Effects of Plant-Based Protein Consumption on Kidney Function and Mineral Bone Disorder Outcomes in Adults With Stage 3-5 Chronic Kidney Disease: A Systematic Review

Abstract

Plant-based protein is of growing interest for dietary management of chronic kidney disease (CKD) and is hypothesized to preserve kidney function and reduce CKD-mineral bone disorder (MBD) complications among other benefits. This systematic review aimed to summarize the available clinical trial evidence for the effect of plant-based protein on kidney function and CKD-MBD outcomes in adults with stage 3-5 CKD not on dialysis. Searches of Medline, Embase, Agricola, CAB abstracts, Web of Science, Scopus, and hand searching were performed. Clinical trials with ≥8 participants ≥18 years of age with an eGFR <60 mL/min/1.72m2 but not on dialysis were included. Additionally, only clinical trials with ≥1-week interventions with ≥50% dietary protein from plant-based sources and reported at least one outcome for both kidney function and CKD-MBD outcomes were included. Of 10,962 identified abstracts, 32 met inclusion criteria and were assessed for risk of bias. Results for kidney function and CKD-MBD outcomes were heterogenous, with most studies having suboptimal methodological quality. In most of the studies (27/32), protein source was altered only secondarily to low protein diet interventions. Thus, data synthesis and interpretation were focused on a subset of five studies that investigated a change in protein source only (i.e., animal vs plant). Of this subset, four studies reported no change in kidney function while one study reported a decrease. Three studies reported no change in serum phosphorus and one study reported lower serum phosphorus following a vegetarian diet. Further, limited data and inconclusive results were observed for phosphaturic hormones, PTH and FGF-23. Current clinical trial evidence on plant-based protein interventions for preserving kidney function and preventing CKD-MBD is limited to inform clinical guidelines at this time. This systematic review emphasizes the on-going need to research the effects of plant-based protein on kidney function and CKD-MBD outcomes.