Kidney stones are among the most painful of urinary tract infections, and unfortunately, they’re not that uncommon. According to the federal National Kidney and Urologic Diseases Information Clearinghouse (NKUDIC), more than a million people yearly visit their health-care practitioners because of kidney stones, and an additional 300,000 people end up in emergency rooms.
The stones, which form in the kidneys when calcium combines with oxalate or phosphate, range in size from almost invisible to those that are impossible to pass via urination. Depending on their size, you might feel nothing when you expel them via urinating, or you may be in great pain. Stones can also lead to infection.
And according to the experts at Harvard Medical School, the condition, which is more common in men than women, recurs in 50 percent of cases within seven years if sufferers don’t take preventive steps.
Prevention isn’t complicated, the Harvard experts say, but it does require consistency. "It means drinking plenty of fluids and following a diet that is low in sodium, with limited animal protein and age-appropriate intake of calcium," Dr. Melanie Hoenig, an assistant professor of medicine at Harvard-affiliated Beth Israel Deaconess Medical Center, told the Harvard Men’s Health Watch newsletter. "Dietary changes are important, but it is difficult to stick with them every day."
To prevent kidney stones, you need to prevent the conditions that make stones more likely to form. Here are the most important steps:
The Harvard experts recommend these strategies:
Hydrate, hydrate, hydrate. That dilutes the substances that lead to stones. Drinking eight 8-ounce cups is ideal. You can also include citrus beverages, like orange juice. The citrate in them works to prevent stone formation.
Get enough calcium. Too little calcium can cause a rise in the levels of oxalate, which can lead to stone formation. But it’s best to get calcium from food, since some studies have linked the consumption of calcium supplements to a rise in kidney stones. Men who are 50 and older, the Harvard experts say, should get 1,000 milligrams (mg) of calcium per day, along with 800 to 1,000 international units (IU) of vitamin D so that the body can better absorb calcium. Foods that are rich in calcium include low-fat milk, low-fat yogurt, broccoli, green beans, tofu and sardines.
Cut back on salt. Too much salt can increase the calcium in urine. Although federal guidelines suggest limiting total daily salt intake to 2,300 milligrams, the Harvard doctors say you should reduce that to 1,500 milligrams if you’ve already had kidney stones that have been caused by sodium.
Avoid animal protein. Excessive meat, eggs and seafood can lead to kidney stones because it boosts levels of uric acid. The Harvard experts recommend restricting your animal protein consumption to a portion no bigger than a pack of cards. (It’s also a good heart-health strategy, they say.)
Steer clear of “bad” foods. Some foods, including beets, chocolate, spinach, rhubarb, tea, and even most nuts have high levels of oxalate, which can contribute to the formation of kidney stones. Another culprit: cola, which has high levels of another risky substance, phosphate. If you’ve already suffered from kidney stones, your doctor can tell you exactly which foods to avoid or cut back on.
If you’ve had at least one episode of kidney stones, Dr. Hoenig suggests a medical evaluation to see what caused them. A physician can provide you with dietary recommendations or medications, or may refer you to a specialized “stone clinic.”
For more information, subscribe to the Harvard Men’s Health Watch.