Objectives: This study was undertaken to identify a South African mineral water containing relatively high concentrations of calcium and magnesium and to investigate its effect on urinary biochemical and physicochemical risk factors associated with calcium oxalate kidney stone formation.
Design: The study followed a change-over design in which each subject followed a randomised sequence of three water-drinking protocols involving their normal diet, a calcium and magnesium-rich mineral water and a mineral water deficient in these elements.
Setting: University of Cape Town.
Subjects: 54 volunteers without any previous history of stone disease (27 men, 27 women) in the age group 21-35 years and 31 with a history of calcium oxalate kidney stones (24 men, 7 women) in the age group 25-45 years participated in the study.
Outcome measures: Both mineral waters favourably altered several risk factors. However, the effect of the calcium- and magnesium-rich water was shown to be significantly greater as it altered a larger number of these factors and induced several unique changes that were not achieved by the other water.
Conclusions: The risk of calcium oxalate stone formation can be significantly reduced by consumption of mineral water which is rich in calcium and magnesium.