Scientists once thought that the greater the oxalate level in a food, the more likely it was to increase the risk of forming a kidney stone. However, researchers have discovered that consumption of only certain oxalate-containing foods is likely to significantly increase urinary oxalate. The foods reported by at least one group of researchers to cause a significant increase in urinary oxalate include spinach, rhubarb, beets, nuts, chocolate, wheat bran, strawberries, peanuts, almonds, and tea. Not every study has found tea to significantly increase urinary oxalate. There remains no universal consensus on which oxalate-containing foods belong on this list. Nonetheless, there is a growing awareness that the important issue for people with a history of kidney stone formation is to avoid certain high-oxalate foods--those that are most responsible for increasing urinary levels of oxalate.
To avoid oxalates ask about ingredients at restaurants and others' homes, and read food labels. The following list is not complete. Consult with a healthcare professional before making any significant changes to your diet.
These foods are high in oxalate (greater than 10 mg per serving):
These foods are moderately high in oxalate (2 to 10 mg per serving):