Optimal Protein Intake in Pre-Dialysis Chronic Kidney Disease Patients with Sarcopenia: An Overview

Abstract

Multi-factors, such as anorexia, activation of renin-angiotensin system, inflammation, and metabolic acidosis, contribute to malnutrition in chronic kidney disease (CKD) patients. Most of these factors, contributing to the progression of malnutrition, worsen as CKD progresses. Protein restriction, used as a treatment for CKD, can reduce the risk of CKD progression, but may worsen the sarcopenia, a syndrome characterized by a progressive and systemic loss of muscle mass and strength. The concomitant rate of sarcopenia is higher in CKD patients than in the general population. Sarcopenia is also associated with mortality risk in CKD patients. Thus, it is important to determine whether protein restriction should be continued or loosened in CKD patients with sarcopenia. We may prioritize protein restriction in CKD patients with a high risk of end-stage kidney disease (ESKD), classified to stage G4 to G5, but may loosen protein restriction in ESKD-low risk CKD stage G3 patients with proteinuria <0.5 g/day, and rate of eGFR decline <3.0 mL/min/1.73 m2/year. However, the effect of increasing protein intake alone without exercise therapy may be limited in CKD patients with sarcopenia. The combination of exercise therapy and increased protein intake is effective in improving muscle mass and strength in CKD patients with sarcopenia. In the case of loosening protein restriction, it is safe to avoid protein intake of more than 1.5 g/kgBW/day. In CKD patients with high risk in ESKD, 0.8 g/kgBW/day may be a critical point of protein intake.

Nutrition in Patients with Type 2 Diabetes: Present Knowledge and Remaining Challenges

“…However, protein restriction may worsen sarcopenia and should be limited as long as possible. According to the National Kidney Foundation/Kidney Disease Outcomes Quality Initiative (NKF-KDOQI) Guidelines, protein intake must actually be increased up to 1.2 g/kg body in patients undergoing maintenance dialysis due to important additional amino acid losses occurring in dialysate [ 200 , 201 ].…”

Perspectives on Sarcopenia and Protein Intake in Aged and Diabetic Patients

“…This mechanism involves the presence or absence of sarcopenia. Based on the above situation, the Japanese Society of Nephrology published "Recommendations for Diet for Conservative CKD with Sarcopenia Frail" in 2019 [12]. Among them, protein intake should be set flexibly by examining whether to emphasize the prevention of ESRD or the risk of death [13].…”

Extension of Healthy Life Span of Dialysis Patients in the Era of a 100-Year Life

“…With both the elongation of hemodialysis (HD) duration resulting from the sophistication of HD technology and the increasing age at the time of HD initiation due to the aging society of Japan, the mean age of prevalent HD patients is increasing at an accelerating rate [ 1 ]. Along with the aging of HD patients, presymptomatic conditions such as malnutrition, frailty, sarcopenia, and inflammation have been focused on as important states to help to improve the condition of patients, both those living independently and those requiring physical support or nursing care [ 1 , 2 ], as in the general elderly population. In addition, it should be emphasized that such presymptomatic conditions can often act as a trigger, causing critical events, such as cardiovascular disease (CVD), falls, and fragile fractures, which significantly impair quality of life (QOL) [ 1 ].…”

“…Based on these findings, sufficient calorie/protein intake is essential in undernourished elderly HD patients [ 6 ]. Traditionally, protein restriction diet therapy has been recommended to protect against the decline in renal function in pre-dialysis chronic kidney disease (CKD) patients [ 2 ]. However, inadequate protein intake may exacerbate malnutrition to induce sarcopenia and emaciation in such patients.…”

“…However, inadequate protein intake may exacerbate malnutrition to induce sarcopenia and emaciation in such patients. Thus, flexible responses are considered regarding whether protein restriction should be continued or loosened in pre-dialysis CKD patients [ 2 ]. With an increase in protein intake, hyperphosphatemia is another key factor to be avoided in CKD/HD patients since phosphate overload leads to secondary hyperparathyroidism and vascular calcification, causing fractures and CVD events, respectively [ 7 ].…”