Studies of bladder stone disease in Thailand. XVII. Effect of exogenous source of oxalate on crystalluria

The present study examined (1) dietary sources of oxalic acid in village infants living in areas known to be endemic for bladder stone formation and (2) the effect of orthophosphate supplementation on crystalluria due to a high exogenous oxalic acid. It was found that local vegetables and forest plants commonly consumed by villagers of all ages contain oxalic acid levels as high as 967 mg/l00 g fresh weight. When these vegetables were given to village infants in the usual amounts, i.e., supplying oxalic acid at approximately 5 mg/kg body wt per day, it led to heavy oxalcrystalluria of different forms and various sizes with clumping. During the entire study, the infants continued to receive breast milk, premasticated glutinous rice, and water. The administration of orthophosphate orally practically eliminated crystalluria and crystal clumping. From this study, it is suggested that exogenous as well as endogenous sources of oxalic acid must be considered in all future studies on the etiology of bladder stone disease.