Oxalate content of selected breads and crackers

About 75% of all kidney stones are composed primarily of calcium oxalate, and hyperoxaluria is a primary risk factor for this disorder. Both absorbed dietary oxalate and endogenous oxalate syntheses contribute to urinary oxalate excretion. Since breads and crackers are widely consumed and contain a number of oxalate-containing ingredients, these products may make a significant contribution to daily oxalate intakes. Twenty-six bread samples and 19 cracker samples were analyzed for total and soluble oxalate using an enzymatic assay. Total oxalate contents of bread samples ranged from 16.5 to 45.9 mg/100 g, except for one sesame seed-containing sample that had 111.5 mg/100 g. Total oxalate for the cracker samples varied from 23.7 to 384 mg/100 g, and was dependent on both the primary ingredient as well as the secondary oxalate-containing ingredients. It appeared that samples that contained a proportionally significant quantity of sesame seeds had the highest total oxalate contents. The overall data suggested that breads are generally low to moderate in total oxalate while there is very high variability in the oxalate content of different types of crackers.