Specific cognitive effects of mild iron deficiency and associations with blood polymorphisms in young adults

This study of 172 university undergraduates examines the relationship of five cognitive tests to iron levels (as measured by a haematofluorometer) and three polymorphic blood markers implicated in either iron metabolism or transport. The markers used were the red cell antigens of the ABO system and the serum proteins transferrin (TF) and haptoglobin (HP). Negative correlations were found between zinc protoporphyrin (ZPP) level and three spatial tests, Reflected Figures (r = -0.23), Form Recognition (r = -0.20) and Block Design (r = -0.18). These findings suggest a possible effect of mild iron decrement upon spatial performance involving spatial visualization and item identification and manipulation. A significant association (P less than 0.05) was also recorded between ZPP level and TF subtype; the rarer the TF subtype, the higher the ZPP level. No support was found for a previously reported association between Block Design performance and HP.