Kidney stones are hard masses that are formed from crystals in the urine. Because urine crystals form from waste products that are eliminated from the body, diet can contribute to the formation of kidney stones. In people who are prone to developing stones, a special diet may be necessary to reduce the amount of crystals in the urine and prevent the formation of hard masses.
Fluids
According to the National Kidney and Urologic Diseases Information Clearinghouse (NKUDIC), people with kidney stones should drink enough fluid each day to produce 2 quarts of urine. If a person is prone to kidney stones made of cystine, up to a gallon of water each day may be necessary to dilute the cystine that is in the urine. Drinking enough fluids can help to flush out existing stones and prevent new stones from forming.
Calcium
Calcium oxalate stones are the most common form of kidney stones. However, calcium intake does not need to be restricted to prevent kidney stones. According to the National Kidney and Urologic Diseases Information Clearinghouse, calcium that is ingested in foods and beverages binds with oxalate in the digestive tract and prevents it from entering the bloodstream. This reduces the amount of oxalate that is excreted in the urine. Additionally, the National Kidney Foundation cites a diet low in calcium as one of the factors in the development of osteoporosis and loss of bone mass.
Sodium
High sodium intake can contribute to the formation of kidney stones because the excretion of sodium from the kidneys increases the amount of calcium excreted in the urine. Information from the National Kidney and Urologic Diseases Information Clearinghouse indicates that the calcium excreted in the urine can bind with oxalate or phosphorus and result in kidney stones. Sodium intake can be reduced by avoiding fast food, luncheon meat, canned vegetables, frozen dinners and canned soups. Herbs and seasonings that do not contain sodium can be used to flavor food without increasing sodium intake.
Oxalate
Foods high in oxalate can contribute to the formation of calcium oxalate stones because the oxalate is excreted in the urine. Avoiding foods high in oxalate can help to prevent the formation of these stones. The National Kidney Foundation lists chocolate, tea, rhubarb, beans, beets, blackberries, strawberries, oranges, tofu, draft beer, sweet potatoes, peanuts, instant coffee, Concord grapes and raspberries as foods high in oxalate. Avoid these foods to reduce the amount of oxalate that is excreted in the urine.
Animal Proteins
Some kidney stones are made of uric acid, which is excreted in the urine. Animal proteins contain purines, which are broken down into uric acid, so preventing kidney stones may require limited consumption of animal proteins. Limit consumption of meats, eggs, and fish to avoid ingesting animal proteins that can increase the amount of uric acid in the urine. The National Kidney and Urologic Diseases Information Clearinghouse recommends limiting meat consumption to no more than 6 oz. each day.
