Higher dietary intake of total flavonols and individual flavonol constituents was linked with slower cognitive and memory decline in older adults, a longitudinal study showed.
Total flavonol intake was associated with lower decline in global cognition (β=0.004, 95% CI 0.001-0.006), according to Thomas Monroe Holland, MD, MS, of Rush University Medical Center in Chicago, and co-authors.
Slower declines in episodic, semantic, and working memory also were tied to overall flavonol intake. Associations were independent of cardiovascular conditions and lifestyle factors, the researchers reported in Neurology.
The findings suggest specific diet choices may lead to a slower rate of cognitive decline, Holland observed. “Something as simple as eating more fruits and vegetables and drinking more tea is an easy way for people to take an active role in maintaining their brain health,” he said in a statement.
Flavonols are a type of flavonoid, a group of phytochemicals found in plant pigments. Earlier research has shown that high flavonol intake was tied to lower risk of Alzheimer’s dementia.
The mechanisms behind these relationships aren’t fully understood. The anti-inflammatory features of flavonols may decrease the amplitude or duration of neuroinflammation, Holland and co-authors suggested. In addition, the antioxidant characteristics of flavanols may prevent or reduce oxidative stress from reactive oxygen species and free radicals, they noted.
In this study, Holland and colleagues evaluated 961 people with no dementia at baseline who participated in the Rush Memory and Aging Project, an ongoing community-based, prospective cohort. Participants were followed for 6.9 years.
The sample was predominantly female (75%), white (98%), and had an average educational level of 15 years and a mean baseline age of about 81. Overall, 22% carried at least one APOE4 allele and 42% reported a history of smoking.
The researchers assessed diet using a validated semi-quantitative food frequency questionnaire and measured cognitive performance annually with a battery of 19 standardized tests. They adjusted findings for age, sex, education, APOE4, late-life cognitive activity, physical activity, and smoking.
The study looked at both total flavonol intake and intake of four constituents — kaempferol, quercetin, myricetin, and isorhamnetin. Kale, beans, tea, spinach, and broccoli were top food contributors for kaempferol in the study. Tomatoes, kale, apples, and tea were main contributors for quercetin; tea, wine, kale, oranges, and tomatoes for myricetin; and pears, olive oil, wine, and tomato sauce for isorhamnetin.
Mean intake of total flavonols was 9.6 mg/day. In adjusted models, total flavonol intake was tied with slower decline in the following domains:
- Episodic memory β=0.004, 95% CI 0.002-0.006
- Semantic memory β=0.003, 95% CI 0.001-0.007
- Perceptual speed β=0.003, 95% CI 0.001-0.004
- Working memory β=0.003, 95% CI 0.001-0.005
Total flavonol intake was not associated with change in visuospatial ability.
Among individual flavonol constituents, kaempferol (β=0.01, 95% CI 0.006-0.02) and quercetin (β=0.004, 95% CI 0.0005-0.007) were associated with slower global cognitive decline. Myricetin and isorhamnetin were not associated with global cognition.
The study has several limitations, Holland and colleagues noted. The sample population was white, highly educated, and from the Midwest. In addition, dietary intake was recorded by self-reported food frequency questionnaires. Residual confounding also may have influenced some factors.
Disclosures
The study was supported by the National Institutes of Health, National Institute on Aging, and USDA Agricultural Research Service.
The researchers reported no relevant disclosures.
Source: MedicalNewsToday.com
