Aluminum toxicity to bone: A multisystem effect?

Aluminum (Al) is the third most abundant element in the earth's crust and is omnipresent in our environment, including our food. However, with normal renal function, oral and enteral ingestion of substances contaminated with Al, such as antacids and infant formulae, do not cause problems. The intestine, skin, and respiratory tract are barriers to Al entry into the blood. However, contamination of fluids given parenterally, such as parenteral nutrition solutions, or hemodialysis, peritoneal dialysis or even oral Al-containing substances to patients with impaired renal function could result in accumulation in bone, parathyroids, liver, spleen, and kidney. The toxic effects of Al to the skeleton include fractures accompanying a painful osteomalacia, hypoparathyroidism, microcytic anemia, cholestatic hepatotoxicity, and suppression of the renal enzyme 25-hydroxyvitamin D-1 alpha hydroxylase. The sources of Al include contamination of calcium and phosphate salts, albumin and heparin. Contamination occurs either from inability to remove the naturally accumulating Al or from leeching from glass columns used in compound purification processes. Awareness of this long-standing problem should allow physicians to choose pharmaceutical products with lower quantities of Al listed on the label as long as this practice is mandated by specific national drug regulatory agencies.