RESUMEN
<p><b>INTRODUCTION</b>Iron deficiency, associated with a decline in cognitive function, is the most common nutritional deficiency globally. The present study aimed to identify the impact of weekly iron supplements on the attention function of female students from a high school in North Khorasan Province, Iran.</p><p><b>METHODS</b>This was a blind, controlled, clinical trial study, involving 200 female students who were chosen using the stratified randomised sampling method. First, laboratory studies were performed to detect iron consumption limitations. Next, the 200 students were divided randomly and equally into case and control groups. The case group was treated with 50 mg of ferrous sulfate twice a week for 16 weeks. We compared both groups' data on attention, iron status and erythrocyte indices. Questionnaires were used to collect demographic data, while clinical data was collected using complete blood count and Toulouse-Piéron tests. Data was analysed using descriptive statistics, as well as paired and independent t-tests.</p><p><b>RESULTS</b>The mean attention scores of the case and control groups were 104.8 ± 7.0 and 52.7 ± 9.6, respectively (p < 0.001). The mean haemoglobin levels of the two groups were 12.5 ± 0.9 and 11.2 ± 1.0, respectively (p < 0.001). Compared to the control group, the attention scores and haemoglobin concentrations of the case group were found to be improved by approximately 90% and 10%, respectively.</p><p><b>CONCLUSION</b>Oral iron supplements (50 mg twice a week for 16 weeks) were able to improve the attention span and haematologic indices of female high school students.</p>