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If you've ever had a kidney stone or driven someone to the ER who did, you know the pain can be horrific. There are surgical interventions to treat them but when it comes to preventing kidney stones, a new study shows that a certain pattern of eating seems to significantly reduce the risk.
NPR's Allison Aubrey reports.
ALLISON AUBREY: Physician David Goldfarb says he's part of the kidney stone sufferers club. He had his first attack in his late 20s, decades ago, but he remembers it as if it were yesterday.
Dr. DAVID GOLDFARB (Nephrologist, New York University): At about 8:30 in the morning, I was walking down the street when I was suddenly accosted by this tremendous pain. It felt like a large chef's knife had been stuck in my back, and I was sort of doubled over and soaked through my clothes, sweating.
AUBREY: A dramatic day in the ER followed. But once the stone passed, he says, like most people, he didn't take any steps to prevent the next one.
Dr. GOLDFARB: And most people with relatively small stones that pass the stone in the emergency room, as I did, forget about it, don't follow a diet, don't drink more water. And that's why kidney stones are so recurrent.
AUBREY: After his second attack, Goldfarb says he began drinking lots and lots of fluids. To this day, he says he drinks coffee all morning and keeps a water bottle in hand as he sees patients. This strategy has really helped him. And he says when it comes to diet, it turns out there's new evidence that eating calcium-rich foods, such as low-fat milk and yogurt, can be helpful.
Now, researchers point out that since kidney stones are formed out of calcium, at least partially, it may seem odd that eating lots of it actually inhibits the development of kidney stones.
Dr. ERIC TAYLOR (Kidney Specialist, Brigham and Women's Hospital): It is a little bit counterintuitive, maybe, that actually higher intakes of dietary calcium are associated with a reduction in kidney stone risk.
AUBREY: That's kidney specialist Eric Taylor. He's a researcher at the Channing Laboratory at Brigham and Women's Hospital in Boston.
And he explains what seems to be happening in the body is that all the calcium in foods bind with a waste product in the gut called oxalate. The two substances stick together, crystallize, and then exit the body long before there's a chance to form kidney stones.
So just how effective is diet in helping prevent stones? Taylor's most recent study offers some of the best evidence yet.
He analyzed the diets of about 3,500 people with and without kidney stones. And he was particularly interested in those who followed a certain pattern of eating, similar to the Mediterranean diet.
Dr. TAYLOR: So higher intake of fruits, vegetables, nuts and legumes; low-fat dairy and whole grains; and a low intake of sweetened beverages, and red and processed meats.
AUBREY: Taylor says those who adhered most to this pattern of eating were significantly less likely to develop kidney stones.
Dr. TAYLOR: We found a decrease in risk in the order of around 40 or 45 percent. We were very excited by it.
AUBREY: None of this is an assurance that people prone to kidney stones will be able to prevent them through diet alone. But experts say it's one more strategy that could help.
Allison Aubrey, NPR News.
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