Editors' Note: Long-term Dietary Flavonoid Intake and Subjective Cognitive Decline in US Men and Women

Abstract

Using registry data from the prospective Nurse's Health Study and the Health Professional's Follow-up Study, Dr. Yeh et al. evaluated cognitive outcomes after dietary flavonoid consumption. As naturally occurring antioxidants with the potential for reducing oxidative stress in the nervous system, flavonoids may be nutrients that can reduce the cognitive decline that has been tied to oxidative stress. Given the large sample size of more than 75,000 patients with follow-up exceeding 20 years, Yeh et al. used Poisson regression to evaluate the relationship between total flavonoid use (and flavonoid subtypes) with subjective, patient-reported, cognitive decline (SCD). The multivariable model accounted for other dietary components and relevant medical and social history. Compared with the lowest quintile of total flavonoid intake, subjects reporting the highest quintile of flavonoid intake were at 19% lower odds of SCD after adjustment for covariates—with flavones (found in oranges, peppers, celery) being the most strongly tied to better cognitive outcomes. In response to the research article, Dr. Abe cautions readers regarding excess intake of flavonoids, citing literature that may have implicated higher flavonoid intake with cerebrovascular disease, cancer, and even depression. On more careful review of these studies, however, it seems higher flavonoid intake is actually protective against these conditions. Using registry data from the prospective Nurse's Health Study and the Health Professional's Follow-up Study, Dr. Yeh et al. evaluated cognitive outcomes after dietary flavonoid consumption. As naturally occurring antioxidants with the potential for reducing oxidative stress in the nervous system, flavonoids may be nutrients that can reduce the cognitive decline that has been tied to oxidative stress. Given the large sample size of more than 75,000 patients with follow-up exceeding 20 years, Yeh et al. used Poisson regression to evaluate the relationship between total flavonoid use (and flavonoid subtypes) with subjective, patient-reported, cognitive decline (SCD). The multivariable model accounted for other dietary components and relevant medical and social history. Compared with the lowest quintile of total flavonoid intake, subjects reporting the highest quintile of flavonoid intake were at 19% lower odds of SCD after adjustment for covariates—with flavones (found in oranges, peppers, celery) being the most strongly tied to better cognitive outcomes. In response to the research article, Dr. Abe cautions readers regarding excess intake of flavonoids, citing literature that may have implicated higher flavonoid intake with cerebrovascular disease, cancer, and even depression. On more careful review of these studies, however, it seems higher flavonoid intake is actually protective against these conditions.