Glycolate in the diet and its conversion to urinary oxalate in the rat

Less than 3 per cent of the [1-14C]glycolate administered, orally to fasted and nonfasted male Wistar rats was excreted in the feces in 48 hr. This finding indicates that the glycolate was readily absorbed from the digestive tract. An average of 3 per cent of the administered [1-14C]glycolate was also recovered in 48 hr as urinary [14C]oxalate from fasted and nonfasted rats. Significant amounts of glycolate were found in the vegetables, fruits, and beverages analyzed, but much lower amounts were found in meats and milk. Inasmuch as glycolate is naturally present in the diet and contributes to the formation and excretion of urinary oxalate, restricting the intake of glycolate may be beneficial in treating oxalate stone-forming patients.