Aluminium and strontium in calcium supplements and antacids: a concern to haemodialysis patients?

Abstract

Trace elements, most notably aluminium and strontium, have been noted for their role in the development of secondary bone disorders in haemodialysis patients. Due to the large dosages of calcium required for the maintenance of dialysis patients, this study investigated whether the source of calcium chosen for supplementation, including the form of administration (i.e. chewable forms or capsules), has an influence on the total amount of strontium and aluminium ingested daily. A convenience sample of various calcium supplement tablets and antacids was acquired, and strontium and aluminium quantification was performed by wavelength-dispersive X-ray fluorescence spectrometry. The use of readily available oyster shell-based calcium was found potentially to increase the total amount of ingested strontium substantially with concentrations reaching (2.26 ± 0.05) (mg Sr)·(g Ca)⁻¹, while the use of antacids or chewable supplements was found to contain concentrations reaching as high as (1.2 ± 0.3) (mg Al)·(g Ca)⁻¹ in the supplements analysed within this work. It is recommended that the choice of calcium supplement prescribed to individuals undergoing haemodialysis be closely regulated and noted as a possible factor in the prevalence of bone disorders reported in these patients.

Keywords:

• toxicology
• risk assessment
• method validation
• metals analysis
• inductively-coupled plasma (ICP)
• aluminium
• heavy metals
• vitamins
• toxic elements
• dietary supplements
• fish and fish products
• nutritional supplements

Acknowledgements

Funding for this project was provided by the Natural Science and Engineering Research Council of Canada (NSERC) in the form of a Discovery Grant to A. P.-M. and an Alexander Graham Bell Canadian Graduate Scholarship to E.D.S. and the Canadian Foundation for Innovation and Ontario Innovation Trust grants to A. P.-M. The authors also gratefully acknowledge the Ontario government for funding through an Ontario Scholarship in Science and Technology (E.D.S.) and, in conjunction with Ryerson University, funding for R.J. through the Ontario Work-Study programme. The authors also acknowledge Sylvia O’Sullivan (Department of Chemistry & Biology, Ryerson University) for technical assistance with the ICP-AES measurements.