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 .
Correlations of Trace Element Levels in the Diet, Blood, Urine, and Feces in the Chinese Male
In order to explore the associations between trace elements in dietary intake and the other three biological media ( blood , urine , or feces ) and inter-element interactions among the latter , we simultaneously collected 72-h diet duplicates , whole blood , and 72-h urine and feces from 120 free-living healthy males in China . Correlations among the toxic ( cadmium [ Cd ] , lead [ Pb ] ) , and nutritionally essential ( zinc [ Zn ] , copper [ Cu ] , iron [ Fe ] , manganese [ Mn ] , selenium [ Se ] , iodine [ I ] ) elements were evaluated using Spearman rank correlation analysis based on analytical data determined by inductively coupled plasma-mass spectrometry . Dietary Cd intakes were highly correlated with the fecal Cd and blood Cd levels . Inverse correlations were found for Fe – Cd and Fe – Pb in both diet versus blood and diet versus feces . Cd – Zn and Cd – Se were significantly directly correlated in the urine and feces . Cd – Se and Pb – Se were negatively correlated in blood . In addition , there existed an extremely significant association between urinary Se and urinary I. Moreover , the other two highly direct correlations were found for Se – Fe and for I – Fe in urine . Improved knowledge regarding their mutual associations is considered to be of fundamental importance to underst and more the complex interrelationships in trace element metabolism
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 .