 52–77 limitations: The sample-number estimate is specific to this population, sampling method and 20% precision target. It is not a universal instruction to collect ten specimens or a validated single-person diagnostic cutoff. exposure: 341 24-hour urine collections and 177 corresponding fasting second-void morning spot samples; within-person variability used for precision estimates. cross_nutrient: false evidence_location: Primary indexed abstract. [iod-clin-konig2011] Ten repeat collections for urinary iodine from spot samples or 24-hour samples are needed to reliably estimate individual iodine status in women. (2011). https://pubmed.ncbi.nlm.nih.gov/21918061/ DOI: 10.3945/jn.111.144071

availability_state

biomarker_context Imported condition classification; unverified.

cross_nutrient

false

evidence_location

Primary indexed abstract.

experimental_model

Prospective 15-month repeated-collection study in 22 healthy Swiss women aged 52–77

exposure

341 24-hour urine collections and 177 corresponding fasting second-void morning spot samples; within-person variability used for precision estimates.

limitations

The sample-number estimate is specific to this population, sampling method and 20% precision target. It is not a universal instruction to collect ten specimens or a validated single-person diagnostic cutoff.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

One urine result can vary substantially within the same person.

primary_references

[iod-clin-konig2011] Ten repeat collections for urinary iodine from spot samples or 24-hour samples are needed to reliably estimate individual iodine status in women. (2011). https://pubmed.ncbi.nlm.nih.gov/21918061/ DOI: 10.3945/jn.111.144071

tissue_or_cell_type

Spot and24-hour urine

trigger_kind

biomarker_context Imported condition classification; unverified.

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1426–1438

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Prospective 15-month repeated-collection study in 22 healthy Swiss women aged 52–77 · source_derived_draft · unverified_draft

### iod-clin-urine-variability Mean within-person variability was 32% for measured 24-hour iodine excretion, 33% for estimated 24-hour excretion and 38% for spot urinary iodine concentration. Condition category: biomarker_context nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: One urine result can vary substantially within the same person. organism: Homo sapiens tissue_or_cell_type: Spot and24-hour urine experimental_model: Prospective 15-month repeated-collection study in 22 healthy Swiss women aged 52–77 limitations: The sample-number estimate is specific to this population, sampling method and 20% precision target. It is not a universal instruction to collect ten specimens or a validated single-person diagnostic cutoff. exposure: 341 24-hour urine collections and 177 corresponding fasting second-void morning spot samples; within-person variability used for precision estimates. cross_nutrient: false evidence_location: Primary indexed abstract. [iod-clin-konig2011] Ten repeat collections for urinary iodine from spot samples or 24-hour samples are needed to reliably estimate individual iodine status in women. (2011). https://pubmed.ncbi.nlm.nih.gov/21918061/ DOI: 10.3945/jn.111.144071

evidence_span

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experimental_model

Sixteen men given oral T3 before, during and after 80 cold air exposures, with and without T3 replacement

exposure

Eighty exposures to 4 degrees C air, ten per week

limitations

Cold air rather than water immersion, recorded because it isolates the thyroid hormone kinetics. The pharmacological oral T3 dose is not physiological.

nutrient_topic

Cold water immersion research collection; topical membership is not evidence of a direct clinical effect, and a therapeutic exposure is not a dietary intake. · Cold water immersion

organism

Human

plain_language

Cold makes the body consume active thyroid hormone faster, independently of the usual feedback loop.

primary_references

[cold-p1636702] Multiple cold air exposures change oral triiodothyronine kinetics in normal men. (1992). https://pubmed.ncbi.nlm.nih.gov/1636702/ DOI: 10.1152/ajpendo.1992.263.1.e85

tissue_or_cell_type

Whole body thyroid hormone kinetics

Cold water immersion: cold sensing, heat production, the catecholamine axis and what repeated exposure changes (2026-09-19) · lines 676–687

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Sixteen men given oral T3 before, during and after 80 cold air exposures, with and without T3 replacement · source_derived_draft · unverified_draft

### cold-cold-t3-clearance Repeated cold air exposure increased the oral metabolic clearance rate of T3 by 5.4 l/day/m2 and the disposal rate by 10.2 nmol/day/m2, and these increases were not dependent on thyrotropin or thyroxine, since they were unchanged in men given replacement T3 whose TSH and T4 fell by about half. Condition category: normal nutrient_topic: Cold water immersion research collection; topical membership is not evidence of a direct clinical effect, and a therapeutic exposure is not a dietary intake. plain_language: Cold makes the body consume active thyroid hormone faster, independently of the usual feedback loop. organism: Human tissue_or_cell_type: Whole body thyroid hormone kinetics experimental_model: Sixteen men given oral T3 before, during and after 80 cold air exposures, with and without T3 replacement limitations: Cold air rather than water immersion, recorded because it isolates the thyroid hormone kinetics. The pharmacological oral T3 dose is not physiological. exposure: Eighty exposures to 4 degrees C air, ten per week evidence_span: {"source_cache": "artifacts/cold-research/1636702.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "4e0d8127d3ebb682588afd84b635d2607dce9ebec4e7573d25e7baae58fc9301", "start_char": 0, "end_char": 1183, "text_sha256": "4e0d8127d3ebb682588afd84b635d2607dce9ebec4e7573d25e7baae58fc9301"} [cold-p1636702] Multiple cold air exposures change oral triiodothyronine kinetics in normal men. (1992). https://pubmed.ncbi.nlm.nih.gov/1636702/ DOI: 10.1152/ajpendo.1992.263.1.e85

evidence_span

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experimental_model

Mice with targeted disruption of the Dio2 gene, with brown adipocyte assays and T3 rescue

exposure

Cold stress, with norepinephrine, CL316,243 or forskolin stimulation, and a single T3 injection

limitations

The selenoenzyme is the link between thyroid hormone and sympathetic signalling. Plasma T3 was normal in the knockouts, so the defect is local hormone generation, not circulating hormone.

nutrient_topic

Cold water immersion research collection; topical membership is not evidence of a direct clinical effect, and a therapeutic exposure is not a dietary intake. · Cold water immersion

organism

Mouse

plain_language

Cold makes brown fat build a selenium enzyme that manufactures active thyroid hormone on the spot.

primary_references

[cold-p11696583] The type 2 iodothyronine deiodinase is essential for adaptive thermogenesis in brown adipose tissue. (2001). https://pubmed.ncbi.nlm.nih.gov/11696583/ DOI: 10.1172/jci13803

tissue_or_cell_type

Brown adipose tissue

Cold water immersion: cold sensing, heat production, the catecholamine axis and what repeated exposure changes (2026-09-19) · lines 377–388

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Mice with targeted disruption of the Dio2 gene, with brown adipocyte assays and T3 rescue · source_derived_draft · unverified_draft

### cold-dio2-selenoenzyme Type 2 iodothyronine deiodinase is a selenoenzyme, the product of the cAMP-dependent Dio2 gene, which increases 10- to 50-fold during cold stress only in brown adipose tissue. Condition category: normal nutrient_topic: Cold water immersion research collection; topical membership is not evidence of a direct clinical effect, and a therapeutic exposure is not a dietary intake. plain_language: Cold makes brown fat build a selenium enzyme that manufactures active thyroid hormone on the spot. organism: Mouse tissue_or_cell_type: Brown adipose tissue experimental_model: Mice with targeted disruption of the Dio2 gene, with brown adipocyte assays and T3 rescue limitations: The selenoenzyme is the link between thyroid hormone and sympathetic signalling. Plasma T3 was normal in the knockouts, so the defect is local hormone generation, not circulating hormone. exposure: Cold stress, with norepinephrine, CL316,243 or forskolin stimulation, and a single T3 injection evidence_span: {"source_cache": "artifacts/cold-research/11696583.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "adbd82ff8c43d8a2718cfa752c9a0607c367648d6573b968eb885c883376dc68", "start_char": 0, "end_char": 1332, "text_sha256": "adbd82ff8c43d8a2718cfa752c9a0607c367648d6573b968eb885c883376dc68"} [cold-p11696583] The type 2 iodothyronine deiodinase is essential for adaptive thermogenesis in brown adipose tissue. (2001). https://pubmed.ncbi.nlm.nih.gov/11696583/ DOI: 10.1172/jci13803

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

Vitamin A/iodine -> thyroid feedback.

experimental_model

404 children; factorial trial.

limitations

TSH-beta transcriptional suppression is an explanation, not a directly measured step in these children.

nutrient_topic

Vitamin A research collection; topical membership is not evidence of a direct dietary effect. · Vitamin A

organism

Homo sapiens

plain_language

Vitamin A status affected how strongly the thyroid was being stimulated.

primary_references

[va-zimmermann2007-iodine] Vitamin A supplementation in iodine-deficient African children decreases thyrotropin stimulation of the thyroid and reduces the goiter rate (2007). https://pubmed.ncbi.nlm.nih.gov/17921382/ DOI: 10.1093/ajcn/86.4.1040

tissue_or_cell_type

Pituitary-thyroid axis

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1578–1588

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · 404 children; factorial trial. · source_derived_draft · unverified_draft

### va-iodine-context-lowers-tsh Vitamin A without iodine supplementation lowered TSH in the iodine-deficient study setting. Condition category: nutrient_deficiency nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Vitamin A status affected how strongly the thyroid was being stimulated. organism: Homo sapiens tissue_or_cell_type: Pituitary-thyroid axis experimental_model: 404 children; factorial trial. limitations: TSH-beta transcriptional suppression is an explanation, not a directly measured step in these children. cross_nutrient: Vitamin A/iodine -> thyroid feedback. [va-zimmermann2007-iodine] Vitamin A supplementation in iodine-deficient African children decreases thyrotropin stimulation of the thyroid and reduces the goiter rate (2007). https://pubmed.ncbi.nlm.nih.gov/17921382/ DOI: 10.1093/ajcn/86.4.1040

availability_state

nutrient_deficiency Imported condition classification; unverified.

experimental_model

Same trial.

limitations

Iodine treatment remained effective; nutrient roles are not interchangeable.

nutrient_topic

Vitamin A research collection; topical membership is not evidence of a direct dietary effect. · Vitamin A

organism

Homo sapiens

plain_language

Reduced thyroid enlargement did not establish a universal rise in thyroid hormone.

primary_references

[va-zimmermann2007-iodine] Vitamin A supplementation in iodine-deficient African children decreases thyrotropin stimulation of the thyroid and reduces the goiter rate (2007). https://pubmed.ncbi.nlm.nih.gov/17921382/ DOI: 10.1093/ajcn/86.4.1040

tissue_or_cell_type

Thyroid

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1590–1599

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Same trial. · source_derived_draft · unverified_draft

### va-iodine-context-thyroid-volume Thyroid volume and thyroglobulin decreased with vitamin A alone; total T4 showed no significant treatment-interaction effect. Condition category: nutrient_deficiency nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Reduced thyroid enlargement did not establish a universal rise in thyroid hormone. organism: Homo sapiens tissue_or_cell_type: Thyroid experimental_model: Same trial. limitations: Iodine treatment remained effective; nutrient roles are not interchangeable. [va-zimmermann2007-iodine] Vitamin A supplementation in iodine-deficient African children decreases thyrotropin stimulation of the thyroid and reduces the goiter rate (2007). https://pubmed.ncbi.nlm.nih.gov/17921382/ DOI: 10.1093/ajcn/86.4.1040

availability_state

nutrient_deficiency Imported condition classification; unverified.

evidence_span

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experimental_model

Controlled iron-deficient diets with pair-fed controls

exposure

Four weeks of graded iron restriction; separate food-restriction controls

limitations

Food restriction also reduced TPO; the iron effect was separately estimated. No human serum threshold or automatic iodine-treatment failure rule.

nutrient_topic

Iron research collection; topical membership is not evidence of a direct dietary effect. · Iron

organism

84 male weanling rats

plain_language

Iodine supply is only part of thyroid-hormone synthesis; its working enzyme also depends on iron-containing heme.

primary_references

[iron-p12097675] Iron deficiency anemia reduces thyroid peroxidase activity in rats. (2002). https://pubmed.ncbi.nlm.nih.gov/12097675/ DOI: 10.1093/jn/132.7.1951

tissue_or_cell_type

Thyroid and blood

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Iron: absorption, trafficking, iron-dependent enzymes and nutrient interactions (2026-09-17) · lines 901–912

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Controlled iron-deficient diets with pair-fed controls · source_derived_draft · unverified_draft

### iron-iron-tpo-deficiency Iron-deficiency anemia independently reduced thyroid peroxidase activity after accounting for food restriction in the rat experiment. Condition category: nutrient_deficiency nutrient_topic: Iron research collection; topical membership is not evidence of a direct dietary effect. plain_language: Iodine supply is only part of thyroid-hormone synthesis; its working enzyme also depends on iron-containing heme. organism: 84 male weanling rats tissue_or_cell_type: Thyroid and blood experimental_model: Controlled iron-deficient diets with pair-fed controls limitations: Food restriction also reduced TPO; the iron effect was separately estimated. No human serum threshold or automatic iodine-treatment failure rule. exposure: Four weeks of graded iron restriction; separate food-restriction controls evidence_span: {"source_cache": "artifacts/iron-research/12097675.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "26b7a5ddb0985abdb2325c7ecd505c46f02604bd4d35f68ed0c9ad67113a148e", "start_char": 0, "end_char": 1527, "text_sha256": "26b7a5ddb0985abdb2325c7ecd505c46f02604bd4d35f68ed0c9ad67113a148e"} [iron-p12097675] Iron deficiency anemia reduces thyroid peroxidase activity in rats. (2002). https://pubmed.ncbi.nlm.nih.gov/12097675/ DOI: 10.1093/jn/132.7.1951