Effects of age on proximal gastric motor and sensory function

Background: Healthy aging is associated with a reduction in appetite and fo od intake, which may predispose to pathologic weight loss and malnutrition. Changes in intragastric mechanisms mediating satiation in the elderly have not been studied. The aim of this study was to evaluate the effects of agi ng on i) fasting gastric compliance and the perception of gastric distensio n, and ii) food intake and gastric accommodation to a meal. Methods: Five h ealthy older (aged 68-73 years) and five healthy young (aged 22-27 years) m en, matched for body mass index, were each studied on three occasions after an overnight fast. On one day ('barostat day'), isovolumetric and isobaric distensions of the proximal stomach were performed, and meal-induced chang es in intrabag volume were measured with an electronic barostat. On another day ('tube-only day') subjects were intubated with a nasogastric tube with out an intragastric bag before the meal. On the 3rd day (control day) subje cts were given the meal without intubation. Energy intake from the buffet m eal was quantified, and perceptions assessed using visual analogue question naires. Results: During both isobaric and isovolumetric distensions the pre ssure-volume relationship did not differ significantly between older and yo ung subjects. During gastric distensions perceptions of fullness (P < 0.01) , abdominal discomfort (P < 0.05), and bloating (P < 0.05) were less in old er than young subjects, whereas the perception of hunger (P < 0.05) was les s in the young than in older subjects. There was no difference in energy in take (P = 0.44) between young and older subjects. Food intake was less on t he barostat day (P < 0.01) and the tube-only day (P < 0.01) than on the con trol day in young subjects but was not affected by the different study cond itions in the older subjects. After the meal the maximum intrabag volume oc curred later in the older than in the young subjects (105 +/- 4 min versus 36 +/- 8 min; P < 0.05), and the intrabag volume change was greater (P = 0. 05) in the older than the young subjects later in the postprandial period. Conclusions: Healthy aging is associated with decreased perception of gastr ic distension without any change in fasting gastric compliance and with red uced gastric tone late in the postprandial period when compared with the yo ung. Control of food intake is less sensitive to external stimuli in older than in young subjects.