# Impact of Calcium–Magnesium Ratio in Purified Water Remineralization on Calcium Oxalate Crystal Formation and Renal Injury

## TL;DR

This study shows that adding calcium and magnesium to purified water in specific ratios can help prevent kidney stones and kidney damage in rats.

## Contribution

The study identifies optimal calcium-to-magnesium ratios for remineralizing purified water to prevent calcium oxalate crystal formation and renal injury.

## Key findings

- Ratios of 0.5 and 3.4 Ca:Mg reduced urinary calcium oxalate crystallization and improved kidney function.
- Higher Ca:Mg ratios (over 10) showed no protective effects against kidney stones or injury.
- Pathological examination confirmed reduced renal injury with optimal Ca:Mg ratios.

## Abstract

Despite the known association between calcium and magnesium in drinking water and stone risk, the difference in stone prevention of purified water remineralized with varying calcium-to-magnesium ratios (Ca:Mg) remains unclear. Objectives: This study investigates the impact of different Ca:Mg in the remineralization of purified water on calcium oxalate crystallization and renal injury. Methods: Sixty male Sprague-Dawley rats were induced calcium oxalate crystals by a sodium oxalate diet and divided into six groups, where they drank purified water with or without remineralized varying Ca:Mg (0.5, 3.4, 10, 20, 100). Serum and urine biomarkers of renal function, renal injury, mineral metabolism, bone metabolism, and urine calcium oxalate crystals were detected. Kidneys were isolated for pathological examination. Results: Findings showed that remineralization by 0.5 and 3.4 Ca:Mg significantly reduced urinary calcium oxalate crystallization, renal injury, and improved renal function, while extreme ratios (Ca:Mg over 10) showed no benefits. Conclusions: These results elucidate the pathophysiological effects of Ca:Mg in drinking water on renal health, particularly emphasizing the protective role of the 0.5 and 3.4 in inhibiting calcium oxalate crystallization and mitigating renal injury. It provides a quantifiable reference for purified water remineralization aimed at stone prevention.