Foods that are high in oxalate are soy products, wheat germ, quinoa, potato chips, French fries, nuts and nut butters. High oxalate fruits are berries, kiwis, figs and purple grapes. Vegetables to limit include rhubarb, okra, leeks, spinach, beets and Swiss chard. It is also advisable to restrict tea, cocoa and chocolate.
People on low-oxalate diets are able to take other steps to help control their oxalate levels. For example, oxalate forms when the body processes vitamin C, so individuals should not consume large doses of the vitamin. Any supplements should not exceed 500 milligrams per day.
Cutting back on salt helps, as well. Too much sodium causes excessive calcium loss through the urine.
Sufficient amounts of calcium are important. Calcium binds oxalate in the intestines, which reduces its absorption. Therefore, people should have two to three servings of high-calcium foods daily. If someone does eat a high oxalate food, it helps to partner it with a calcium-rich food. Berries and yogurt or spinach salad with cheese are good combinations.
When individuals absorb too much oxalate through their digestive tracts, excessive oxalate ends up in their urine. This increases the likelihood of forming calcium oxalate kidney stones, the most common type in the United States.