High-Protein Diets May Cause Kidney Stones

GRANADA, SpainAlthough high-protein diets are commonly used for weight loss, new research published in Nutrición Hospitalaria reveals a diet high in protein may increase the risk of developing kidney stones and other renal diseases.

In an experiment conducted at the University of Granada, lead author Virginia A. Aparicio and his colleagues found high-protein diets can increase the long-term risk of developing kidney disease, and they may also have a negative effect on renal urinary and morphological markers. Scientists used lab rats to examine the effects of a high-protein diet on renal urinary, plasma and morphological parameters.

The researchers studied 20 Wistar rats, which were divided into two groups of 10. The first group was fed a high-protein diet of commercial hydrolysed protein supplements with a 45% protein level. The control group was fed a normal protein diet. The experiment lasted 12 weeks, which is the equivalent of 9 years in human terms.

The results showed that the rats on a high-protein diet lost up to 10% of their body weight over the 12 weeks with no improvement in their plasma lipid profile. Also, urinary citrate in these rats was 88% lower and urinary pH was 15% more acidic. In the animals fed a high-protein diet, kidney weight increased by 22%.

The results of this study stress the need to closely monitor anyone on a high-protein diet. The Dukan diet, and others like it, can have serious long-term adverse effects on health. Aparicio added that the negative effects of high-protein diets on the kidney also depend on the presence of other nutrients in the diet.

Eating large amounts of fruit and vegetables reduces the risk of kidney stones formingprobably due to their high potassium and magnesium content, which compensates for the acidity of the high-protein diet," Aparicio said.