A high-protein diet, often recommended as a way to lose weight and stay healthy, appears to be harmful to the kidneys in individuals with apparently normal kidney function, two separate new studies indicate. The two studies, from the Netherlands and Korea, were published online in Nephrology dialysis Transplantation. Many previous studies have shown that a high-protein diet may harm kidney function, and this is why nephrologists recommend patients with known early stage chronic kidney disease (CKD) stick to a low-protein diet. But people who have mild CKD of which they are unaware or those at high risk may follow the trend of eating a protein-rich diet because they believe it is healthy, say Kamyar Kalantar-Zadeh, MD, PhD, and colleagues in an accompanying editorial. "The high-protein culture has emerged as the preferred, healthy, and safe way of eating at the dawn of the 21st century," they write. Dietary regimens such as the Atkins, Zone, South Beach, and Ketogenic diets have emerged "in which daily protein intake increased to 20% to 25% or more of the total daily energy intake. We are being told that getting plenty of protein is the revival of our hunter–gatherer ancestral spirit and it will help maintain our lean muscle and reduce fat mass," the editorialists note. But given these two new studies, "and other data, it is time to unleash the taboo and make it loud and clear that a high-protein diet is not as safe as claimed, as it may compromise kidney health and result in a more rapid kidney function decline in individuals or populations at high risk of CKD," they underscore. "It is prudent to avoid recommending high-protein intake for weight loss in obese or diabetic patients, or those with prior cardiovascular events, or a solitary kidney if kidney health cannot be adequately protected," they summarize. "It is essential that people know there is another side to high-protein diets and that incipient kidney disease should always be excluded before one changes one's eating habits and adopts a high-protein diet," added the senior author of the editorial, Denis Fouque, MD, PhD, of Centre Hospitalier Lyon-Sud, France, in a press release issued by the European Renal Association-European dialysis and Transplant Association (ERA-EDTA). Dutch Study: Protein Intake, CKD Risk Highest in Those With Diabetes In the Dutch study, Kevin Esmeijer, MD, of Leiden University Medical Center, the Netherlands, and colleagues collected dietary data using a food frequency questionnaire from 4837 patients 60-80 years of age with a history of myocardial infarction involved in the Alpha Omega Trial. "At baseline and 41 months follow-up, serum cystatin C (cysC) and serum creatinine were measured from stored blood samples," the investigators explain. The mean age of the cohort was 69 years and mean estimated glomerular filtration rate (eGFR) was 82 mL/min/1.73m2. As the authors point out, compared with the general population, patients with a history of myocardial infarction have double the rate of annual decline in kidney function and thus are at higher risk for CKD. Source
