The impact of high-protein diets on renal function: A comprehensive review

Introduction and purpose: Protein is one of the key macronutrients in the diet, playing an irreplaceable role in tissue construction and repair, as well as enzyme and hormone production. While it is widely recognised that a high-protein diet can be harmful to those with pre-existing kidney issues , there is limited evidence to suggest that high protein consumption poses a risk to healthy individuals. High-protein diets, defined as those in which protein intake exceeds standard recommendations (typically >1.2-2.2 g protein per kilogram of body weight per day), are frequently employed in medical and sporting contexts. The present article aims to investigate the effects of a high-protein diet on renal filtration function. Materials and methods: To write this article, data bases such as PubMed and Google Scholar were searched using the following terms: high protein diet, protein intake, renal function, renal failure ,chronic kidney disease, nutrition, glomerular filtration rate, GFR Description of the state of knowledge: A high-protein diet constitutes a significant component in the therapeutic management of various conditions, including, but not limited to, chronic illness, cachexia (particularly in cancer), and the aftermath of orthopaedic and surgical interventions, as well as extensive burns. Notably, high protein intake is frequently employed by individuals of sound health to achieve weight reduction (through fat loss), enhance muscle mass, prolong satiety, and regulate appetite. The kidneys are responsible for the removal of excess protein from the organism, a process that involves the filtration of urea and other nitrogenous products from the blood and their subsequent excretion in the urine. Summary: A review of studies demonstrated that short-term (up to several months) high-protein diets induced glomerular hyperfiltration, while long-term studies revealed decreased renal filtration function, particularly in individuals with cardiovascular disease and diabetes mellitus. However, there is an absence of compelling evidence associating increased protein intake with renal damage in healthy individuals. The necessity for large, long-term randomised trials in this population is underscored. For individuals with chronic kidney disease (CKD), studies have indicated that a high-protein diet may accelerate the deterioration of renal function, leading to an increase in creatinine levels and other indicators of kidney damage. Excessive protein supply may further increase glomerular filtration rate (GFR) burden, which may lead to faster progression of kidney disease.