Every year nearly 650,000 Americans visit the emergency room for kidney stone problems, reports the Urology Center of the Rockies in a 2009 article. In addition, Americans make more than three million health care visits annually regarding kidney stones, according to a 2007 report by the National Kidney & Urologic Diseases Information Clearing House. Though small stones may pass through the urinary tract undetected, large stones cause excruciating pain. Kidneys regulate phosphorus levels in the body and certain types of stones are made of phosphates derived from phosphorus, so phosphorus levels affect kidney health and vice versa.
Phosphorus
Phosphorus is important in the metabolism of protein, calcium and glucose, and it is involved with the growth, repair and maintenance of cells, production of DNA and RNA and maintenance of the acidity of blood. It plays a critical role in the storage and use of energy. Second only to calcium in abundance within your body, phosphorus works with calcium to form bones and teeth. Within the kidneys, phosphorus helps filter out waste products from the blood.
Phosphorus Balance
When balanced properly with calcium, phosphorus maintains healthy bone density and prevents osteoporosis, which is a disease characterized by thinning of bone tissues and loss of bone density. You obtain phosphorus from the foods you eat. Deficiencies lead to symptoms that can include fatigue, bone pain, stiff joints, fragile bones, irritability, weakness, loss of appetite, anxiety and poor bone growth and development, according to the University of Maryland Medical Center. Excess phosphorus--caused by kidney diseases or by consuming too little calcium or too much phosphorus--occurs more commonly. According to Spine-Health, when you have too much phosphoric acid, found in phosphorus, relative to calcium, the phosphoric acid replaces the calcium in the bone. Excess phosphorus causes osteoporosis and brittle bones.
Kidney Function and Dysfunction
Your kidneys function as a filtration system for your blood, producing urine by removing extra water and waste. Your kidneys also produce hormones that create blood cells, modulate blood pressure and strengthen your bones. Phosphorus participates in all these processes. When your kidneys don't function properly, toxins and waste build up and you develop high blood pressure, nerve damage, osteoporosis, nutritional deficiencies and cardiovascular disease, according to the National Kidney Foundation.
Kidney Stones
Hard masses called kidney stones form from crystals in urine. The most common type of stone occurs when calcium combines with phosphate, oxalate or carbonate contained in the food you eat. Kidney stones develop because of various factors, including dehydration, inherited vulnerabilities, urinary tract infections, diseases of the small intestine and gout, according to the National Kidney & Urologic Diseases Information Clearing House. Dietary factors won't cause stones in those who aren't vulnerable, but your diet can increase your risk of recurrence of stones if you are vulnerable. If you have had calcium phosphate stones, then your doctor might recommend that you alter your diet to reduce the likelihood of recurrence.
Sodium, Calcium and Water
If you have had kidney stones composed of calcium and phosphorus, your doctor and dietitian will probably recommend that you limit your sodium intake to 2,000 to 3,000mg per day, according to the National Kidney Foundation. Excess sodium leads to increased urinary calcium, which heightens your risk for developing more calcium stones. You still need calcium in your diet, but your doctor might recommend that you avoid calcium supplements. Also, the National Kidney & Urologic Diseases Information Clearinghouse recommends that you drink 2 to 3 quarts of fluid, mostly water, throughout the day. This lowers the concentration of your urine and reduces the risk of developing more stones.
Reducing Risk of Calcium Phosphate Stones
While the more common calcium oxalate stones develop in an acidic urinary environment, calcium phosphate stones thrive in basic conditions. You create a more inhospitable urinary environment, therefore, by increasing the acidity of your urine. One way to accomplish this is to use cranberry extract, advises Dr. Ronald Hoffman. Also, avoid food high in phosphorus, such as animal protein found in beef, poultry, fish, pork and other meats. Restrict your consumption of animal protein to less than 6 oz. per day. Obtain your protein instead from dairy products, legumes and brown rice. Although whole-grain products have phosphorus, the bran in grains binds with excess calcium, preventing build-up of calcium in urine. If you are not sensitive to gluten, a diet rich in whole grains may reduce your risk of developing calcium phosphate stones.
References
- Dr. Ronald Hoffman; Kidney stones: treatment and prevention; Zina Kroner, D.O.
- National Kidney Foundation: Diet and Kidney Stones
- MedlinePlus: Kidney stones
- Spine-Health; Calcium is Needed for Strong Bones; Kelly Andrews, D.C.
- University of Maryland Medical Center: Phosphorus
- Urology Center of the Rockies: Kidney Stones
