Although observational evidence suggests that concentrations of selenium , zinc , and iron are positively associated with iodine status , data from r and omized controlled trials fail to confirm this relationship .
Context The metabolism of thyroid hormones , which are essential for normal development , involves many proteins and enzymes .
It requires iodine as a key component but is also influenced by several other micronutrients , including selenium , zinc , iron , and vitamin A. Objective This systematic review was design ed to investigate the effect of micronutrient status and supplementation on  iodine status and thyroid hormone concentrations .
Treatment of iron deficiency in goitrous children improves the efficacy of iodized salt in Côte d'Ivoire.
BACKGROUND In many developing countries , children are at high risk of both goiter and iron deficiency anemia . Iron deficiency adversely affects thyroid metabolism and may reduce the efficacy of iodine prophylaxis in areas of endemic goiter . OBJECTIVE The aim of this study was to determine whether iron supplementation in goitrous , iron-deficient children would improve their response to iodized salt . DESIGN We conducted a r and omized , double-blind , placebo-controlled trial in 5 - 14-y-old children in Côte d'Ivoire . Goitrous , iron-deficient children ( n = 166 ) consuming iodized salt ( 10 - 30 mg I/kg salt at the household level ) were supplemented with either iron ( 60 mg Fe/d , 4 d/wk for 16 wk ) or placebo . At 0 , 1 , 6 , 12 , and 20 wk , we measured hemoglobin , serum ferritin , serum transferrin receptor , whole-blood zinc protoporphyrin , thyrotropin , thyroxine , urinary iodine , and thyroid gl and volume ( by ultrasonography ) . RESULTS Hemoglobin and iron status at 20 wk were significantly better after iron treatment than after placebo ( P < 0.05 ) . At 20 wk , the mean reduction in thyroid size in the iron-treated group was nearly twice that in the placebo group ( x + /- SD percentage change in thyroid volume from baseline : -22.8 + /- 10.7 % compared with -12.7 + /- 10.1 % ; P < 0.01 ) . At 20 wk , goiter prevalence was 43 % in the iron-treated group compared with 62 % in the placebo group ( P < 0.02 ) . There were no significant differences between groups in whole-blood thyrotropin or serum thyroxine at baseline or during the intervention . CONCLUSIONS Iron supplementation improves the efficacy of iodized salt in goitrous children with iron deficiency . A high prevalence of iron deficiency among children in areas of endemic goiter may reduce the effectiveness of iodine prophylaxis
Although observational evidence suggests that concentrations of selenium , zinc , and iron are positively associated with iodine status , data from r and omized controlled trials fail to confirm this relationship .
Context The metabolism of thyroid hormones , which are essential for normal development , involves many proteins and enzymes .
It requires iodine as a key component but is also influenced by several other micronutrients , including selenium , zinc , iron , and vitamin A. Objective This systematic review was design ed to investigate the effect of micronutrient status and supplementation on  iodine status and thyroid hormone concentrations .