Effectiveness of the nutritional supplement used in the Mexican Oportunidades programme on growth, anaemia, morbidity and cognitive development in children aged 12-24 months.

Objective: To determine the effectiveness of the nutritional supplement developed for the Oportunidades programme on growth, prevalence of anaemia, morbidity and cognitive function of pre-school children.

Design: In a randomised, placebo-controlled longitudinal trial, children were assigned to one of three experimental treatment groups: Oportunidades food supplement (OFS), powdered milk (PM) and placebo (PL). Treatments were administered daily for 6 months. Weight, height and Hb were measured in all participants before and after supplementation. Morbidity was assessed two times per week for 6 months using validated questionnaires. The Bayley Scale of Infant Development Test was administered at baseline and after 6 months.

Setting: Three marginal rural communities of the state of Queretaro, Mexico.

Subjects: A total of 224 children, mean age 22·4 (SD 5·9) months, were recruited. After the 6-month intervention, 186 completed the study.

Results: No differences were found in the adjusted changes of weight, height or anaemia between treatment groups and PL. No differences were found in the number of episodes of gastrointestinal or respiratory disease, nor were there any differences in cognitive performance between treatment and PL groups after 6 months of supplementation.

Conclusions: Daily supplementation of 12-24-month-old children with OFS has no additional benefits in growth, anaemia, morbidity or cognitive performance.