In the "Plant-Based" Era, Patients With Chronic Kidney Disease Should Focus on Eating Healthy

Adherence to a Healthy Plant-Based Diet and Cardiovascular-Kidney-Metabolic Risk Factors in Patients with Moderate to Advanced Chronic Kidney Disease

OBJECTIVE

The confluence of cardiovascular-kidney-metabolic (CKM) risk factors and chronic kidney disease (CKD) elevates the risk for adverse cardiovascular and kidney outcomes. Mounting evidence has emerged on the benefits of plant-based diets for CKD management. However, whether the benefits are mediated by improved CKM health are unclear. In addition, there remain concerns about the risk of malnutrition and hyperkalemia associated with plant-based diets. The objective of this study was to assess the relationship between adherence to healthy plant-based diets and CKM syndrome, nutritional status, and serum potassium levels in patients with nondialysis CKD stages 3-5.

METHOD

A total of 147 patients (median age 66 years) with CKD (median eGFR 23.1 mL/min/1.73 m2) were included. Responses to a food frequency questionnaire developed for the Asian population with CKD were used to calculate a healthy plant-based diet score (HPDS), which reflects higher consumption of plant foods and reduced intake of animal products and sugar. CKM risk factors included overweight/obesity, central obesity, high blood pressure, high triglycerides, and high blood glucose. Nutritional status was assessed using serum albumin and dietary energy and protein intake.

RESULTS

In logistic regression analyses, a higher HPDS was significantly associated with lower odds of all CKM risk factors and malnutrition. After adjusting for age, sex, comorbidities, lifestyle factors, and medications, a higher HPDS remained significantly linked to lower odds of overweight/obesity and central obesity, as well as higher odds of having a normal serum albumin level (≥ 3.8 g/dL), dietary protein intake (≥ 0.6 g/kg/day), and dietary energy intake (≥ 25 g/kg/day). No significant association was observed between HPDS and hyperkalemia.

CONCLUSIONS

In patients with moderate to advanced CKD, healthy plant-based diets were associated with a lower risk of CKM syndrome. Adherence to a healthy plant-based diet was more likely to achieve a better nutritional status and was not associated with risk of hyperkalemia.

Plant-Based Diet and Chronic Kidney Disease: A Systematic Review and Meta-Analysis

OBJECTIVE

We aimed to perform a systematic review and meta-analyses to evaluate the impact of plant-based diet (PBD) on chronic kidney disease (CKD).

METHODS

A systematic search of PubMed and Embase was conducted from inception to August 2023 to evaluate the association between adopting a PBD and the incidence, progression, and mortality of CKD. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using a random effects model. This meta-analysis was preregistered in the PROSPERO.

RESULTS

A total of 121,927 participants were included, aged between 18 and 74 years, and were followed up for a weighted average of 11.2 years. Adopting PBD is associated with a significantly reduced risk of developing CKD OR = 0.75, 95% CI (0.65-0.86), P < .0001] across 93,857 participants. Similar results were observed in subgroup analyses that examined higher quintiles/quartiles (Q2-Q5) and tertiles (T2-T3) of PBD versus Q1/T1, with overall effect measures of 0.92 (95% CI; 0.86-0.98) and 0.88 (95% CI; 0.82-0.93), respectively. When adjusting for CKD-related comorbidities in patients following PBD (adjusted models M1, M2, and M3), significant findings were also observed, with an overall OR of 0.86 (95% CI; 0.79-0.93).

CONCLUSION

Adopting PBD was significantly associated with 26% lower incidences of CKD. Higher intake of PBD showed a dose-dependent relationship with lower risk of CKD incidence and slower CKD progression. Unhealthy PBD may not confer renal protective effects compared to healthy PBD.

Association Between Potential Renal Acid Load and 10-Year Mortality in Patients on Hemodialysis

OBJECTIVES

Higher dietary acid load (DAL) has been linked to elevated incidence and progression of chronic kidney disease. However, the association between DAL and mortality in patients on maintenance hemodialysis (MHD) has not been evaluated.

METHODS

We retrospectively analyzed baseline laboratory data, self-administered diet history questionnaire results, and 10-year mortality rates in 44 patients (26 men, 67.9 ± 10.4 years) on MHD who participated in a randomized, double-blind, crossover pilot trial of rice endosperm protein supplementation, which was conducted in 2013. DAL was estimated from nutrition intake using potential renal acid load (PRAL), and patients were divided into tertiles using this score.

RESULTS

During the 10-year observation period, 19 patients (43%) died. A higher PRAL score was significantly associated with higher all-cause mortality. The multivariable-adjusted hazard ratio for all-cause mortality in the highest tertile of PRAL versus the lowest tertile was 3.88 (95% confidence interval [CI], 1.10-13.61). Multiple logistic regression analysis showed a significant association between higher PRAL and lower intake of green and yellow vegetables (odds ratio, 5.40; 95% CI, 1.37-21.26) and fruits (odds ratio, 4.76; 95% CI, 1.30-16.76).

CONCLUSIONS

Higher PRAL is positively associated with all-cause mortality, and these associations might be affected by a lower intake of fruits and vegetables in Japanese patients on MHD.

The Impact of a Western Diet High in Phosphate on the CKD-MBD in an Alport Syndrome Model

Background

Chronic kidney disease - mineral bone disorder (CKD-MBD) is a syndrome that begins early in CKD, contributes to CKD-associated mortality, and includes components of FGF23 elevation, αklotho deficiency, CKD-stimulated vascular disease, and renal osteodystrophy. Hyperphosphatemia, occurring in later stages of CKD, is also driven by mechanisms of CKD-MBD, and has been shown to stimulate vascular calcification. In a mouse model of Alport CKD that is resistant to vascular calcification, we examine the effects of a high-phosphate Western-type diet on the CKD-MBD, and test whether the diet promotes induction of vascular calcification.

Methods

An X-linked Col4a5 deficient murine homolog of Alport Syndrome (CKD) and wild type (WT) littermates were fed an animal protein 1.2% high phosphate diet or a standard vegetable protein diet. At disease progression equivalent to CKD stage 4-5, we examined kidney histology for fibrosis, blood for BUN (marker of CKD), and markers of CKD-MBD disease progression, kidney tissue for klotho production, and aorta histology and tissue mRNA and protein analysis for vascular calcification.

Results

The Western high Pi diet produced hyperphosphatemia in the CKD animals compared to WT and increased plasma PTH (1880 from 110 pg / ml), FGF23 c-term (670 from 120 pg / ml), and FGF23 intact (3780 from 280 pg / ml), and reduced kidney klotho mRNA and protein (57-67% reduction) (all p < 0.01). Referenced against the CKD animals fed vegetable-based diet, the Western high phosphate-fed CKD animals showed higher levels of plasma PTH and FGF23s. In the wild-type control mice with normal renal function, Western diet produced increased PTH, intact FGF23, and reduced renal klotho (all p <0.01). Vascular smooth muscle transdifferentiation and vascular calcification was not induced by Western high phosphate diet in this model of CKD.

Conclusions

Our results show that a Western-style high-phosphate diet advances elements of the CKD-MBD. Renal klotho, FGF23 and PTH are affected by diet even with normal kidney function, suggesting a need for early intervention in the management of phosphate homeostasis as a component of CKD therapy. Additionally, CKD, klotho, and FGF23 all are associated with early aging. Therefore, our findings suggest that a Western high Pi diet accelerates aging and would contribute to the systemic complications of CKD - cardiac disease, osteodystrophy, and vascular disease.