Diet may help reduce kidney stones

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If you drink lots of orange juice and cut back on your salt intake, you may reduce your risk for kidney stones, says the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDKD).

More than a million cases of kidney stones are diagnosed each year, according to an NIH Healthline report and the pain they cause is agonizing. Kidney (and urinary tract) stones are hard masses composed of salts and minerals, such as calcium oxalate and calcium phosphate, that build up gradually over time. As the stone breaks away from the kidney and moves down the urinary tract, patients experience sharp, stabbing spasms.

Kidney stones are particularly unpleasant for males, who feel excruciating pain in the testicles as the hard mass slides slowly down and to the outside world. Yet, like so many human ills, appropriate dietary choices may help avoid later costly or unpleasant drug or surgical therapies. This is because what a person eats and drinks affects the chemical composition of the urine, either fostering or inhibiting kidney stones, according to NIDDKD-sponsored research.

In one study, 14 healthy men and women were maintained for 10 days on a high-sodium diet (143 grams a day) and on a low-sodium diet daily (2.9 grams daily) for the same period. The risk of a high-sodium diet can be seen by comparing the chemical composition of the two urine samples, according to Khashayar Sakhafe of the University of Texas Southwestern Medical center in Dallas and his colleagues. As they expressed it in scientific terms in the August 1993 issue of The Journal of Urology:

"In summary, a high-sodium intake increases the potential risk for kidney stone formation by elevating urinary saturation of calcium phosphate and monosodium rate, and decreasing the inhibitor activity against calcium oxalate crystallization by lowering the urinary citrate excretion."

In this framework, why would drinking orange juice or other citrus-based fruit juices, such as grapefruit, cranberry and grape, also produce a more desirable urinary mixture of chemicals?

In a related Center study published in the Journal of Urology of June 1993, eight healthy men and three men with a history of kidney stones each drank a quart, or about four glasses, of orange juice a day. Orange juice is rich in potassium and citrate. Significantly, potassium citrate is commonly used to prevent kidney stones. Thus, Cindy L. Wabner of Charles Y.C. Pak, M.D., discovered that when the men drank orange juice, their urine also had higher levels of the protective citrate.

According to Pak, although orange juice is less effective than the potassium citrate drug in preventing kidney stones, the natural product may be preferable for some people. NIH Healthline quotes him as saying:

"A few people can't tolerate the drug potassium citrate because of its gastrointestinal side effects. In these cases orange juice is a pretty good substitute."

Clinicians also find that some patients are more likely to comply with "alkaline therapy" in the form of a delicious natural drink. A side benefit, of course, is the well-known healthful properties of citrus juices.

PHOTO: Photo of Edith Kermit Roosevelt

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By Edith Kermit Roosevelt

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