Prevention

Formation :: Stone Types :: Diagnosis
Treatment :: Prevention :: Kidney Stone Info Sheet

Without changes being made, a recurrent stone episode will occur in 50% of patients within 10 years. General measures in kidney stone prevention revolve around maintaining a healthy lifestyle and normal weight, keeping up fluid intake, reducing animal protein intake and decreasing salt in the diet.

There is no evidence restricting calcium intake reduces kidney stones from developing. Unless there is a specific abnormality detected through blood tests, calcium stones are not normally due a calcium excess. Calcium is important in maintaining bone health and especially guarding against osteoporosis in the older age groups. Sometimes restricting dietary calcium can actually increase the risk of developing calcium stones in the kidney as it allows other stone forming minerals to be preferentially absorbed into the body from the gut. The recommended daily requirement of calcium is 1000 mg, and two-thirds is consumed in dairy containing products. You are encouraged to consume two servings of dairy (but no more than two) or other calcium-rich food per day to maintain normal bone stores of calcium.

The best method to prevent stone formation is to drink more fluids, thereby diluting your urine. Fluid intake needs to be increased to 8 to 10 glasses (2.5L) in a 24 hour period. Ideal fluids include water, citrus juices and carbonated mineral water beverages. This needs to be spaced evenly throughout the day, and a practical measure is to carry a drink bottle at all times. Even more oral fluids need to be consumed on hotter days due to insensible losses from perspiration (sweating). A good measure of success is the colour of the urine should be clear or a very pale yellow.

Reducing Protein Intake

Excessive protein intake can result in uric acid stones. An important goal is to stay within a healthy weight range. As a general recommendation, limit your daily intake to 350 grams per day in total of beef, poultry, fish and pork. This will easily provide enough protein for the body’s daily requirements. An easy rule of thumb for estimating portion size is 100 grams of meat is roughly the size to cover the palm on your hand.

Decrease Salt Intake

The human body carefully regulates its sodium levels. When excess sodium is excreted in the urine, calcium is also excreted proportionally. In other words, the more sodium you take in and excrete, the more calcium you waste in the urine. Excess calcium in the urine can lead to new stone formation. Try to reduce dietary sources of sodium, including fast foods, packaged or canned foods, and salty snacks. Your goal should be to consume less than 2000 mg/ day of sodium. This is equivalent to one teaspoon of salt per day.

If stones are due to uric acid crystal formation, prevention can be achieved by making the urine less acidic (pH>7) or decreasing uric acid production. This can be achieved by alkalinizing the urine using oral bicarbonate preparations (over the counter medication), and/or oral prescription medication (allopurinol) to prevent excessive uric acid production. Infection stones require complete stone removal and ongoing prevention against further urinary tract infections.

Cystine stones require lifelong close medical surveillance and an individualised treatment programme.