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Until recently, it was generally believed that gastric acid secretion declined with advancing age. For example, Baron described a decrease in basal secretion and peak acid output after histamine stimulation with increasing age. This study, however, used 30 years as the age to divide a small number of young and older subjects. More recent studies from the United States and elsewhere reported that basal and stimulated gastric hydrogen ion secretions did not fall if patients with atrophic gastritis and H pylori infection were excluded. Most of these studies did not include sufficient numbers of volunteers older than 65 years of age. A more comprehensive prospective study that included 22 subjects older than 65 years of age found no significant effect of age on gastric acid secretion after adjusting for the influence of atrophic gastritis and smoking. Serum gastrin levels were similar at all age groups but became elevated in the presence of atrophic gastritis. However, pepsin output was significantly depressed in older subjects in this study. A study in rats up to 24 months of age demonstrated a reduction in basal and gastrin-stimulated acid output, and lower serum and antral gastrin concentrations in older animals. A recent study in Sprague-Dawley rats between the ages of seven and 90 weeks suggested that gastrin receptor mRNA was markedly higher in 65- and 90-week-old rats than in younger animals. The causes and consequences of these changes are unclear. Further data showing that acid secretion is maintained in old age came from a study using a noninvasive quininium resin method, which distinguishes acid secretion above and below pH 3.5. In this study, basal secretion was found to be below 3.5 in nearly 90% of 248 elderly volunteers. Subjects with consistent hyposecretion usually showed serological evidence of atrophic gastritis. In young and elderly Japanese volunteers, gastric acid secretion was studied both in the 1970s and in the 1990s, showing greater acid secretion in the young and elderly individuals over these two decades in both H pylori-positive and -negative subjects. This study suggested that elderly Japanese people had lower basal and maximal acid secretion than younger individuals. It is well recognized that defense mechanisms play a major role in limiting the initiation, progress and healing of peptic ulcers. Gastric and duodenal bicarbonate secretion is an important factor that helps to limit the amount of luminal acid that traverses the mucin layer covering the mucosa. Limited studies in rodents and in humans have suggested that bicarbonate secretion may be lower in older animals and humans than in young animals and humans. The effect of injury on such bicarbonate secretion has not been studied. The secretion of mucopolysaccharides provides an important barrier to acid-induced injury of the stomach. There have been relatively few studies of changes in mucin secretion as a function of age, nor has there been any systematic evaluation of changes in hydrogen ion transfer through the mucin layer. Furthermore, studies by Dial and Lichtenberger indicating the importance of the hydrophobic properties of the gastric mucosa in protecting gastric epithelial cells have not focused on changes that might occur during the aging process. After reading all the valuable information above, you can choose the right medications for your condition and buy them at the Canadian Health&Care Mall - the best online pharmacy offering generic medications over the internet.