In the study below, chickenfeed was supplemented with selenium or selenium and iodine.
Selenium increased 61% in the egg yolks of the chicken fed selenium plus iodine, suggesting that the Iodine addition may help with selenium absorption.
As a bonus, there was a signficant decrease in Cd in the egg yolk, implying a high sensitivity to Cd to the detoxifying effects of the combination of selenium and iodine.
J Trace Elem Med Biol. 2008;22(3):234-41. Epub 2008 Jun 5. Links
Selenium interactions with essential and toxic elements in egg yolk from commercial and fortified eggs.
Bargellini A, Marchesi I, Rizzi L, Cauteruccio L, Masironi R, Simioli M, Borella P.
Department of Public Health Sciences, University of Modena and Reggio Emilia, Modena, Italy.
The main objective of this work was to evaluate the interaction between selenium concentration in both commercial and Se-enriched eggs and other essential/toxic elements (Ca, Mg, Fe, Zn, Pb, and Cd), taking into account a possible synergic action of iodine. Commercial eggs were purchased from several sale points or directly from the producers (farmyard eggs). Fortified eggs were obtained by supplementing chickenfeed for 6 weeks with Se as sodium selenite (1.0mug/g Se) or Se plus Iodine (1.0mug/g Se+3.7mug/g I). Se in experimental egg yolks significantly increased over the basic value by 39% in the Se group and 61% in the Se+I group, suggesting that I addition may enhance Se absorption. Levels of Se in commercial yolks were identical in free-range, barn or battery eggs, but significantly lower in farmyard and higher in organic eggs where the Se content approximated that found in Se fortified eggs. A significant reduction in Cd was observed in Se+I treated yolks compared to both control and Se alone diet, thus suggesting a high sensitivity of Cd to the detoxifying effect of Se combined with I. Furthermore, Se+I supplementation was associated with a significant Zn reduction, a finding which needs clarification to avoid attempts to maximize one component affecting the levels of other essential elements.