Possible Role of Carbohydrate-Induced Calciuria in Calcium Oxalate Kidney-Stone Formation

Since nutrient ingestion has been shown to augment urinary calcium excretion in normal subjects, we compared the effect of ingestion of glucose or sucrose on urinary calcium excretion in normal subjects, those who form calcium oxalate kidney stones and their relatives. Patients and relatives had significantly higher urinary calcium excretion rates in control periods than normal subjects, but considerable overlap was present. After sugar ingestion each patient and relative achieved higher rates of calcium excretion than any normal subject. In addition, the patients and relatives had a greater antidiuresis after sugar and achieved much higher urinary calcium concentrations. Coupled with higher basal rates of urinary calcium excretion, the exaggerated augmentation of calcium excretion after carbohydrate ingestion could favor calcium salt precipitation in patients who form stones and in their relatives.