Modelling the temporal trajectories of human milk components

This paper demonstrates how Human Milk (HM) research can be transformed from descriptive to predictive science, by applying mathematical modelling techniques to available data. The temporal trajectories of selected human milk components (HMC) were described, in the first four months postpartum, by a temporal model consisting of two phases: a short linear phase in the colostrum, triggered by the parturition; and a longer second phase, where the concentration of the component converges to a steady state. The model was fitted to data available in a recently published database of temporal HMC trajectories. Its structure proved to be suitable to describe those trajectories both at individual molecule (such as specific fatty acid, oligosaccharide, and mineral molecules) and molecule-group (such as total protein, total fat) levels. The properties of the trajectories suggest that experimental designs should follow non-linear sampling times, with shorter time intervals in the first two weeks postpartum. A selected parameter, the final stationary level, of the primary model was then studied as a function of various factors of the mother-infant-milk triad. We found that the total variation of the concentration of specific HMC is dominated by the inherent biological differences between individual mothers even in a homogeneous cohort.