THE CLAIM
Fruit juice can prevent kidney stones.
THE FACTS
Kidney stones strike more than a million people every year, sometimes causing enough pain to bring them literally to their knees. Along with medication patients are often encouraged to make dietary changes, including drinking more citrus juices. Citrate reduces the formation of calcium oxalate stones and lowers urine acidity. But not all juices have the same effect.
Lemonade is the usual recommendation for people with stones. But a 2006 study compared lemonade with orange juice and found that three cups of orange juice a day, along with other dietary changes, did a better job of raising citrate levels. Then there are cranberry and apple juices, which, according to studies. are good for some stones and bad for others. They raise the recurrence risk of calcium stones, but help prevent a far less common subset of kidney stones called brushite.
THE BOTTOM LINE
Some fruit juices protect against kidney stones; others raise the risk.