Low-Protein Diets, Malnutrition, and Bone Metabolism in Chronic Kidney Disease

Chronic kidney disease (CKD) has a high prevalence worldwide, with increasing incidence in low- and middle-income countries, and is associated with high morbidity and mortality, particularly from cardiovascular disease. Protein-restricted diets are one of the most widely used non-pharmacological approaches to slow the progression of CKD and prevent associated metabolic abnormalities. However, some concerns have been raised about the long-term safety of these diets, particularly with regard to patients' nutritional status and bone and mineral disorders. Therefore, the aim of this article is to review the most recent scientific evidence on the relevance of using protein-restricted diets (with or without keto-analogue supplementation) and, in particular, their relationships with malnutrition and mineral and bone disorders in people with CKD without kidney replacement therapies. Although protein-restricted diets, especially when supplemented with keto-analogues and highly personalized and monitored, do not appear to be associated with malnutrition, research on their effects on bone and mineral disorders is scarce, deserving further investigation.