Effect of added dietary calcium on esophageal epithelial-cell proliferation in subjects at high risk for esophageal cancer: A double-blind intervention study

A randomized double-blind intervention trial was carried determine whether oral calcium supplementation could lower the proliferation of epithelial cells of the esophagus. 41 subjects identified with precanceous lesions by histopathology were randomized to receive oral supplementation of their conventional diets with 0.6 g of calcium as calcium carbonate or placebo. Both at the entry to the study and at the end of the treatment, seven months later, the subjects were examined, with an emphasis on the frequency and distribution of proliferating epithelial cells of the esophagus. Patterns of cell proliferation was defined by dividing the esophageal epithelium into cell olumns oriented perpendicularly to the basal cell layer and by comparing the numbers and fractions of tritiated thymidine-labled epithelial cells in the various cell columns and cell compartments. Before dietary supplementation with calcium, the profile of proliferating epithelial cells in the esophageal compartments in calcium group is similar to that in the placebo group, which is comparable to that previously observed in subjects with high risk for esophageal cancer. Seven months after supplementation having been started, in calcium group, proliferation was significantly reduced and the profile of the esophageal columns approached to that previously observed in subjects at low risk for esophageal cancer, however, in the placebo group, the proliferation and profile maintain at the same level as that before supplementation. Our findings indicate that oral calcium supplementation induces a more quiescent equilibrium in epithelial-cell proliferation in the esophageal mucosa of the subjects at high-risk for esophageal cancer, similar to that observed in subjects at low risk.