Prevention of Kidney Stones

Urinary stones can be managed with non-invasive techniques such as extra-corporeal shockwave lithotripsy (ESWL) or minimally invasive surgeries. Endourology is the branch of urology that deals with minimally invasive surgical procedures. Using fine instruments, virtually all parts of the urinary tract is accessible and stone can be treated in this manner.

Prevention of kidney stones

A significant number of patients who have had kidney or urinary stones in the past form new stones again.  As high as 50% experience stone recurrence within 10 years.  The following dietary measures, among others, are helpful in preventing or decreasing the risks of kidney stone formation.

1) Increase fluid intake

The general recommendation of intake is at least 2 litres of fluids a day.  Increased fluid intake leads to increased urine production and it is the production of dilute urine that is important.

Water is adequate but fluids rich in citrate e.g. lemonade are also helpful

2) Adequate calcium intake

It is a common misconception that calcium intake should be restricted.  Calcium binds with oxalate in the intestines, thereby reducing absorption of oxalates.  This in turn reduces the risk of stone formation.  In fact low-calcium diet can lead to increased risk of stone formation and conversely, adequate calcium intake can lead to lower kidney stone formation rate.

3) Limit sodium intake

Sodium competes with calcium for reabsorption in the kidneys.  With high sodium content, less calcium is reabsorbed, leading to higher excretion of calcium in the urine and hence stone formation.

4) Limit foods with high oxalate content

Oxalate is excreted in the urine and its concentration is critical to stone formation.  Foods with high oxalate contents include nuts, spinach and rhubarb.

Vitamin is a precursor of oxalate produced in the body.  Increased intake of Vitamin C will lead to higher levels of oxalate.  It is recommended limiting to 1000 mg of Vitamin C per day.

5) Limit foods with high animal protein

Excess animal protein may lead to high uric acid levels resulting in formation of uric acid stones.  Furthermore, lower animal protein can result in lower excretion of calcium and increased excretion of citrate in the kidneys.