Low-BP diet may offer advantages in cutting stone risk

March 3, 2014

A diet typically used to lower blood pressure may reduce the risk of kidney stone development, according to a small, recently published study.

A diet typically used to lower blood pressure may reduce the risk of kidney stone development, according to a small, recently published study.

Study authors, reporting their findings in the American Journal of Kidney Diseases (2014; 63:456-63), found that compared with following a low-oxalate diet-the frequently prescribed diet for kidney stone prevention and treatment-a Dietary Approaches to Stop Hypertension (DASH)-style diet may be more effective at reducing urinary risk markers for calcium oxalate kidney stone formation.

The DASH diet is high in fruits, vegetables, legumes, and nuts; moderate in low-fat dairy products; and low in animal proteins, refined grains, and sweets.

Researchers led by Nazanin Noori, MD, PhD, at the Hospital for Sick Children in Toronto examined the dietary interventions of 41 recurrent stone formers with hyperoxaluria over the course of 8 weeks. The intervention group followed a DASH-style diet, while the control group was prescribed a low-oxalate diet.

The authors noted a trend for increased urinary oxalate excretion in patients on the DASH diet versus the low-oxalate diet (point estimate of difference, 9.0 mg/d; 95% confidence interval [CI]: 21.1-19.1 mg/d; p=.08), but a trend for calcium oxalate supersaturation to decrease in the DASH versus the low-oxalate group (point estimate of difference, 21.24; 95% CI: 22.80-0.32; p=.08). Magnesium and citrate excretion and urine pH increased in the DASH versus the low-oxalate group (point estimates of difference of 17.7 mg/d [95% CI: 2.5-32.9 mg/d; p<.05], 221.5 mg/d [95% CI: 117.4-325.5 mg/d; p<.01], and 0.6 [95% CI: 0.3-0.9; p<.01], respectively), the authors reported.

While the results did not reach statistical significance, “The DASH diet might be an effective alternative to the low-oxalate diet in reducing calcium oxalate supersaturation and should be studied more,” Dr. Noori and colleagues wrote.

The data may also suggest a more rational dietary approach to nephrolithiasis prevention.

"Most people do not eat single, isolated nutrients, such as oxalate, but rather meals consisting of a variety of foods. So a practical diet plan for kidney stone prevention should be based on the cumulative effects of foods and the impact overall dietary patterns have on risk for stone formation rather than single nutrients,” Dr. Noori said.

 

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