Urinary tract calculi (e.g., kidney stones) are a common condition plaguing mankind. The incidence of urinary calculi is increasing steadily in Western civilization. This is due to a combination of the Western diet and lifestyle. The peak incidence of urinary tract calculi is the third through sixth decades of life. If someone has a family history of urinary tract calculi, they are three times more likely to develop a renal or ureteral stone. There is an increased risk of developing stones with increasing weight. As obesity becomes more common in the United States, the incidence of urinary tract calculi has also increased.

After someone has had a kidney stone and has successfully passed it or had it surgically removed, the treatment of the patient is not complete. Along with removing a stone or helping a patient to pass a stone spontaneously, treatment also consists of modifying the patient’s diet and lifestyle to decrease the possibility of recurrent stones in the future. If no changes are made in the diet or lifestyle, the recurrence rate after a first stone is 20% at one year, 60% at five years, and 80% at ten years.

Certain recommendations are made for all patients regardless of the underlying etiology of their stone disease. The most important of these conservative measures is to have the patient increase their fluid intake in order to maintain a urine output of greater than two liters per day. Over a 24-hour period, when it is convenient for the patient, they should measure their urinary output. The simplest manner to do this is to fill a two liter soda bottle with urine. This should be monitored every three months by the patient to ensure a consistent urinary output in each season.

All patients with a history of stone disease should limit their salt intake. Increased salt intake causes an increase in urinary calcium, which is a risk factor for urinary stones. Protein intake should also be limited. Vegetarians have the lowest incidence of stone disease and patients on high protein diets have the highest incidence of stone disease. In the past, patients suffering from stone disease have been told to limit their calcium intake; however, new studies suggest that a normal calcium intake is beneficial for a patient with stone disease. Questions always arise in women who have been advised to take calcium supplementation to prevent osteoporosis. Calcium supplements appear to increase the risk of stone disease in the first three months of initiation of therapy. Thereafter, the risk of stones returns to a normal level.

Since 80% of stones are composed of calcium oxalate, it is also helpful to limit a patient’s intake of high oxalate foods. These foods consist of spinach and other leafy green vegetables, tea, chocolate, nuts, peanut butter and cola drinks.

A patient should also try to increase their intake of lemonade and orange juice as these fruits contain citrate. An increased urinary citrate lowers the urinary saturation of calcium salts. An easy way for a patient to increase their citrate intake is to place 120 cc of real lemon juice in a two-liter container and then fill the container to a volume of two liters with tap water.

Lifestyle changes are also important. Patients who gain weight or are obese have a higher incidence of stone disease than patients at their ideal weight or patients who lose weight. Patients who have a sedentary lifestyle are at higher risk of stone disease than patients who exercise regularly.

It is anticipated, with these conservative measures to correct dietary and lifestyle risk factors, a significant number of patients may be able to normalize their risk factors for stone formation. If patients can make these changes permanent, no other therapy will be required in the majority of patients with stone disease. It is helpful to follow these patients, not only to monitor the efficacy of treatment, but also to encourage patients to continue their compliance with these changes. If a second stone reoccurs despite these changes, a more in-depth metabolic stone evaluation may be considered.