Abstract
The absorption of calcium occurs chiefly from the upper part of the small intestine, the reaction of whose contents has been shown 1 normally to be acid. Irving and Ferguson 2 found the absorption of calcium to be facilitated when solutions of calcium chloride, deposited directly in the intestine of dogs, were buffered so as to maintain an acid reaction. There is a direct relationship between pH of the intestinal contents and gastric free acidity 3 and with advancing age there is a reduction in gastric acidity of both sexes. 4 Clinical experience 5 indicates that periclasia, one feature of which is alveolar bone resorption, is a condition which rarely occurs before age 20 but increases markedly in incidence after age 30. The coincidence of approximately equal age distributions of cases of physiological hypochlorhydria, periclasia and senile osteoporosis suggests that some cases of alveolar bone resorption are due to deficient calcium absorption consequent upon the secretion of an amount of hydrochloric acid by the stomach insufficient to maintain the normal acidity of the intestinal contents.
Seventy-nine individuals were subjected to gastric analyses, using 50 cc of 7% alcohol as the test meal. The method of Bloomfield and Keefer 6 was used for the gastric analyses, according to which, the entire stomach contents were aspirated and all of the contents returned to the stomach except for a 10 cc sample. This procedure was repeated each 10 minutes for one hour or until the stomach was empty. The samples were separately titrated and the results calculated so as to express the average contents of free and total acidity in terms of milliequivalents of hydrochloric acid per liter.
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