Calcium treatment of enteric hyperoxaluria after jejunoileal bypass for morbid obesity

The effect of oral calcium on oxalate absorption was studied in eight patients with secondary hyperoxaluria after jejunoileal bypass for morbid obesity during a standardized diet with a fixed supply of fat, calcium, and oxalate. A supplementary calcium dose of 2000 mg/day reduced renal oxalate excretion from 119 to 60 mg/24 h (median values, p < 0.01). Correspondingly, 14C-oxalate absorption decreased from 28% to 9% (p < 0.01). No statistically significant increase in urinary calcium was observed. The study shows that renal oxalate excretion in patients with enteric hyperoxaluria can be reduced by oral calcium. However, we doubt that it has any practical, clinical importance.