Ten years ago, Alicia Neu, M.D., almost never encountered a child with kidney stones. Today, the co-director of the kidney stone clinic at Johns Hopkins Children's Center says she sees several per month. Colleagues across the country have noticed a similar increase in their caseloads.
"We're seeing more and more kids with stones, and we're starting to track it," Neu says.
Modern ultrasound and CT scanners are now able to detect even the tiniest kidney stones, and that could account for some of the increase in diagnoses. But experts suspect that children's diets deserve the larger share of the blame. Kids just take in too much salt and too little water.
What Are Kidney Stones?
Kidney stones form when the urine becomes too concentrated with a certain substance, such as calcium or uric acid. The substance forms crystals that come together to create "stones," which are usually just a few millimeters across. When these stones pass into the ureter - the tube that carries urine from the kidneys to the bladder - they can cause nausea, blood in the urine, and pain in the abdomen, stomach and back. Most stones pass from the body on their own, but this is painful enough to require treatment with pain medication. Stones too large to pass on their own can block the urinary tract, causing injury or infection. These may need to be surgically removed.
One key to preventing kidney stones is fluid intake. Drinking at least 64 ounces of water per day, Neu explains, dilutes the urine so that stones do not form. It's easy for kids to tell if they're drinking enough, she says. "They should feel like they have to go to the bathroom every two to three hours."
Since sugar-sweetened beverages like soda or juice make up most of many children's daily beverage intake, parents should gradually reduce intake of these while increasing the amount of water a child drinks, according to Sarah Letos, M.S., R.D., senior pediatric clinical dietician at the Johns Hopkins Children's Center. Sending a water bottle to school can help. For kids who don't like the blandness of water, Letos recommends diluting a sports drink or other favorite beverage with half water, or trying one of the many flavored waters on the market.
Keep the Salt Down
Also important is keeping sodium intake below 2,000 milligrams per day, because a high-salt diet is known to contribute to the formation of calcium stones, the kind most commonly seen in kids.
"I think kids' diets continue to get worse," says Letos. But she is quick to add that few of us drink enough water, and most of us take in too much sodium. So this is a project for the whole family.
The easiest way for most families to cut sodium is in their choice of fast foods and convenience foods - many of which pack a whole day's worth of salt into one meal. Fresh foods - those that don't come in packages - usually contain almost no sodium, Letos says.
Improving the family diet doesn't have to mean giving up all of the things you like to eat. Letos recommends reading the labels of packaged foods, such as rice mixes or frozen entrees, and changing brands if you find one lower in sodium. If you eat fast food, request the nutrition information at the restaurant and make lower-salt choices, or change restaurants if you find lower-sodium offerings at a different chain.
Even when you're choosing among salty snacks, it pays to read the label. "It's amazing how much sodium you can cut out by just changing brands sometimes, or even flavors," Letos says. The salt-and-vinegar potato chips, for instance, could contain more salt than the barbecue style.
"It is definitely possible to make changes for the better," Letos insists, "and it doesn't have to be a bad thing for families."
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