Researchers suggest DASH-style diet reduces kidney stone formation

Certain key ingredients of a diet designed to prevent high blood pressure can ward off kidney stones, according to a study appearing in an upcoming issue of the Clinical Journal of the American Society Nephrology (CJASN). The results suggest how low-fat dairy products and/or plants may have potent kidney stone-fighting properties.

The Dietary Approaches to Stop Hypertension (DASH) diet—which is high in fruits, vegetables, nuts and legumes, dairy products, and whole grains and is low in sweetened beverages and red and processed meats—effectively lowers blood pressure. Research by Eric Taylor, MD (Brigham and Women's Hospital, Harvard Medical School, and Maine Medical Center) and his colleagues also now suggests that a DASH-style diet reduces one's risk of developing kidney stones.

The investigators studied 24-hour urine samples of 3426 individuals with and without a history of kidney stones in the Health Professionals Follow-up Study (HPFS) and the Nurses' Health Studies (NHS) I and II. The study participants were part of a previous, larger study where Dr. Taylor reported that a DASH-style diet was associated with a reduced risk of kidney stone formation. HPFS and NHS I and II are large studies of the lifestyle practices and health of both male and female health care workers.

Individuals who followed a DASH-style diet excreted more urine than individuals who did not follow the diet, despite similar fluid intake. The researchers speculate that higher urinary volumes were, at least partly, a result of the higher food water content in a DASH-style diet. Also, the urine of DASH consumers contained a higher concentration of citrate, an important inhibitor of calcium stones, than the urine of others in the analysis. The study also indicated that there may be other important, and perhaps as of yet unidentified, kidney stone inhibitors in dairy products and/or plants.

Dr. Taylor's data suggest that a DASH-style diet could be important for keeping stones from reappearing in people who suffer from them. "We believe our results provide a strong rationale for a randomized trial examining the effect of a DASH-style diet on kidney stone recurrence," the authors wrote.