Lead Reported in Calcium Supplements
Some over-the-counter calcium supplements contain small but measurable levels of lead, which over a period of years may have adverse health effects, researchers in Florida said in a study released today.
Researchers at the University of Florida in Gainesville analyzed 21 formulations of nonprescription calcium carbonate, which included 14 “refined” calcium products--described by scientists as those that have undergone a process to eliminate impurities--as well as seven “natural” preparations made from oyster shells.
No lead was found in a second type of supplement known as calcium acetate.
Results of the study, reported in the Journal of the American Medical Assn., showed that four of the 14 refined products and four of the seven formulations made of oyster shells contained detectable levels of lead.
The products contained only trace levels of toxic metal, less than one microgram. High levels have been associated with learning and memory disorders and have been shown to replace iron in red blood cells and deprive the body of oxygen.
The amount of lead found was 1 microgram per 800 milligram dose of calcium and between 1 and 2 micrograms per 1,500 milligrams. The prescribed dose to treat osteoporosis ranges from 1,200 to 1,500 milligrams per day.
“We don’t want people to give up on the proven benefits of taking calcium supplements,” said Dr. Edward Ross, who led the study. “The levels of lead we’re talking about here are very small and would only potentially be a problem after many years. But we also believe the less lead anyone is exposed to the better, especially since there are many calcium products on the market without detectable quantities.”
Ian Tebbett, director of analytic toxicology at Florida and a member of the research team, said lead is not added in the manufacturing process.
“It’s naturally occurring,” he said. “Calcium carbonate comes from out of the ground, and there is lead present in the earth when the calcium is mined. The good news is that the majority of the products we tested were lead-free.” Among the products studied, 15 were lead-free. Lead has been found in calcium products in the past, Ross said, and had been the subject of a lawsuit in California.
Calcium is so pervasive in the environment that its presence in soil explains why cow’s milk is such a rich source. It is present in drinking water and in a wide array of fruits and vegetables. It is mined, Tebbett said, from various sources.
An acceptable level of lead for an adult, Ross said, is about six micrograms per day. This amount is consumed daily through such activities as breathing, eating and drinking.
The resulting laboratory analysis showed the following products contained traces of lead:
Calci-Mix, manufactured by R & D Laboratories; Liqui-Cal Calcium, 600 mg, manufactured by Advanced Nutritional Technology; Calcium, 600 mg, Eckerd Corp.; Caltrate 600, manufactured by Caltrate; Hi-Calcium, from oyster shell, Eckerd Corp.; Oscal 500, Oscal; Oyster Shell Calcium, 500 with vitamin D, made by Nature Made; and Natural Oyster Shell Calcium, 500 mg with vitamin D, manufactured by Spring Valley Corp.
