Tips for lowering your risk of kidney stones
By Dr. Peter Sawaya
University of Kentucky
Kidney stones are common. In the United States, one in 11 individuals will be affected by them at some point in their life.
Kidney stones are typically seen in adults between 40 and 60 years old. However, they can form at any age and at any time of year. Nearly half of those who develop one kidney stone in their lifetime will develop at least another stone in the future.
What are kidney stones? Kidney stones are made from large deposits of undissolved minerals and other organic compounds as they get supersaturated and crystallize in the urine. Calcium oxalate stones are the most common, then calcium phosphate and uric acid.
When urine has too many of these crystal-forming substances and not enough liquid, they accumulate to form a hard, stone-like piece of material that can range between the size of a grain of sand to a golf ball. These stones may travel down the urinary tract and get “stuck,” blocking urine flow and potentially causing kidney swelling.
How to lower your kidney stone risk: The most effective and easiest way to prevent kidney stones is simple: Drink plenty of water to produce at least 2.5 liters (80-90 ounces) of urine per day.
Stay well hydrated all year round, especially during those steamy Kentucky summers and when engaged in sweat-inducing activities like exercise or working in the yard.
Lemonade or fluid containing citric acid is a good addition to the water, as citrate inhibits crystal formation. Dark soda and fructose-containing fluid increase your risk of stones and should be avoided.
While most stones have calcium in them, eating food rich in calcium — like leafy green vegetables and dairy products — can actually be beneficial for you. The calcium in these foods binds to oxalate in your intestines and lowers the amount of oxalate that eventually makes its way to the kidneys.
Lowering your intake of sodium, often present in processed meat, high doses of vitamin C and oxalate-rich food, like dark chocolate and spinach, can also lower your kidney stone risk.
(Editor’s note: Oxalate is a natural substance found in many foods, according to the National Kidney Foundation.)
What symptoms should I look out for? Symptoms may not be noticeable until the stone moves inside the kidney or makes its way to the ureter, the tube connecting the kidney and bladder.
Common symptoms include:
- Severe pain in the side and back, below the ribs
- Pain that radiates to the lower abdomen and groin
- Pain that comes in waves and fluctuates in intensity
- Pain during urination
- Pink, red or brown urine
- Cloudy or foul-smelling urine, if infected
- Nausea and vomiting
- Persistent need to urinate
- Fever and chills if an infection is present
Inform your doctor if you’ve passed a kidney stone or have any of the above symptoms. Seek immediate medical attention if you experience pain accompanied by nausea or fever, pain so severe you can’t sit in a comfortable position or if you see blood in your urine.
This week’s column is by Dr. Peter Sawaya, chief of UK HealthCare’s division of Nephrology, Bone and Mineral Metabolism.