Define Methods for Studying the Nutrient Requirements?

1) Population survey of nutrient intakes of healthy individuals is one method of estimating nutrient requirements. The average intake by healthy individuals in a particular life stage and gender group represents the requirement for that group, currently this method is used only when there is not adequate data on requirement distribution in population groups.

2) For infants and children, growth and body weight gain has been used along with the nutrient composition of body tissues to arrive at the nutrient requirements.

3) Experimental methods such as depletion and repletion of nutrients and nutrient turnover studies have helped in determining the minimum requirements and recommended allowances.

4) Some methods like the obligatory losses which were used at one time for estimating the maintenance requirements of nutrients are no longer in use as they represent a not physiological state.