ABSTRACT
Vitamin C is a required nutrient for humans. Most animals are capable of synthesizing ascorbic acid with the exception of humans, nonhuman primates, Indian fruit bats, bulbuls, guinea pigs, and some fish. This chapter provides an overview of the data concerning the state of knowledge in these areas, and discusses how this knowledge may contribute towards achieving a recommendation for vitamin C intake. Accurate measurement of vitamin C is crucial for study of both its biochemistry and its pharmacokinetic properties. The pharmacokinetics of vitamin C are defined by its intestinal absorption, plasma concentration, cellular distribution, utilization, and excretion. The goal of in situ kinetics is to study vitamin function directly in organelles, cells, tissues, or animals, including humans. The goals of the clinical component of in situ kinetics are to determine the manner in which vitamin concentrations are achieved in humans and the effect of these concentrations on clinical parameters.
