Lead contaminated Calcium supplements.........small risk but take note

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Lead-contaminated calcium supplements pose small but avoidable risk

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9/25/2000 Many calcium supplements contain small but detectable

levels of lead, needlessly boosting consumers' exposure to the toxic

heavy metal, according to a University of Florida (UF; Gainesville)

study published in the Journal of the American Medical Association.

For most people, there is little if any danger in taking very low

doses of calcium. But researchers say the lead in some supplements

may cause problems in the long run for those who ingest several times

the normal daily requirement of calcium. Moreover, they say the

naturally occurring contamination would be an avoidable risk if

manufacturers would begin indicating lead content on their products.

" We don't want people to give up on the proven benefits of taking

calcium supplements, " said A. Ross, lead author of the paper,

who conducted the study with toxicology experts Ian R. Tebbett and

J. Szabo from UF's College of Veterinary Medicine. " 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 that

the less lead anyone is exposed to the better, especially since there

are many calcium products on the market without detectable

quantities. So while people are taking their pills, they should try

to find a source with little or no lead, " said Ross, director of the

UF College of Medicine's End-Stage Renal Disease Program. " And we

hope the industry will respond by labeling their products and finding

better raw materials for their supplements. "

The UF research comes at a time when lead poisoning has been receding

as a major public health threat, in large part because of efforts to

limit exposure to lead-containing paints, gasoline, and food and

beverage containers. One measure of the success: Average daily

dietary ingestion of lead has dropped from more than 30 micrograms to

less than 5 between the two study periods of 1982–1984 and

1994–1996,

according to the U.S. Food and Drug Administration. Average blood

levels of lead also have dropped dramatically, but poor children in

particular remain at risk for lead poisoning.

The levels found in the tested calcium samples were up to 3

micrograms for doses up to the 1,500 milligrams of elemental calcium

recommended for women trying to prevent or treat osteoporosis. Groups

with even more significant calcium needs, such as dialysis patients,

would be exposed to even higher amounts.

It is impossible to avoid lead in the diet completely. The heavy

metal, which can lead to learning and behavioral difficulties in

children and cardiovascular and kidney disease in adults with

excessive exposure to it, occurs naturally in the air, water, soil,

and many foods. Thus, it can be present in the mineral beds that

provide calcium sources for supplements. Because lead is so

ubiquitous, the Florida research group says it is important to avoid

lead when possible.

" We probably would not have done this study 20 or 30 years ago.

People then were exposed to many times the amount of lead in these

supplements, " Ross said. " But with progress in environmental

controls, we can now ask, 'How low do you have to go to ensure

safety?' No entirely safe level of lead has ever been established. "

The UF scientists are not the first to raise the issue of lead in

calcium supplements, but they sought to quantify how much products

currently contain, especially in light of physician recommendations

in recent years to increase calcium intake.

For the study, staff at the Analytical Toxicology Core Laboratory

based at the College of Veterinary Medicine tested lead levels in

calcium supplements corresponding to doses recommended for children,

women, and patients on dialysis. They examined 21 formulations of

over-the-counter calcium carbonate, as well as one brand of

prescription-only calcium acetate. They did not test any calcium

citrate formulations.

Just two of the products listed lead on their labels, asserting that

they were " essentially lead-free. " Researchers could not detect any

lead in those samples.

Overall, eight products, all nonprescription, had detectable levels

of lead. These products included name brands, as well as both refined

and " natural " varieties derived from oyster shells.

If taken in normal daily dose ranges—800 milligrams for children

or

1,500 milligrams for women trying to prevent bone loss—the

supplements would fall below the 6 microgram total daily exposure

limit suggested by many experts. The UF team as well as other

investigators believe it's reasonable to expect the supplements to

contribute no more than 1 microgram of lead to the daily exposure

limit.

Of the products tested, a children's dose could result in a maximum

of 1.8 microgram of lead, and the women's dose 3 micrograms.

But people with failing kidneys, who often are directed to consume

many times the normal dose calcium, could find themselves taking in

as much as 20 micrograms of lead daily, according to the study. Also

at risk for higher lead ingestion are people who greatly exceed

recommended calcium doses in the mistaken belief that the more they

take, the better off they will be.

For consumers, picking a lead-free brand is difficult without

additional help from manufacturers.

" Just because a product is a name brand produced by a nationally

recognized pharmaceutical company does not mean it has a lower lead

content than a generic brand, " said Tebbett, director of the

Analytical Toxicology Core Laboratory. " One cannot even assume that a

given brand is uniformly safe, in that some of their products may

have high lead levels, and others, low lead levels. "

" We don't want people to assume from our tables in the JAMA article

that any one brand would continue to be safe or toxic, " Ross

said. " On samples from a different lot, the results could flip-flop.

That's why we need manufacturers to voluntarily obtain better raw

material, measure the amount of lead and label their products. "