Tritium transfer from diet to human

Abstract

The direct transfer of organically-bound³H (OBT) of diet to that in the human body is reasonable, since the human body needs essential amino acids and fatty acids. Metabolic models of³H which were recently developed for the human body took this direct incorporation into account. Data for fallout³H in diet and human tissues were used to validate model parameters, although such data are relatively scarce. However, a simple equilibrium between dietary³H and human body³H was assumed for such validations. The simple equilibrium assumption means completely neglecting past³H concentration in the human body. When the model consists of compartments which have long mean residence times, estimated³H concentrations in the human body from the simple equilibrium assumption can differ significantly from results of adequate calculation considering contribution of past human³H concentrations. The examples of such calculations are described in this paper. Results of the calculations show that suitable environmental³H transfer models are necessary to use fallout³H data for the validation of³H metabolism models.