OBJECTIVES: Micronutrient (MN) deficiencies cause a considerable burden of disease for children in many middle and low income countries, with impaired physical and cognitive development and increased morbidity. MN fortified milk or cereals are an important food component during adolescence and often used in school feeding programmes, but their specific impact on health is poorly documented.

METHODS: We performed a systematic review and meta-analysis to assess the impact of MN fortified milk and cereal food on the health of children and adolescents (aged 5-15 years) compared with non-fortified food. We reviewed randomised controlled trials (RCT) using electronic databases (MEDLINE, EMBASE, Cochrane library; latest search: January 2017), reference list screening and citation searches. Three pairs of reviewers independently assessed 1916 studies for eligibility and extracted data. We assessed the risk of bias and rated quality of evidence using the GRADE approach.

RESULTS: We included 23 RCT (often multi MN fortification) with 29 pair-wise comparisons. A modest and non-significant increase of haemoglobin values emerged (0.07 g/dl [95%-CI: -0.02 to 0.17]; 13 RCT with iron fortification; very low certainty). In one ex-post subgroup analysis, multi MN fortification had a significant effect on haemoglobin (0.13 g/dl [95%-CI: 0.03 to 0.23]; 6 RCT), when comparing fortified to non-fortified milk and cereals. No significant impact was found on anaemia risk (risk ratio 0.90 [95%-CI: 0.78 to 1.03]; 11 RCT), but on iron deficiency anaemia (risk ratio 0.38 [95%-CI: 0.18 to 0.81]; 5 RCT). Fortified milk and fortified cereals showed similar effects. Follow-up periods were often short and the impact on anthropometric measures was weak. Some moderate-quality evidence emerged for the improvement of cognitive performance, functional measures and morbidity.

CONCLUSIONS: Fortification of milk and cereal food had only marginal health effects in children and adolescents from 5-15 years, but iron deficiency rates at baseline were relatively low.