Abstract
Background/Objectives: Increasing evidence indicates that a vegetarian diet may provide renal protection and improve metabolic health in patients with chronic kidney disease (CKD). However, transitioning from an omnivorous to a vegetarian diet can be challenging. A more practical alternative could be to increase the consumption of plant protein. In this cross-sectional study, we investigated the association between increased plant protein intake and adherence to a low-protein diet (LPD) and the effect on biochemical parameters, body composition, and muscle strength in patients with non-dialysis CKD stages 3-5. Methods: The daily dietary intake of 377 patients, aged 68.5 ± 12.1 years, was evaluated using a quantitative food frequency questionnaire. Plant protein intake percentage was calculated as (daily plant protein intake/total protein intake) × 100%, and the potential renal acid load (PRAL) was estimated. A LPD was defined as a diet with a daily protein intake of <0.8 g/kg of body weight. Anthropometric measurements, body composition, and handgrip strength were assessed in a subgroup comprising 260 patients. The lean tissue index (LTI) and fat tissue index (FTI) were calculated by dividing lean mass and fat mass (kg) by the height in m(2), respectively. Results: Of the included 377 patients, 69.5% adhered to the LPD. Further, a 10% increase in plant protein intake was associated with a 20% increase in the likelihood of LPD adherence (OR, 1.20, 95% CI, 1.06 to 1.37), lower PRAL (β = -1.10 per 10% increase, 95% CI, -1.63 to -0.57), and higher serum bicarbonate levels (β = 0.24, 95% CI, 0.02 to 0.45). Analysis of the 260-patient subgroup revealed that a 10% increase in plant protein intake was associated with lower body mass index (β = -0.82, 95% CI, -1.05 to -0.59), FTI (β = -0.71, 95% CI, -1.01 to -0.40), waist circumference (β = -2.11, 95% CI, -2.80 to -1.41), hip circumference (β = -1.25, 95% CI, -1.75 to -0.75), waist-to-hip ratio (β = -0.91, 95% CI, -1.44 to -0.38), and waist-to-height ratio (β = -1.25, 95% CI, -1.71 to -0.80). There was no significant association between increased plant protein intake and LTI and handgrip strength. Conclusions: Increased intake of plant protein can reduce dietary acid load, alleviate metabolic acidosis, and potentially improve adiposity parameters without compromising lean mass and handgrip strength.