Calcium Absorption and Achlorhydria

To the Editor: Dr. Recker concludes in his article on calcium absorption and achlorhydria (July 11 issue)¹ that if calcium carbonate is to be used as a prophylaxis against bone loss, it should be taken with meals. The hydrogen ion concentration of the test meal he used was approximately 1 μmol per liter (pH 5.8), and this would be enough to dissolve only microgram quantities of calcium carbonate. To test whether this pH was typical of that of a day's intake of food, I measured the pH of 15 samples of homogenized diets from calcium-balance studies; the pH ranged from.