Aluminum negatively impacts calcium utilization and bone in calcium-deficient rats

Abstract

Three studies were designed to investigate the mechanism of aluminum on calcium metabolism. An acute dose of dietary aluminum did not affect calcium absorption in rats. In the second study, rats were fed a calcium-adequate or calcium-deficient diet with 0%, 0.05%, or 0.1% aluminum. Half of the rats were sacrificed after 3 weeks and the remainder fed calcium-adequate diets with the previous aluminum concentration for another 3 weeks. Total bone calcium and breaking-strength decreased with calcium deficiency and aluminum supplementation. Femur 45Ca and PTH increased in calcium deficiency but were unaffected by aluminum. Aluminum at both levels decreased intestinal CaBP-D9K in the nonfasted rats with no effect on intestinal CaBP-D9KmRNA or kidney CaBP-D28. Aluminum did not decrease brain CaBP-D28K. In a third study of pair feeding, aluminum (0.20%) in severe calcium deficiency (0.02%) had an adverse effect on bone calcium. In summary, adverse effects of aluminum on bone health were minor unless rats were calcium deficient. © 2004 Elsevier Inc. All rights reserved.