Kidney stones form when high concentrations of certain substances are present in your urine. Uric acid is one of these substances; it is affected by purines in your diet and leads to the formation of uric acid stones. Limiting purine-rich foods in your diet can help reduce the risk of stone formation and other complications of high uric acid levels.
Kidney Stone Formation
Abnormal urine levels of calcium, oxalate, cystine and uric acid are commonly linked to kidney stone formation. At high concentrations, these substances begin to form crystals that can enlarge and combine to become stones. These solid masses of crystals can then lodge in the kidney or lower urinary tract, causing severe abdominal or back pain, blood in the urine, fever, chills or nausea. Whether a stone passes naturally or requires a medical procedure for removal, all stone material should be submitted for chemical analysis. Knowing the chemical composition of a stone helps guide treatment and indicates what preventive steps might be indicated.
Uric Acid Stones
Your body produces uric acid during the normal turnover of tissue cells and when breaking down foods containing purine. Levels of uric acid in your blood rise during times of increased cell breakdown, as with chemotherapy or rapid weight loss and in certain genetic conditions and kidney disorders. High uric acid levels, or hyperuricemia, can lead to gout, kidney damage and kidney stone formation. Your kidneys excrete uric acid in the urine, and high blood levels result in higher urine concentrations with increased likelihood of stone formation. When a medical workup for kidney stones reveals uric acid stones, or laboratory measurement reveals elevated uric acid in your urine, you can take specific steps to decrease the risk of stones recurring.
Foods High in Purine
Purine-rich, high-protein foods increase your body's uric acid production and the amount of uric acid your kidneys must excrete. If your kidney stone contains uric acid, your health care practitioner will likely advise avoiding high-purine food sources. Sardines and anchovies, organ meats, bacon, scallops and shrimp, veal, venison and brewer's or baker's yeast used as a supplement are all high-purine foods. Red meat, poultry, pork, fish, asparagus, dried beans and spinach are moderately high in purine as well. Limiting these foods in your diet can help lower the uric acid level in your urine and the likelihood of more stones forming.
Additional Preventive Steps
Dehydration leads to higher concentrations of excreted substances in your urine, including those linked to kidney stones, making dehydration the major risk factor for kidney stone formation. Drinking 8 to 12 cups of fluid daily will help keep uric acid concentrations lower by adding more volume to your urine. Limit alcohol use also, because alcohol increases uric acid blood levels and can lead to dehydration, both of which contribute to stone formation. Finally, losing weight might reduce your risk, but be sure to do so gradually, as rapid weight loss can temporarily increase your body's uric acid production.
