Iron-deficiency anemia in young children has detrimental effects on neurological development, cognitive function, exercise tolerance, immune function, and school performance [65,66].WHO defines anemia as a condition in which Hb concentration is lower than normal and is diagnosed when the concentration of Hb falls below established cutoff values [67] (the 5th percentile of those obtained of those healthy people of same sex, age, and pregnancy condition). This evidence concerns the gene GSTM1 and anemia (phenotype).