Kidney stones are one of the most common disorders of the urinary tract, and they are growing more common. The National Kidney Foundation reports that kidney stones affect one in 11 people in the U.S. each year, an increase over the one in 20 they affected in 1994. More than a million people visit their health care provider and another 300,000 people go to the emergency room for kidney stone problems each year.
The formation of kidney stones, or urolithiasis, usually results from minerals in the urine that combine to form crystals. If the crystals grow large enough, they may block the ureters, preventing urine from passing freely and disrupting kidney function. Symptoms can come on suddenly and include:
- Severe pain in the abdomen or lower back
- Nausea and vomiting
- Frequent, painful urination
- Blood in the urine
"It's important to seek medical care if you're having documented fever, you see blood in your urine or you have uncontrolled pain,” said Jill Bloom, P.A.-C. with Carilion Clinic Urology. “You'll likely need to have your urine checked; labs and imaging are often also warranted. Medications can often be given to help pass some stones."
Rarely, kidney stones are the result of a genetic disorder (cystine stones) or kidney infections (struvite stones). But the most common types of stones—calcium-oxalate stones and uric acid stones—form directly from dietary minerals. The National Kidney Foundation offers the following tips to avoid kidney stones:
Sweat caused by exertion or even just the summer heat results in decreased urine production. The more you sweat, the less you urinate. This allows more minerals to settle and bond in the kidneys and urinary tract. Drink plenty of water so that you urinate often.
Be Mindful of Minerals
Calcium-oxalate stones are the most common type of kidney stone people tend to produce. The two minerals bind together and form stones in your kidneys as you produce urine.
Calcium is found in dairy products, leafy greens and seafood. Oxalate is found in fruits and vegetables, nuts and seeds, grains, legumes, chocolate and tea.
These foods provide important nutrients and can otherwise be part of a healthy diet, so rather than avoid them, people who form these stones are advised to eat and drink them together instead of at separate meals. This allows the two minerals to bind in the stomach and intestines before the kidneys begin processing, making it less likely for kidney stones to form.
Spare the Salt
Sodium causes the kidneys to excrete more calcium into the urine, and the average American consumes much more sodium (3,400 milligrams) than the U.S. recommended dietary allowance (RDA) allows (2,300 milligrams). The National Institute of Diabetes and Digestive and Kidney Diseases recommends that people who form kidney stones limit their sodium intake to the U.S. RDA even if they take medications to prevent kidney stones.
Switch From Sweet to Tart
Potassium citrate reduces the potential for kidney stone formation by preventing calcium from crystallizing. Lemonade, limeade and other fruits and juices high in natural citrate offers the same prevention benefits as the potassium citrate used by medical providers to treat chronic kidney stones. So enjoy a glass of fresh lemonade. Limit the sugar and high fructose corn syrup, though, as they can increase kidney stone risk.
Uric acid stones are the result of high purine intake. Cutting down on red meats, organ meats and shellfish will reduce the purine in your kidneys. Alcohol has the same effect, so limit that as well. Overall, eating less animal-based protein and eating more fruits and vegetables will help decrease urine acidity, reducing the chance for stones to form.
According to Bloom, people who have had stones have a 90-percent chance of developing another stone within 10 years if they make no dietary or other lifestyle changes. In the absence of metabolic abnormalities, which can be determined by a urine test and treated with medication, diet and lifestyle changes are the key factor in preventing recurrence.
“If you're able to increase your urine output to over 2.5 liters per day, cut back on the intake of oxalates, monitor your sodium and protein intake and maintain a healthy weight, you may be able to decrease your risk,” she said.