Complementary Feeding, Micronutrients and Developmental Outcomes of Children.

The period of complementary feeding (6-24 months of age) can be a challenging and vulnerable time for infant nutrition due to disproportionately high requirements for metabolic processes, rapid developmental processes, and limited gastric capacity. This is a period of crucial brain development where high caloric intake is necessary to allow synaptogenesis (creation of channels between neurons for communication), and maintenance of established synapses, myelination (laying the myelin sheath around neuronal axons) and everyday psychological functioning. Key nutrients needed for infant brain development include iron (required for oxygen provision to metabolize energy), fatty acids (for cellular membranes and myelin) and protein (for structural support, such as in myelin). Deficiencies in key nutrients during the complementary feeding period have been consistently linked to child development outcomes. Observational studies have consistently demonstrated links between nutrient deficiencies and impairments in intellectual abilities, work capacity, behavioral functioning and even delayed mental and motor development. Yet results from a number of interventions using food, individual nutrients or multiple micronutrients with child development assessments are mixed, possibly partly due to differences in interventions (nutrients and timing), populations, baseline nutrient status, sample sizes, attrition and method of assessment.