Define Age as a determinants of nutrient requirements?

Age: Requirements change with increasing age between birth and maturity. Nutrient requirements per unit body weight are higher during growth and they decrease after growth has ceased. For e.g., the energy requirement of an infant is 103 Kcal per kg body weight, while for a sedentary adult male it is only 38 Kcal per kg body weight. Similarly, the protein requirement for an infant 9- 12 months is 1.5 g per kg, while that of an adult is 1g per kg body weight. Requirements increase during pregnancy as the foetus grows. In lactation, the requirements increase in proportion to the amount of milk secreted. At ages of 40 and beyond, there is a decline in the lean body tissue and a decline in activities, both of which result in a decline in the energy requirements. However, this is not accompanied by a reduction in the nutrient requirements due to a reduced efficiency of gastrointestinal function with ageing.