Growth in the first two years of life

Compared to other periods of life, infancy is a period of rapid growth, but the relative relationships among rates of linear growth, weight accretion and brain growth vary greatly during the first years of life. Additionally, while the energy requirements for body tissue deposition as a fraction of daily energy needs decrease dramatically during infancy, brain energy demands, measured as the cerebral rate of glucose utilization, increase markedly during the same period. There is now substantial evidence that postnatal growth in infancy is associated with various consequences detrimental to health in adult life, particularly hypertension, cardiovascular disease, obesity and type 2 diabetes, but the relationships vary depending on whether one takes growth to mean statural growth or ponderal growth, as well as on the specific period of infant growth. Recently, several mechanisms have surfaced that might account for the relationships observed. These include epigenetic effects on gene expression, alterations in neuronal signaling because of inappropriate dendritic pruning, and gut microbiota effects on fat storage.