Which calcium supplements have the highest risk of lead contamination, and is this a concern for patients?

A study by Ross et al, entitled “Lead Content of Calcium Supplements” investigated different OTC and prescription calcium supplements to determine the lead content of these products. The purpose was to determine the lead exposure from popular brands of calcium in dosages for childhood recommended daily allowances (RDA), osteoporosis, and phosphate binding in dialysis patients.

They took 23 different samples from national chains of pharmacies, discount merchandisers, and manufacturers and analyzed them. They found that a number of products and dosing regimens would potentially result in lead toxicity. Of 7 formulations labeled as being of natural or oyster shell sources, 4 had measurable lead content. In fact, when dosed in the ranges commonly used for patients with renal disease, all 4 products imparted more than 6-ug/day, which is an accepted maximal limit of lead. When taken in high doses, the daily exposure of lead from these products could easily be around 10ug/day.1 Of 14 preparations of “refined” calcium carbonate, 4 preparations had detectable lead. These levels were similar, and in some cases, greater than the levels found in oyster shell calcium. In fact, with high renal doses, lead exposure could reach 20ug/day. Two formulations of non-prescription calcium carbonate that were labeled “lead free” had immeasurable lead content (<0.25ug/g of lead per unit dose). The prescription only calcium acetate product had immeasurable lead content as well.

The need for calcium supplementation is important for many groups of people, specifically patients with osteoporosis, lactating mothers, children, and dialysis patients. Considering that this study found calcium supplements containing considerable amounts of lead are readily available and that lead toxicity is a known health problem, this should be viewed as a public health concern. This study reminds readers that the amount of lead in products identified by this study is not necessarily consistent, but does give a better idea of what to expect. This study also recommends to consumers, especially patients who need large dosages of calcium, to purchase products that claim to be essentially lead free or invest in the more expensive prescription products.

Some of the products found to have the highest lead content from this study are as follow:
Caltrate 600
Eckerd Brand-Calcium 600
Advanced Nutritional Technology- Liqui-Cal Calcium 600 Softgels

Reference:
Ross E, et al. Lead content of calcium supplements. JAMA 2000; 284(11): 1425-1429.