Protein intake and renal function in older patients

Abstract

Purpose of review Chronic kidney disease (CKD) is highly prevalent in elderly patients. There is growing recognition of the importance of attention to dietary protein intake (DPI) in this population given their predisposition to agerelated changes in kidney function and coexisting comorbidities (i.e., hypertension). We reviewed the impact of DPI on kidney health and survival and the role of dietary protein management in older CKD patients. Recent findingsWhile kidney function parameters including glomerular filtration rate (GFR) and renal plasma flow are slightly lower in elderly patients irrespective of CKD status, the kidneys' ability to compensate for increased DPI by augmentation of GFR is preserved until 80 years of age or less. However, long-term consumption of high DPI in individuals of older age and/or with CKD may contribute to kidney function deterioration over time. Prescription of a plant-dominant low-protein diet of 0.6-0.8 g/kg/day with more than 50% from plant sources or very low protein diets less than 0.45 g/kg/day supplemented with essential amino acids or their keto-analogues may be effective in preserving kidney function in older patients and their younger counterparts, while also monitoring for development of protein-energy wasting (PEW).

Urinary metabolite profiling and risk of progression of diabetic nephropathy in 2670 individuals with type 1 diabetes

“…We do not have data on diet, but secretion for most amino acids is not strongly influenced by protein intake in healthy individuals [ 23 ]. However, high protein intake in prevalent CKD may further kidney function decline [ 24 ]. Reduced tubular reabsorption may play an important role.…”

Personalized nutritional management in the transition from non-dialysis dependent chronic kidney disease to dialysis

“…Given various metabolic and nutritional changes that develop with declining kidney function, including 1) the accumulation of uremic toxins, such as catabolic by-products of protein metabolism and inflammatory cytokines, 2) reduced appetite and food intake, and 3) increased muscle catabolism in the setting of CKD-related metabolic acidosis and insulin resistance, patients with advanced CKD are at heightened risk of developing protein energy wasting [8]. Moreover, elderly CKD patients are at even higher risk for developing protein energy wasting due to age-related changes in body composition over time, namely increased body fat and decreased lean body mass, as well as the above CKD-associated metabolic and nutritional derangements [9].…”

“…Another randomized controlled trial has shown that a ketoacid analog supplemented with VLPD (dietary protein intake of 0.3 g/kg/day) mitigated kidney function decline and reduced the number of patients requiring renal replacement therapy [22]. Emerging data also demonstrate the benefits of LPDs in kidney disease patients of older age, who comprise a large proportion of the CKD population [9]. Indeed, a growing body of literature has shown that LPDs have kidney protective effects in both older and younger patients with CKD [23].…”

Pflanzliche Ernährung und ausreichende Proteinzufuhr für ein gesundes Altern

“…Hinsichtlich der Nierenfunktion lässt sich ebenfalls kein negativer Effekt einer erhöhten Proteinzufuhr im Alter abbilden. Im Gegenteil lässt eine rezente Untersuchung vermuten, dass selbst bei einer bereits bestehenden Nierenfunktionsbeeinträchtigung nicht die erhöhte Proteinzufuhr per se, sondern vielmehr eine reduzierte Zufuhr und das Vorliegen einer Protein-Energie-Malnutrition prädiktiv für einen negativen Nierenfunktionsverlauf sind [14]. Allerdings könnte sich die Erhöhung des pflanzlichen Proteinanteils eventuell günstig auf die Nierenfunktion und das renale Überleben auswirken [14].…”