Sodium Chloride–Dependent Oxalate Absorption in the Human Gut

We investigated the effect of sodium chloride intake on oxalate and calcium metabolism in the human body. In healthy subjects with a simultaneous intake of sodium oxalate (4 μmoles/kg body weight) and sodium chloride (1.2 mmoles/kg body weight), the change in oxalate-creatinine ratio was 2.04 ± 0.74, and 3.25 ± 1.29 (means ± SD), respectively, after 2 and 4 hours of oxalate intake (n = 8). The magnitude of the change in the ratio was significantly greater in the case with simultaneous intake of sodium chloride and sodium oxalate in comparison to the case with an intake of sodium oxalate alone (P < 0.05 and P < 0.01 after 2 and 4 hours of intake of oxalate, respectively). In subjects with an intake of sodium chloride alone, the change in calcium-creatinine ratio was 49.07 ± 29.96 and 0.363 ± 0.309 (means ± SD), respectively, after 2 and 4 hours of sodium chloride intake (n = 3). The results suggest that high sodium intake can be one of the risk factors for urolithiasis.