Do low-carb diets damage the kidneys?

Low-carbohydrate, high-protein diets—like the Atkins diet—have been popular among dieters for years. For just as long, experts have worried that such diets might be harmful to the kidneys. A study appearing in an upcoming issue of the Clinical Journal of the American Society of Nephrology (CJASN) looks into these safety concerns.

Allon Friedman, MD, (Indiana University School of Medicine) and his colleagues compared the effects of a low-carbohydrate, high-protein diet versus a standard low-fat diet on a variety of kidney-related measures in 307 obese individuals without kidney disease over a two year period.

The researchers found that a low-carbohydrate high-protein weight loss diet did not cause noticeably harmful effects to patients' kidney function or their fluid and electrolyte balance compared with a low-fat diet. "These results are relevant to the millions of healthy obese adults who use dieting as a weight loss strategy," said Dr. Friedman.

The authors noted that further follow-up is needed to determine even longer-term effects of the diet on the kidneys. Additional studies should also evaluate the effects of the diet in different types of individuals, such as those with chronic kidney disease, diabetes, or hypertension, and those at increased risk of developing kidney stones.