Long-term dietary flavonoid intake and subjective cognitive decline in US men and women

Objective: To prospectively examine the associations between long-term
dietary flavonoids and subjective cognitive decline (SCD). Methods: We
followed 49,493 women from the Nurses’ Health Study (NHS) (1984-2006) and
27,842 men from the Health Professionals Follow-up Study (HPFS)
(1986-2002). Poisson regression was used to evaluate the associations
between dietary flavonoids (flavonols, flavones, flavanones, flavan-3-ols,
anthocyanins, polymeric flavonoids, and proanthocyanidins) and subsequent
SCD. For the NHS, long-term average dietary intake was calculated from
seven repeated food frequency questionnaires (SFFQs), and SCD was assessed
in 2012 and 2014. For the HPFS, average dietary intake was calculated from
five repeated SFFQs, and SCD assessed in 2008 and 2012. Results: Higher
intake of total flavonoids was associated with lower odds of SCD after
adjusting for age, total energy intake, major non-dietary factors, and
specific dietary factors. Comparing the highest versus the lowest
quintiles of total flavonoid intake, the pooled multivariable-adjusted
odds ratios (ORs) (95% CIs) of 3-unit increments in SCD was 0.81
(0.76, 0.89). In the pooled results, the strongest associations were
observed for flavones (OR=0.62 [0.57, 0.68]), flavanones (0.64 [0.58,
0.68)]), and anthocyanins (0.76 [0.72, 0.84]) (p trend <0.0001 for
all groups). The dose-response curve was steepest for flavones, followed
by anthocyanins. Many flavonoid-rich foods, such as strawberries, oranges,
grapefruits, citrus juices, apples/pears, celery, peppers, and bananas,
were significantly associated with lower odds of SCD. Conclusion: Our
findings support a benefit of higher flavonoid intakes for maintaining
cognitive function in US men and women.