The effect of nutritional supplementation on physical activity and exploratory behavior of Mexican infants aged 8-12 months.
Physical activity and exploration in infancy affect physical and cognitive development. Nutritional supplementation improves activity in severely malnourished infants, but the evidence in mild-to-moderately malnourished and nutritionally at-risk infants is equivocal. We tested the effect of multiple-micronutrient supplementation on physical activity and exploration in Mexican infants. Using a quasi experimental design, we analyzed data from a supplementation study that lacked a placebo-control group. We compared infants between 8 and 12 months measured at baseline who had received no supplementation (comparison group, n=78), with infants 8-12 months measured after 4 months of daily supplementation (treatment group, n=109). The treatment consisted of three supplement types: micronutrient powder, syrup (each containing only micronutrients) and a milk-based, fortified-food supplement (FFS; containing micronutrients and macronutrients). We formed the micronutrient-only group (MM) by combining the micronutrient powder and syrup groups. We measured activity and exploration by direct observation and used cluster analysis to form and characterize activity and exploration clusters. We performed logistic regression with activity or exploration cluster as the outcome variable and treatment versus comparison and MM or FFS versus comparison as the predictor variables. Treatment versus comparison increased the odds of being in the high activity (odds ratio (OR)=2.35, P<0.05) and high exploration (OR=1.87, P<0.05) cluster. MM increased the odds of being in the high activity (OR=2.64, P<0.05) cluster and FFS increased the odds (OR=3.16, P<0.05) of being in the high exploration cluster. Nutritional supplementation benefited activity and exploration in this sample of Mexican infants.