RESUMEN
BACKGROUND: School feeding programs are important interventions for improving the nutritional status of students. Therefore, this study was conducted to evaluate the effects of milk supplementation on physical, mental and school performance of students. METHODS: This case-control population-based intervention was conducted on 469 students from 4 schools in a medium socio-economic status region in Tehran. The schools were chosen by Iranian ministry of education and training and they were allocated in case and control groups randomly. All the students in the first to third classes in the intervention schools were daily consumed sterilized and homogenized milk for three months (250 ml each). Anthropometric measurements were done according to the standard methods. For evaluating the mental function, the Raven's Coloured Progressive Matrices (CPM) and Wechsler Intelligence Scale for children (verbal, non-verbal, total Intelligent Quotient) were conducted on students. School performance was assessed by grade-point averages of each student. RESULTS: The weight of children was significantly different between control and intervention group at the end of the study among girls (23.0 ± 3.8 vs. 23.8 ± 4.3 kg; p < 0.05). Psychological tests' scores were significantly different between the control and the intervention groups (p < 0.05) at the end of the trial among boys. The grade-point average was significantly different at the end of the trial between the intervention and the control group among girls (p < 0.05). CONCLUSIONS: School feeding programs focus on milk supplementation had beneficial effects on the physical function and school performances specifically among girls in Iran.