[Enteral resorption kinetics in the aging process]

With growing age functional and morphological changes in the alimentary tract appear. The age dependence of the intestinal absorption was investigated with the help of the modified D-xylose absorption test. By means of a graphic-mathematical evaluation of the blood level kinetics of D-xylose after oral and intravenous application the absorption rapidity (constant k12), the temporary position of the relative maximum of the D-xylose concentrations in the blood serum after oral application (time tm) and the size of the relative absorption of the small intestine were established depending on the time RR (t). Within the age range of 3 to 96 years it has been proven that a slowing down of the enteral absorption occurred with growing age. By prolonging the period during which the food components are absorbed in the small intestine (shift of tm towards later times) the old organism is just as capable of complete absorption as is the young one, even though the absorption processes take place at a slower rate. Absorption disorders in old age are due to morbidity and not, sui generis, to involution.