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Tuesday, 19 September, 2000, 17:13 GMT 18:13 UK
Lead threat from calcium tablets
Calcium supplements may contain lead
Patients taking large quantities of calcium supplements to ward off osteoporosis could be at risk from lead contamination.

Lead is often present in very small quantities from calcium mined to put in the supplements.

And while the quantities of the toxic heavy metal are slight, they are still significant, say researchers writing in the Journal of the American Medical Association.

Indeed, a person taking well over the recommended daily dose could lift their daily consumption of lead over agreed safe limits, they calculated.

Many women, particularly those past the menopause, are at risk from the effects of thinning bones.

These can lead to highly disabling fractures as their bone density swiftly falls.

One of the easiest ways to lessen the likelihood of osteoporosis is to take calcium supplements, which are available over the counter of health food shops and pharmacists.

Many perfectly healthy people take calcium to maintain bone health.

The research team, from the University of Florida, say that long-term use of high doses of calcium is likely to significantly increase their lead intake.

In children, lead poisoning can manifest itself in learning and behavioural difficulties, while in adults, it can lead to cardiovascular and kidney disease.

Long term problem

Lead study author Dr Edward Ross said: "The levels of lead we are talking about here are very small and would only potentially be a problem after many years.

"Be 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."

He called for better labelling of calcium supplements to show which had the highest quantities of lead.

The highest amount of lead found in a supplement was three micrograms in the 1,500 micrograms recommended daily dose.

The generally agreed safe level is six micrograms, although no safe level has ever been fully proven because of the long-term nature of lead poisoning effects.

Average daily ingestion of lead has already dropped significantly over the past few decades in the US, JAMA reported, as have average levels of lead in the blood.

Dr Ross said: "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."

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24 Aug 99 | Medical notes
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