GSTM1 and anemia (phenotype): Iron deficiency until recently was thought to be the most common cause of anemia in low‐ and middle‐income countries.11 In 2015, the World Health Organization (WHO) estimated that iron deficiency anemia (IDA) accounts for roughly 50% of cases in women and 42% in children.11 As indicated, nutrition interventions alone have been unsuccessful in normalizing hemoglobin (Hb) levels.