Lead content of calcium supplements

Context Substantial quantities of lead have been reported in some over-the- counter calcium supplement preparations, including not only bonemeal and do lomite, but also over-the-counter natural and refined calcium carbonate for mulations. Examination of this issue is warranted given recent increases in physician recommendations for calcium supplements for prevention and treat ment of osteoporosis. Objectives To determine the lead content of calcium supplements and to quan tify the lead exposure from popular brands of calcium in dosages used for c hildhood recommended daily allowance, osteoporosis, and phosphate binding i n dialysis patients. Design and Setting Analysis of lead content in 21 formulations of nonprescr iption calcium carbonate (including 7 natural [ie, oyster shell] and 14 ref ined), 1 brand of prescription-only calcium acetate, and 1 noncalcium synth etic phosphate binder conducted in March 2000, Main Outcome Measures Lead content, assayed using electrothermal atomic abs orption, expressed as micrograms of lead per 800 mg/d of elemental calcium, per 1500 mg/d of calcium, and for a range of dosages for patients with ren al failure. Six mu g/d of lead was considered the absolute dietary limit, w ith no more than 1 mu g/d being the goal for supplements. Results Four of 7 natural products had measurable lead content, amounting t o approximately 1 mu g/d for 800 mg/d of calcium, between 1 and 2 mu g/d fo r 1500 mg/d of calcium, and up to 10 mu g/d for renal dosages, Four of the 14 refined products had similar lead content, including up to 3 mu g/d of l ead in osteoporosis calcium dosages and up to 20 mu g/d in high renal dosag es, No lead was detected in the calcium acetate or polymer products. Lead w as present even in some brand name products from major pharmaceutical compa nies not of natural oyster shell derivation. Conclusions Despite increasingly stringent limits of lead exposure, many ca lcium supplement formulations contain lead and thereby may pose an easily a voidable public health concern.