Influence of nutritional composition on the circadian rhythms of patterns of urinary pH and its role in kidney stone prevention

This study assessed the impact of nutritional composition on circadian rhythms of urinary pH to analyze dietary influence on urine acidity, which could support the medical management of urolithiasis. A healthy 21-year-old male followed four different diets (usual, acidic, alkaline, and DASH) over four weeks, recording micturition, nutritional, and anthropometric data. Urinary pH was measured multiple times daily, yielding average values of 6.02, 5.66, 6.06, and 5.93 per week, respectively, while Net Acid Excretion (mEq/day) presented values of 65.54, 134.93, 29.60, and 16.27 in the same order. A significant correlation (r = 0.49, P < 0.01) was found between water intake and urinary pH. The findings confirm that diet influences urinary pH and highlight the value of circadian analysis, which provides more detailed information on daily variability compared to a single 24-hour measurement.