Lead from calcium supplements contributes minimally to blood lead concentrations

We undertook a study using lead isotopes to determine the contribution of lead to blood from consumption of calcium supplements approximating the recommended daily intakes over a 6 month period. Subjects were subdivided into three groups. One treatment group ($\rm n=8$) was administered a complex calcium supplement (carbonite/phosphate/citrate) and the other treatment group ($\rm n=7$), calcium carbonate. The control group ($\rm n=6$) received no supplementation. The lead isotopic compositions of the supplements were completely different from those of the blood of the subjects. Lead isotopic compositions for the complex supplement showed minimal change during treatment compared with pre-treatment. Lead isotopic compositions in blood for the calcium carbonate supplement showed increases of up to 0.5% in the $^{206}$Pb/$^{204}$Pb ratio, and for all isotope ratios there was a statistically significant difference between bascline and treatment ($p <0.005$). Blood tead concentrations showed minimal changes.

Bone turnover in elderly females and males using bisphosphonate treatment-A pilot study


We undertook a 2 year pilot study in premenopausal and postmenopausal females and male partners in which the subjects were administered a bisphosphonate, alendronate, for 6 months. The aim ot the study was to determine how lead isotopes and lead concentrations changed in relation to bone remodelling processes. Each subject had blood and urine samples collected for markers of bone turnover and for lead isotope studies monthly for $7-9$ months before and then 3 monthly during and for up to 6 months after treatment with alendronate as an agent for inhibiting bone resorption. There were significant decreases in the lead isotope ratio, $^{206}$Pb/$^{204}$Pb, for the migrant subjects cluring treatment compared with thepre-treatment period ($\rm p<0.01$). The average bloodlead concentrations in migrant subjects decreased by about 20% during the treatment compared with the pre-treatment period ($\rm p<0.01$). The changes in lead isotopic composition and lead concentration are consistent with a decrease m bone résorption and associated mobilisation of lead during alendronate therapy