The estimation of relative nutrient intake and nutritional status by biochemical methods

T lIE development of biochemical methods for assessment of nutritional status in-volves two steps. The first is to find out what you want to measure, and the second is to develop an adequate analytical procedure. With regard to the first point, most of the current methods are not ideal since they meas-une the amount of the nutrient in serum on urine. What we are actually interested in is whether or not the essential functions ne-quining the nutrient are adequately fulfilled. Of course, this does not mean that the current methods are not useful since there is un-doubtedly a correlation between concentration and function. However, the usefulness of such methods depends in large part in es-tablishing such a relationship and determining the range over which changes in concentration can be interpreted in terms of function on health. Numerous adaptive processes, amid individual variations in function and ability to adapt, make it unlikely that the dose-response curve is a constant one in different persons on perhaps even in the same person at different times. A great deal more infonma-tion is needed about the extent and cause of differences in requirements. In survey data, most people have had to conclude that the results of biochemical tests have rarely helpe