Kidney stones are hard masses made up of crystals that separate from urine in your urinary tract. The most common type contains calcium along with phosphate or oxalate, according to the National Kidney and Urologic Diseases Information Clearinghouse. Although most kidney stones are passed out through urine without need for medical treatment, they can cause bothersome symptoms, including pain that has been compared to childbirth in intensity. Dietary changes may help minimize calcium stone formation and symptoms.
Guidelines
The most important dietary steps you can take to lower your calcium stone risk, according to the University of Maryland Medical Center, include consuming more fluids and limiting sodium and protein. Eating more potassium-rich foods may also guard against calcium stone formation. Although calcium is contained in the stones, calcium-rich foods do not contribute to their development. If you're prone to calcium oxalate stones, you should aim for 800 mg of calcium from foods daily.
Foods to Limit
Protein increases levels of uric calcium and oxalate in your urine, according to the UMMC, and reduces citrate, which may help reduce stone formation. To limit protein, you can avoid particularly protein-rich foods, such as red meat, poultry, seafood and eggs, or consume them in smaller portions. Salt also increases your kidney stone risk. High-salt foods include canned vegetables and soups, processed meats and cheeses, soy sauce, frozen entrees and salty snack foods, such as pretzels and potato chips.
Foods to Emphasize
Dairy products, fortified soy milk, canned salmon and tuna, leafy greens, almonds and tofu, can help you meet your daily calcium needs. One cup of low-fat milk contains 300 mg of calcium. Low-sodium, potassium-rich foods include fresh fruits and vegetables, such as apricots, bananas, cantaloupe, carrots, peas, squash and leafy greens. Beans, peas, lentils and tofu provide valuable fiber-rich alternatives to meats and seafood, which are higher in protein and devoid of fiber. Fiber may also guard against kidney stones. Additional high-fiber foods include raspberries, oatmeal, barley, pears, broccoli and artichokes.
Fluids
The National Kidney and Urologic Diseases Information Clearinghouse recommends drinking enough fluid, particularly water, to produce two quarts of urine each day. Keep in mind that time in hot weather and intense exercise increase your fluid needs. Orange juice, lemon juice and lemonade may help prevent calcium oxalate stones, but may be harmful if you're prone to calcium phosphate stones. Avoid grapefruit juice, dark colas and cranberry juice, which may worsen your symptoms.
References
- National Kidney and Urologic Diseases Information Clearinghouse: Kidney Stones in Adults
- University of Maryland Medical Center: Kidney Stones: Prevention
- National Kidney and Urologic Diseases Information Clearinghouse: Diet for Kidney Stone Prevention
- Colorado State University Extension: Potassium and Health
