Adherence to dietary recommendations and chronic kidney disease : insights into disease onset and progression

Background: CKD is becoming a major global health concern, marked by a gradual, permanent decline in kidney function, constrained treatment possibilities, and rising healthcare expenses. Dietary modifications play an important role in managing risk factors for CKD incidence and in slowing its progression, and these adjustments should be based on dietary guidelines. However, current guidelines predominantly rely on Western-based evidence, leaving critical gaps in protein types, dietary patterns, and cultural adaptability. Given the significant differences in food structure and dietary habits between China and many Western countries, it is essential to explore these aspects within the Chinese population.

Aim: The thesis aims to evaluate diet quality and adherence to the Chinese 2017 Dietary Guide for Chronic Kidney Disease Patients (WS/T 557-2017) in Chinese patients and to provide evidence on how adherence to recommendations from dietary guidelines influences the onset and progression of CKD.

Study I is a cross-sectional study to investigates the dietary quality and adherence to Chinese CKD-specific nutritional guidelines among 261 non- dialysis-dependent CKD (NDD-CKD) stages G3-G5 patients. Findings revealed that a significant number of patients exhibited poor adherence to dietary recommendations, particularly regarding protein, energy, fiber, and sodium intake. The overall dietary quality in these patients was moderate, though characterized by notably reduced consumption of whole grains, dairy products, and soybeans.

Study II evaluates the association between plant protein ratio and CKD progression in 259 CKD G3-5 patients. After a median follow-up period of 2.3 years, our analysis identified a U-shaped relationship between plant protein ratio and CKD progression, with a turning point observed at 47%. Among patients with a plant protein ratio below 47%, each 5% increase in the ratio was associated with a 33% reduction in the risk of disease progression.

Study III included 197 participants with CKD stages 3-4 to evaluate the association between adherence to three healthy dietary indices and CKD progression and kidney function decline. Our key findings demonstrate that higher adherence to the Chinese Healthy Eating Index (CHEI) was associated with reduced CKD progression. Greater adherence to the CHEI and the healthy Plant-based Dietary Index (hPDI) was linked to a slower annual decline in eGFR in a dose-response manner. The Diet Quality Index-International (DQI-I) was not significantly associated with CKD progression or decline in eGFR.

Study IV was a systematic review and meta-analysis. Evidence from four cohorts comprising 219,132 participants was synthesized to examine the association between ultra-processed food (UPF) consumption and the risk of developing CKD. The results indicated that higher UPF intake was associated with an increased risk of incident CKD.

Conclusion: Patients with CKD stages 3-5 in our clinic exhibit that some nutrients that deviates from national recommendations and moderate diet quality. A U-shape association between plant protein ratio and CKD progression was observed in patients with CKD stages 3-5, with an inflection point at 47%. Among patients with CKD stages 3-4, greater adherence to the Chinese Healthy Eating Index (CHEI) was associated with a lower risk of CKD progression and a slower decline in kidney function. In the general population, higher consumption of UPFs was linked to an increased risk of developing CKD.

List of scientific papers

I. Ouyang W, Xiao B, Chen H, Fu L, Tang F, Marrone G, Liu X, Wu Y and Carrero JJ. Dietary quality and adherence to dietary recommendations in Chinese patients with chronic kidney disease. Front Nutr. 2025;12:1547181. https://doi.org/10.3389/fnut.2025.1547181

II. Ouyang W, Chen H, Fu L, Tang F, Carrero JJ, Marrone G, Stålsby Lundborg C, Eriksen J, Liu X and Wu Y. U-shape Association Between Dietary Plant Protein Ratio and Chronic Kidney Disease Progression. [Manuscript]

III. Ouyang W, Fu L, Tang F, Marrone G, Chen H, Wen Z, Wu Y and Liu X. Adherence to Four Dietary Indices and Chronic Kidney Disease Progression and Kidney Function Decline: Findings from the SMP-CKD Study. [Manuscript]

IV. Xiao B, Huang J, Chen L, Lin Y, Luo J, Chen H, FU L, Tang F, Ouyang W, Wu Y. Ultra-processed food consumption and the risk of incident chronic kidney disease: a systematic review and meta-analysis of cohort studies. Ren Fail. 2024;46(1):2306224. https://doi.org/10.1080/0886022X.2024.2306224