Prevent kidney stones with natural fruit extract

Natural fruit extract can dissolve the most common component of human kidney stones- calcium oxalate crystals.

The findings of the study conducted by University of Houston could lead to the first advance in the treatment of calcium oxalate stones in 30 years.

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.

According to lead author Jeffrey Rimer, the findings are the result of a combination of experimental studies, computational studies and human studies.

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.

The project grew out of preliminary work done by collaborator John Asplin who suggested HCA as a possible treatment.

HCA is chemically similar to CA and is also available as a dietary supplement.

"HCA shows promise as a potential therapy to prevent kidney stones. HCA may be preferred as a therapy over CA (potassium citrate)," wrote the researchers.

The head-to-head studies of CA and HCA determined that while both compounds inhibit the growth of calcium oxalate crystals, HCA was more potent and displayed unique qualities that are advantageous for the development of new therapies.

While Rimer said the research established the groundwork to design an effective drug, questions remain as long-term safety, dosage and additional human trials are needed.

"But our initial findings are very promising. If it works in vivo, similar to our trials in the laboratory, HCA has the potential to reduce the incidence rate of people with chronic kidney stone disease," he said.

The study has been published in the online edition of Nature.