Sunday, July 25, 2010

Lead in calcium supplements - how is NZ going?

Lead in food and drink is disturbingly frequent. However the level is normally under the "safe" limits. This lead comes from historical leaded petrol, lead in solder in old water pipes..... Anyway lead is also naturally found in limestone/calcium deposits. Lead can also be bio acculuated in the shells of filter feeders such as oysters.

This is relevant because calcium supplements are often made either from limestone (calcium carbondate) or from oyster shells, which are a waste product in the seafood industry.

About 15 years ago I had of a study that had found lead in calcium supplements. Came across a paper today that was in my read/file pile. It is a 2000 paper that found:
  • Four of the seven oyster shell supplements had lead in them.This being of the approximate level of 1 µg/ supplement pill (800 µg dose). Any lead intake is unhealthy. However any level below 3 µg per 800 µg tablet.   
  • Four of the 14 limestone supplements had lead in them.With an average of 1.5 µg per 800 µg dose.    
So clearly you want to have a supplement with zero levels of lead, not just meeting the high standard. Which products on NZ shelves have lead in them? That is a very good question. I will email the suppliers and keep you posted. Please contact me if you would like your brand questioned, as there are a lot of brands in NZ and I'm not aware of all of them.

Lastly remember it is not just your calcium intake that builds strong bones. You MUST have a high vitamin D level as well. 

Reference Edward A. Ross; Nancy J. Szabo, PhD; Ian R. Tebbett, Lead Content of Calcium Supplements JAMA. 2000;284:1425-1429. :

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