Treating kidney stones: questions to ask your doctor

It seems amazing that something so tiny can cause so much suffering. But while a small minority of people are genetically destined to develop a kidney stone, you can probably greatly reduce your odds of getting one with some simple lifestyle changes. Here is a list of questions to ask your doctor regarding your kidney stones.

Logic might dictate that if excess calcium in the urine is a prime cause of kidney stones, then decreasing your calcium intake should reduce your risk of developing a stone. And indeed, many urologists instruct their patients to cut down on dairy products and other high-calcium foods. But it turns out that this may not be good advice.

In a clinical trial in Italy, 120 men with a history of calcium oxalate kidney stones (the most common type) were divided into two groups: one ate a low-calcium diet with average amounts of animal protein and sodium, while the other ate a normal-calcium diet with reduced meat and sodium. After five years, nearly twice as many men on the low-calcium diet had formed new stones compared with those on the normal-calcium diet.

There appeared to be two reasons for this: the low-calcium group had higher levels of urinary oxalates (and thus stones) because they didn't have enough calcium in their systems to bind (and thus render harmless) the oxalates. Those in this group also didn't cut down on meat and sodium, which promote stone formation.

What makes a person susceptible to kidney stones is not always clear, although a family history of this disorder makes you more prone to forming stones. In most cases, despite all sorts of diagnostic testing, doctors never find out why the stone appeared. What is known, however, is that if you pass one stone, you're more likely to have another. That statistic makes it important for you to have blood and urine tests, and, if possible, have the stone itself analyzed. This will arm you with what you need to know to help prevent a recurrence.

That depends on what type of kidney stones you have. If your urine chronically contains high levels of oxalate, you may well benefit from a change in your diet. But if your stone was not composed of calcium and oxalate combined, reducing oxalate consumption won't make much difference.

However, unlike cutting back on calcium (needed for healthy bones), ingesting less oxalate won't do much harm because by itself it doesn't have any nutritional value. Foods high in oxalate include spinach, strawberries, nuts, rhubarb, beets, soy products, tea, cola drinks, apple juice and cranberry juice.