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Lots of water, small dietary changes can help prevent kidney stones, UTSW expert says

Scans showing a renal stone (pink), or nephrolithiasis, in the right kidney
Scans show a kidney stone (pink) in the right kidney of a patient. More than a half-million people in the U.S. visit hospital emergency rooms each year for kidney stone treatment, and 1 in 10 will develop one during their lifetime. (Photo credit: Getty Images)

DALLAS – June 12, 2023 – The painful experience of having a kidney stone has become more common in recent years, including in Texas, part of the “Stone Belt” where hot weather can cause dehydration. But small dietary changes as well as drinking lots of water can help avert the discomfort, says a board-certified physician assistant in the Department of Urology at UT Southwestern Medical Center.

“Once you’ve had one stone, you have up to a 50% chance of having another within the next 10 years,” said Megan Bollner, M.P.A.S., PA-C. “But many risk factors for recurring kidney stones are within your control, and changing your eating habits can make a big difference.”

Megan Bollner, M.P.A.S., PA-C
Megan Bollner, M.P.A.S., PA-C, is a board-certified physician assistant in the Department of Urology at UT Southwestern.

Kidney stones are formed by crystals and can block the flow of urine as it leaves the kidneys through the ureters, the tubes that carry urine to the bladder. The stones can form from a variety of minerals, but the most common type is calcium oxalate. They’re more likely to develop in highly concentrated urine, which can appear dark yellow instead of clear or straw-colored.

Stones often start out the size of a grain of sand but can grow to fill the inside of a kidney. And the larger they are, the more difficult or even impossible passing them becomes.

According to the National Kidney Foundation, more than a half-million people visit U.S. hospital emergency rooms annually for kidney stone treatment, and 1 in 10 will have one during their lifetime. Men have a slightly higher risk of developing them.

Recurrent stone formation can result from factors including family history, underlying kidney disease, obesity, diabetes, dietary choices, chronic dehydration, and inflammatory bowel disease. Symptoms can include severe one-sided lower back pain, nausea, vomiting, fever, chills, and bloody urine. Kidney stones also can be asymptomatic.

Ms. Bollner’s No. 1 recommendation for preventing the recurrence of stones may be the simplest: Drink more fluids to stay hydrated, which dilutes urine so crystals can’t clump into stones.

People who have had a kidney stone should drink at least 2 liters (8 cups) and ideally 3 liters (12 cups) of water per day. When it’s hot outside or if you work in a hot environment, you should drink even more water because the more you sweat, the less urine you produce. Adding citrus juice, such as lemon or lime, to water can be helpful because it contains citrate, which binds to calcium to help block stone formation.

Here are other suggestions from Ms. Bollner:

Limit sodium intake: A high-sodium diet increases the amount of calcium in urine, which can trigger kidney stones in people who are susceptible. Follow federal guidelines that recommend limiting sodium to 2,300 milligrams daily – equal to about 1 tablespoon. Reducing salt also benefits the kidneys by helping reduce blood pressure, since chronic high blood pressure can narrow and weaken blood vessels, affecting blood flow and potentially leading to kidney disease or kidney failure.

Eat calcium-rich foods: It may seem counterintuitive to recommend calcium when most kidney stones are partially composed of calcium. However, taking in a normal amount of calcium is critical to the body’s calcium regulation. Also, calcium from food combines with oxalates in the intestines, forcing oxalates into the feces instead of the urine and reducing the risk of developing calcium oxalate stones. For the best results, consume 1,000-1,200 milligrams of calcium a day from dairy, soy, beans, fortified tofu, and green vegetables such as kale and broccoli.

Cut back on meat: Eating too much animal protein can increase your risk of developing stones. This includes not only red meat, but also chicken, pork, fish, and even eggs. Limit meat intake to 8 ounces a day.

Eat plenty of fruits and vegetables: This can help prevent the formation of stones by increasing urinary citrate, the naturally occurring acid that keeps calcium from sticking together in urine and forming stones.

Monitor oxalate intake: Oxalate is found in many healthy foods, such as spinach, beets, nuts, wheat germ, rhubarb, and soy, but it also can contribute to kidney stone formation. While it is unlikely for oxalate consumption alone to cause stones, excessive amounts of oxalates can greatly increase the risk. Eat a varied diet and drink extra water or eat a serving of dairy when you consume foods high in oxalate.

UT Southwestern’s Department of Urology is ranked No. 11 in the nation by U.S. News & World Report for the diagnosis and treatment of urologic diseases.

About UT Southwestern Medical Center  

UT Southwestern, one of the nation’s premier academic medical centers, integrates pioneering biomedical research with exceptional clinical care and education. The institution’s faculty has received six Nobel Prizes, and includes 26 members of the National Academy of Sciences, 19 members of the National Academy of Medicine, and 14 Howard Hughes Medical Institute Investigators. The full-time faculty of more than 2,900 is responsible for groundbreaking medical advances and is committed to translating science-driven research quickly to new clinical treatments. UT Southwestern physicians provide care in more than 80 specialties to more than 100,000 hospitalized patients, more than 360,000 emergency room cases, and oversee nearly 4 million outpatient visits a year.