Nutrition Management of Uric Acid Stones

Common risk factors for the formation of uric acid kidney stones include low urine volume, uricosuria, and low urinary pH of which low urinary pH is the most important risk factor. The primary treatment for uric acid stones involves alkalinizing the urine which alters the solubility of uric acid and its tendency to precipitate in an overly acidic environment. Nutrition intervention plays a secondary role in the management of stone disease; no studies have been conducted comparing pharmacotherapy to nutrition interventions. Dietary factors known to increase serum uric acid and the risk of gout, and evidence from epidemiological trials and studies utilizing stone registries have been used to support dietary measures. Limitations in the literature include: few well-controlled, randomized trials; studies of short duration; normal volunteers recruited instead of stone formers; dietary manipulations focused on multiple instead of single components such as protein; and outcome measurements assessing reduction in risk factors not actual stone formation or recurrence. Gender and age differences may affect stone risk as well. This chapter will examine the well-known factors contributing to stone formation as well as emerging epidemiological trends that may have implications for uric acid nephrolithiasis.