Plant-Based Proteins and Renal Protection in Acute Kidney Injury: Nutritional and Metabolic Perspectives

Acute kidney injury (AKI) is a frequent complication in critically ill patients and is associated with high morbidity, mortality, and an increased risk of progression to chronic kidney disease (CKD). In this context, nutritional management represents a key component of supportive therapy, as AKI is commonly characterized by hypercatabolism, negative nitrogen balance, and protein-energy wasting. Current nutritional strategies primarily focus on the quantity of protein intake required to compensate for catabolic losses, particularly in patients undergoing renal replacement therapy (RRT). However, growing evidence suggests that the quality and metabolic effects of dietary protein sources may also influence renal physiology and recovery. Plant-based proteins have recently gained attention as a potentially advantageous nutritional strategy in kidney disease. Compared with animal-derived proteins, plant-based proteins are associated with a lower dietary acid load, reduced production of gut-derived uremic toxins, and beneficial effects on the intestinal microbiota. In addition, their amino acid profile may modulate oxidative stress, inflammatory pathways, and renal hemodynamics. These characteristics may contribute to a more favorable metabolic environment in patients with AKI, potentially supporting renal recovery and reducing the risk of AKI-to-CKD transition. This review examines the pathophysiological mechanisms linking protein metabolism, renal injury, and nutritional support in AKI. Particular attention is given to the role of plant-based proteins, their amino acid composition, and their potential nephroprotective effects. Understanding the interaction between dietary protein sources, metabolic pathways, and the gut–kidney axis may help guide future nutritional strategies aimed at improving outcomes in critically ill patients with AKI.