Analysis of nutrient-response relationships.

A general mathematical model is proposed to relate biological response to nutrient intake. The mathematical expression is r = sigma k0 alpha ini/sigma l0 beta ini, k less than or equal to l, alpha 0 less than greater than or equal to 0, alpha 1 ... alpha k greater than or equal to 0, beta zero ... beta l greater than or equal to 0. The model provides for saturation behavior with respect to nutrient intake, but it also provides for a wide range of shapes to the nutrient-response curve. The characteristics of the nutrient-response curve, as well as the characteristics of transformations of the primary equation, are discussed in detail. Graphical methods are discussed for obtaining quantitative estimates of parameters that describe the nutrient-response relationship. The model is compared with other models used currently in nutrient-response analysis. The steps involved in the graphical procedure are summarized.