Fighting kidney stones

Kidney stones are solids that form in the kidneys when substances like calcium, oxalate and phosphorus, normally excreted through urine, become concentrated. A kidney stone may settle down in the kidneys or travel right through the urinary tract. The symptoms vary depending on its size.

A smaller crystal may comfortably travel down the urinary tract and get expelled on its own without causing any pain or discomfort. Passing a bigger kidney stone can be a very painful experience and, depending on size and location, you may need anything from pain medication to surgery. Surgery is usually done if stones become lodged in the urinary tract or cause complications.

There are several factors that predispose an individual to kidney stones. The most common include a family history of kidney stones, repeated urinary tract infections or a blocked urinary tract. Insufficient intake of water and certain medications can also cause kidney stones. If you’ve had kidney stones in the past, these guidelines will also help you reduce the risk of recurrence.

Lifestyle changes

There are different types of kidney stones: calcium oxalate, calcium phosphate, uric acid, cystine and struvite. Calcium oxalate stones are the most common. Each type requires different nutrition and lifestyle change advice. So it’s best to first get the stones analysed.

If you’re looking at prevention, one sure-shot way to reduce the risk is to drink water throughout the day.

Aim for at least two and a half to three litres of fluid each day. People with cystine stones may want to aim at drinking even more water.

If you are not used to drinking this much fluid, start by adding one extra glass each day and slowly increase the number of glasses you have.

Sugary drinks, like aerated drinks and coffee and tea, are not good choices for increasing the amount of fluid you drink. For they may increase your risk of kidney stones.

One practical way of finding out if you are drinking enough water is to check the colour of your urine. If it is deep yellow, you need to up the water intake.

Don’t hold your urine for long, and don’t underestimate loss of fluids through sweat. The more you sweat, the less you urinate, and that can cause minerals to settle in the urinary passage and cause stones.

Choose a diet low in salt

Reduce animal protein

If you have the commonest, calcium oxalate stone, you don’t need to restrict the calcium in your food. Continue eating calcium-rich food, but take calcium supplements only if prescribed by a doctor. Eat less oxalate-rich foods such as beets, broccoli, okra, spinach, sweet potatoes, nuts, black tea, tomatoes, chocolate, soy products, wheat bran and buckwheat.

If you want to take a vitamin C supplement, make sure you take less than 1,000mg per day. A high amount of vitamin C can, in fact, increase your risk of stones.

If you have a uric acid stone, avoid red meat, organ meats and shellfish, which have high concentrations of purines. High purine intake leads to a higher production of uric acid, and the kidneys have to work harder to excrete it. Higher uric acid excretion leads to lower urine pH, which basically means the urine is more acidic—a friendlier environment for uric acid stones.

Apart from limiting the foods mentioned above, also restrict sugar-sweetened foods and drinks, especially those that contain high fructose corn syrup. Consume alcohol in moderation because it can increase uric acid levels in the blood. Eating less animal-based protein and more fruits and vegetables will help decrease urine acidity. This will, in turn, help reduce stone formation.

Vishakha Shivdasani is a Mumbai-based medical doctor with a fellowship in nutrition. She specializes in controlling diabetes, cholesterol and obesity.