The limited capacity of the infant’s immature renal system during the first few months of life justifies delaying the introduction of solid food. The immature renal system has only a limited ability to filter out waste products or to excrete sodium. As the kidney mature, they can handle higher solute loads. Until then, foods with a high renal solute load incur too great an obligatory waste loss and cause dehydration, a life-threatening condition. To protect against dehydration and to compensate for the higher renal solute load, water should be offered to the infant regularly once solid food is added to the diet.
Adequate nutrition during infancy plays a crucial role in normal growth and development. The rapid growth and metabolism of infant demand an ample supply of all the nutrients.