Kidney stones are made from mineral crystals that accumulate in the urine. As they pass through the urinary tract, they can cause severe pain. Those at risk for kidney stones should take steps to reduce their risk for developing this severe condition. Kidney stone prevention can be accomplished with diet modification and medications for those who are at a high risk.
Fluid Intake
Increasing fluid intake can flush urine crystals out of the body and reduce the chances that a kidney stone will develop. Physicians from the Mayo Clinic recommend drinking one glass of lemonade per day, along with plenty of water. Avoid powdered mixes by making lemonade with concentrate or from scratch with fresh lemons. Lemonade can help prevent kidney stone formation because it increases the amount of citrate in the urine. The National Kidney and Urologic Diseases Information Clearinghouse indicates that citrate may prevent mineral crystals from growing into stones.
Oxalate Restriction
According to the James Buchanan Brady Urological Institute at Johns Hopkins University, most kidney stones contain oxalate and calcium. This type of stone can result from too much calcium in the urine (hypercalciuria) or too much oxalate in the urine. Your doctor may ask you to avoid high-oxalate foods if you are at risk for calcium oxalate stones. Examples of high-oxalate foods include string beans, legumes, blackberries, beats, chocolate, rhubarb, spinach, squash, strawberries, nuts, instant coffee, parsley, eggplant and draft beer.
Fiber Intake
According to Dr. Wilson Jackson and Dr. Steven Siegelbaum of Jackson-Siegelbaum Gastroenterology in Camp Hill, Pennsylvania, increasing your intake of insoluble fiber can aid in kidney stone prevention. Insoluble fiber does not dissolve in water and binds with the calcium absorbed by the intestines so that calcium is excreted in the stools. This type of fiber also speeds digestion so that less calcium is absorbed from the intestines. This results in reduced excretion of calcium in the urine. Eat foods such as wheat cereals, rye, rice, wheat bran, Brussels sprouts, carrots, cabbage, barley, beats, whole-wheat breads, cauliflower, apple skins and turnips.
Sodium Restriction
Sodium increases the amount of calcium that is excreted in the urine, which raises the risk for calcium oxalate and calcium phosphate kidney stones. Sodium can also increase the amount of urate in the urine, which can cause the formation of calcium oxalate stones. According to the University of Maryland Medical Center, people with calcium-based kidney stones should limit their sodium intake to 3,000mg per day. Avoid high-sodium foods such as canned vegetables, frozen meals, cheese, bacon, luncheon meats and canned soups.
Purine Restriction
Purines are found in the chemical structure of cells and are necessary for normal cell function. However, the breakdown of purines causes uric acid to build up, which can increase the risk for uric acid kidney stones. Some foods have high concentrations of purines and should be avoided by those who have or are at risk for developing uric acid kidney stones. Avoid high-purine foods, such as gravies, liver, anchovies, sardines, asparagus, sweetbreads, carp, calf tongue, cauliflower, chicken, crab, duck, goose, lobster, oysters, oatmeal, pork, salmon, turkey, tuna and trout.
Medications
Some medications can change the pH of the urine so that the risk of kidney stone formation is reduced. Calcium kidney stones can be prevented by taking thiazide diuretics or preparations containing phosphate. Struvite stones can be prevented with long-term use of antibiotics that prevent infection. Uric acid stones can be prevented with allopurinol, which reduces the amount of uric acid in the blood. Medication to make the urine more alkaline may be used to prevent cystine kidney stones.
