The Hard Facts on Avoiding Kidney Stones

How to keep from developing this painful problem

illustration by emma moreman

In an unfortunate, six-degrees-of-Kevin-Bacon sort of way, everyone seems to know someone who has had kidney stones. Those who have had first-hand experience with the common urinary tract disorder would probably say it is an experience they wouldn’t wish on their worst enemy.

Excruciating pain can accompany kidney stones; some say the pain rivals that of breaking a leg or giving birth. Depending on the size and location of the stones, the disorder might bring achiness or pain in the back or abdomen, an increased urgency to urinate, pain with urination, or blood in the urine. While it is possible to pass a kidney stone with only mild symptoms and to pass stones with minimal medical intervention, “very few can pass without pain,” says Matthew Stanizzi, MD, a urologist at Southern New Hampshire Medical Center in Nashua. The worst cases require surgery.

The incidence of kidney stones is on the rise, with women, children and African Americans today more likely to develop stones than in the past. The increasing occurrence of stones possibly reflects lifestyle changes — such as poor eating habits and obesity — that do not bode well for overall health. “The things that lead to a less-healthy lifestyle,” Stanizzi says, “help propagate kidney stones.”

Kidney stones develop when minerals in the body bind together and crystallize. The hard deposits can be as small as a grain of sand or as large, Stanizzi says, as several golf balls clumped together, and they form when urine is too concentrated. A number of factors can lead to overly concentrated urine, but “the root cause,” Stanizzi says, “is always too little water and too much of the stuff that forms stones.”

Calcium, oxalate and uric acid are most commonly involved in stone formation, and a personal or family history of stones makes you more likely to develop them. Those who face an elevated risk of developing stones are typically advised to limit calcium supplements (stone problems related to calcium most often appear to be linked with calcium supplements as opposed to diet-based calcium), oxalate-rich foods such as leafy greens and meat, certain nuts and chocolate. To reduce the risk of kidney stones, most “stone formers” don’t need to completely deprive themselves of certain foods, but instead follow the “everything in moderation” maxim, says Steven Kahan, MD, JD, a urologist at Atlantic Urology Associates, Core Physicians, located in Portsmouth and Exeter. And tolerance of foods is different for each of us. If you’ve reached middle age and routinely eat, say, spinach salad without incident, Kahan says, then that food is probably not a problem for you.

Genetic predisposition — coupled with dietary habits — likely plays a role in most instances of kidney stones, Stanizzi says. The kidneys of people who do not develop kidney stones are probably wired so they can handle the calcium, oxalate, and food that can create stones in other people, Stanizzi says. Some individuals might be “on the edge” of predisposition, he says, and develop stones when they happen to get dehydrated and eat the wrong kind of food.

For everyone, staying hydrated is typically a cornerstone of kidney stone prevention and treatment. “If you do nothing else but stay well-hydrated, then the battle is half won,” Stanizzi says, “versus if you don’t stay well-hydrated and you do everything else to a ‘T’ you can still develop stones.”