The most common kidney stones are composed of calcium oxalate, according to the University of Pittsburgh Medical Center. Kidney stones cause extreme pain and infections in the urinary tract and can result in urine outflow obstruction. Certain modifiable risk factors for calcium oxalate stones include low fluid levels, calcium deficiency and ingesting too much oxalate in your food. Diet modification is essential for calcium oxalate stone prevention.
Calcium Oxalate Stones
Calcium oxalate stones are formed when the urine becomes oversaturated with oxalate while the amount of intestinal calcium is limited. When your fluid intake decreases and your intake of oxalate increases, the oxalate sediment starts to build up in your kidneys, predisposing you to stone formation, according to "Williams Textbook of Endocrinology."
Calcium Oxalate Diet
The calcium oxalate diet is centered on the principles of decreasing oxalate intake, while maintaining good calcium levels, in order to prevent kidney stone formation. "Williams Textbook of Endocrinology" recommends that you decrease dietary protein, sodium and oxalate, while increasing your consumption of citrus fruit. On the other hand, calcium should not be restricted, because it can lead to less binding of oxalate in the intestines, which promotes the absorption of oxalate into the blood and thus results in more stone formation.
Oxalate Content in Beverages
According to "Sleisenger and Fordtran's Gastrointestinal and Liver Disease: Pathophysiology, Diagnosis and Management," the beverages that you should avoid include draft beer, cocoa, berry juices, teas, tomato juice and lemonade or limeade. These drinks contain greater than 10 mg of oxalate per serving. Beverages that can be consumed in moderate amounts are Nescafe powder, cranberry juice and grape juice. These should be limited to less than one cup per day. Drinks with the lowest oxalate include milk, coffee, apple juice, distilled alcohol, orange juice, tap water, wine and colas.
Oxalate Content in Foods
"Sleisenger and Fordtran's Gastrointestinal and Liver Disease: Pathophysiology, Diagnosis & Management" notes that meats contain little if any oxalate. Sardines contain between 2 to 10 mg per serving of oxalate and should be eaten in moderation. The vegetables to avoid include beans, carrots, beets, celery, chives, kale, leeks, sweet potatoes, and Swiss chard. You can eat moderate amounts of broccoli, turnips, eggplant, lima beans, tomatoes, peas, lettuce, cauliflower and cucumber. Feel free to eat as much as you want of sweet corn, onions, potatoes, radishes, cabbage, Brussels sprouts, avocado, mushrooms and asparagus. Fruits to avoid include berries, tangerines, concord grapes and red currants. The fruits that are the lowest in oxalate are bananas, plums, pineapple, cherries, grapefruit, white grapes, melons, pears, nectarines and mangoes.
Minerals
"Williams Textbook of Endocrinology" notes that you should limit your sodium intake to less than 3,000 mg per day in order to prevent kidney stones. Citrate, on the other hand, is something that you should increase in your diet. Citrate binds to calcium oxalate thus reducing stone formation. While you should limit your sodium and increase your citrate, calcium is a mineral that needs to be maintained in moderate amounts -- between 1,000 and 1,300 mg per day.
References
- "Low Oxalate Diet: Patient Information"; University of Pittsburgh Medical Center; 2006
- "Sleisenger and Fordtran's Gastrointestinal and Liver Disease: Pathophysiology, Diagnosis, & Management" 9th ed.; Mark Feldman, M.D., et al.; 2010
- "Williams Textbook of Endocrinology" 11th ed.; Henry Kronenberg, M.D., et al.; 2008
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