Navigating between the Scylla and Charybdis of prescribing dietary protein for chronic kidney diseases.

A fundamental clinical problem in treating patients with chronic kidney disease (CKD) is designing their diets: an excess of protein leads to the accumulation of uremic toxins, whereas a diet insufficient in protein could lead to loss of lean body mass. The benefits of dietary protein restriction include reducing the accumulation of metabolic waste products that can suppress appetite and stimulate muscle protein wasting. There also is a potential for slowing the loss of kidney function. Unfortunately, advanced CKD is strongly associated with a protein wasting syndrome that is directly correlated with morbidity and mortality. Fortunately, the mechanisms underlying negative responses to an excess of dietary protein, including the causes of the wasting syndrome, are beginning to be understood. We have examined how dietary protein influences the mechanisms causing protein wasting, and we propose a framework for approaching the variable dietary protein requirements in patients with CKD or end-stage kidney disease.