A flavonoid-rich diet is associated with a lower risk of chronic kidney disease: A prospective cohort study

Abstract

Background and aim: Mechanistic data suggests several flavonoids may improve kidney function, but no large-scale prospective cohort study has been conducted. As such, we performed a prospective population-based study on flavonoid intakes, chronic kidney disease (CKD) risk, and all-cause mortality among participants with CKD.

Methods: We examined associations between a Flavodiet score (FDS), individual flavonoid-rich foods and subclasses (based on ≥2 24-h dietary assessments) and a) CKD risk among 109,711 adults, and b) all-cause mortality among 3,287 participants with CKD at baseline, aged 40-69 years using multivariable Cox regression analyses. Additionally, we used mediation analysis to examine potential mechanisms of action.

Results: Over 10.5 y follow-up, 4,257 cases of incident CKD were identified. A higher FDS, characterized by a median of 6 servings of flavonoid-rich foods per day, was associated with a 16 % lower risk of CKD (HR (95%CI) _{Q4 vs Q1}, P trend = 0.84 (0.77, 0.92), <0.001), in part mediated by levels of triglycerides (2.8 %), high-density lipoprotein (5.9 %), glycated hemoglobin (2.2 %), Cystatin-C (16.6 %), and C-reactive protein (2.1 %). Additionally, we observed significant inverse associations between a range of flavonoid-rich foods (apples, oranges, berries, and red wine) and flavonoid subclasses (anthocyanins, proanthocyanidins, flavonols, flavanones, and flavones) and CKD risk. Among participants with prevalent CKD, a higher FDS (median of 6 servings per day) was associated with a 27 % lower risk of all-cause mortality compared to Q1, although the P for trend did not reach statistical significance (HR (95%CI) _{Q4 vs Q1,} P trend: 0.73 (0.54, 0.97), 0.10).

Conclusion: A flavonoid-rich diet consisting of a median of 6 servings per day of commonly consumed flavonoid-rich foods such as apples and berries, was associated with a lower risk of CKD, and a lower risk of all-cause mortality in individuals with CKD in middle-aged adults. Simple dietary change to increase intakes of these commonly consumed food and drink items may lower CKD risk, and improve CKD prognosis.

Keywords: All-cause mortality; Chronic kidney disease; Flavonoid-rich foods; Flavonoids; Inflammation; Lipid metabolism.