Kidney stones? Pass the cranberry juice.

MRC News

For many years cranberry juice has been a popular folk remedy for many ills - including kidney stones. MRC-supported researchers show that it is more than a tasty drink...

Kidney stones are a painful reality many people have to live with. Approximately 10 - 15% of the general population suffers from the ailment at some stage or another. The root of the uncomfortable problem is calcium oxalate crystals which form in the urine and then progress through the spaghetti-thin tubes of the urinary tract. The result: excruciating pain.

Studies done by Prof. Allan Rodgers at the University of Cape Town scientifically prove that cranberry juice is an effective cure - not only a tasty folk remedy. The reason? The juice alters three key urinary risk factors: it lowers the concentration of oxalate and phosphate, it increases the citrate concentration and it dilutes the concentration of calcium oxalate in the urine. These results were published in the British Journal of Urology.

Previous studies had shown high concentrations of oxalate and calcium oxalate in the urine to contribute to crystal formation. It was also shown that citrate inhibits the formation of crystals - therefore the higher the citrate concentration in the urine, the better.

The Cape Town results add to studies published in the Journal of the American Medical Association and the New England Journal of Medicine. They found that cranberry juice had some anti- bacterial properties, which is important because it has recently been suggested that calcium-based stones may have an infectious origin. The results also state that some components occurring naturally in the berries may prevent the attachment of calcium oxalate crystals and stone-promoting bacteria to the epithelial cells in the renal tubes.


September 2004