Plant-Dominant Low Protein Diet: A Potential Alternative Dietary Practice for Patients with Chronic Kidney Disease

Abstract

Dietary protein restriction has long been a cornerstone of nutritional therapy for patients with chronic kidney diseases (CKD). However, the recommended amount of dietary protein intake is different across guidelines. This is partly because previous randomized controlled trials have reported conflicting results regarding the efficacy of protein restriction in terms of kidney outcomes. Interestingly, a vegetarian, very low protein diet has been shown to reduce the risk of kidney failure among patients with advanced CKD, without increasing the incidence of hyperkalemia. This finding suggests that the source of protein may also influence the kidney outcomes. Furthermore, a plant-dominant low-protein diet (PLADO) has recently been proposed as an alternative dietary therapy for patients with CKD. There are several potential mechanisms by which plant-based diets would benefit patients with CKD. For example, plant-based diets may reduce the production of gut-derived uremic toxins by increasing the intake of fiber, and are useful for correcting metabolic acidosis and hyperphosphatemia. Plant proteins are less likely to induce glomerular hyperfiltration than animal proteins. Furthermore, plant-based diets increase magnesium intake, which may prevent vascular calcification. More evidence is needed to establish the efficacy, safety, and feasibility of PLADO as a new adjunct therapy in real-world patients with CKD.

Keywords: chronic kidney disease; low-protein diet; magnesium; plant-based diet.

Figure 1

Potential benefits of plant-based diet for patients with CKD. Plant-based diets increase fiber intake, which may improve gut dysbiosis and reduce the production of gut-derived uremic toxins. Plant phosphorus is less absorbable than animal phosphorus because it is bound to phytates, which are difficult for humans to digest. Thus, plant-based diets contribute to reducing the phosphorus burden. Alkali-rich plant foods reduce dietary acid load and correct metabolic acidosis. Plant proteins are less likely to induce glomerular hyperfiltration compared to animal proteins. Finally, plant-based diets increase magnesium intake, which may prevent vascular calcification. ↑: increase, ↓: decrease.

Figure 2

Serum magnesium levels modify the association between serum phosphate levels and cardiovascular death in hemodialysis patients. (A) High serum phosphate levels are associated with an increased risk of cardiovascular death in those with serum magnesium levels <2.7 mg/dL. However, this association is attenuated in those with serum magnesium levels 2.7–3.0 mg/dL (B) and 3.1 mg/dL or greater (C). The dashed lines represent 95% confidence intervals. Cited from Ref. [69]; Abbreviation: Mg, magnesium.