Red meat, organ meats, and shellfish have high amounts of a natural chemical compound known as purines. High purine intake leads to a higher production of uric acid and a larger acid load for the kidneys to excrete. Higher uric acid excretion leads to more acidic urine. The high acid concentration of the urine makes it easier for uric acid stones to form.
To prevent uric acid stones, cut down on high-purine foods such as red meat, organ meats, beer/alcoholic beverages, meat-based gravies, sardines, anchovies and shellfish. Follow a healthy diet plan that has mostly vegetables and fruits, whole grains, and low-fat dairy products. Limit sugar-sweetened foods and drinks, especially those that have high fructose corn syrup.
Limit alcohol because it can increase uric acid levels in the blood and avoid short term diets for the same reason. Decreasing animal-based protein and eating more fruits and vegetables will help decrease urine acidity and this may help reduce the chance for uric acid stone formation.
(Source: US National Kidney Foundation)