Researchers have found evidence that a natural fruit extract is capable of dissolving calcium oxalate crystals, the most common component of human kidney stones. This finding could lead to the first advance in the treatment of calcium oxalate stones in 30 years.

Jeffrey Rimer, associate professor of chemical engineering at the University of Houston, was lead author of the study, published Aug. 8 in the online edition of Nature. The work offers the first evidence that the compound hydroxycitrate (HCA) is an effective inhibitor of calcium oxalate crystal growth that, under certain conditions, is actually able to dissolve these crystals. Researchers also explain how it works.

Kidney stones are small, hard mineral deposits that form inside the kidneys, affecting up to 12 percent of men and seven percent of women. High blood pressure, diabetes and obesity can increase the risk, and the reported incidence is on the rise.

Preventive treatment has not changed much over the last three decades. Doctors tell patients who are at risk of developing stones to drink lots of water and avoid foods rich in oxalate, such as rhubarb, okra, spinach and almonds. They often recommend taking citrate (CA), in the form of potassium citrate, a supplement that can slow crystal growth, but some people are unable to tolerate the side effects.