Polyphenolic antioxidants derived from plant foods may reduce oxidative stress and frailty, but the effect of the polyphenol subclass of dietary flavonoids and their subclasses on frailty is uncertain.
To determine the association between dietary flavonoids, their subclasses, quercetin (a specific flavonol), and frailty onset in adults.
This prospective cohort study included individuals from the Framingham Heart Study with no frailty at baseline. Intake of total flavonoids, subclasses of flavonoids (flavonols, flavan-3-ols, flavonones, flavones, anthocyanins, and polymeric flavonoids), and quercetin were estimated via semi-quantitative FFQ along with frailty (Fried phenotype), and covariates at baseline (1998–2001). Frailty was re-evaluated in 2011–2014. Logistic regression estimated OR and 95% CIs for each flavonoid variable and frailty onset.
Mean age was 58.4 y (SD ± 8.3, n = 1701; 55.5% women). The mean total flavonoid intake was 309 mg/d (SD ± 266). After 12.4 (SD ± 0.8) y, 224 (13.2%) individuals developed frailty. Although total flavonoid intake was not statistically associated with frailty onset (adjusted OR: 1.00; 95% CI: 0.99–1.01), each 10 mg/d of higher flavonol intake was linked with 20% lower odds of frailty onset (OR: 0.80; 95% CI: 0.67–0.96). Other subclasses showed no association (P values range: 0.12–0.99), but every 10 mg/d of higher quercetin intake was associated with 35% lower odds of frailty onset (OR: 0.65; 95% CI: 0.48–0.88).
Although no association was observed between total flavonoid intake and frailty onset in adults, a higher intake of flavonols was associated with lower odds of frailty onset, with a particularly strong association for quercetin. This hypothesis-generating study highlights the importance of assessing specific subclasses of flavonoids and the potential of dietary flavonols and quercetin as a strategy to prevent the development of frailty.