Summary: Higher dietary intake of antioxidant flavonols is associated with a slower rate of memory and overall cognitive decline in older adults, according to new research.
Source: AAN
A large observational study reports that people who consume more foods and beverages rich in flavonols—antioxidant compounds found in many fruits, vegetables, tea and some wines—tend to experience a slower decline in memory and cognitive performance over time. The findings were published online in Neurology on November 22, 2022.
“It’s encouraging that specific, achievable dietary choices may be linked with a reduced rate of cognitive decline,” said study author Thomas M. Holland, MD, MS, of Rush University Medical Center in Chicago. “Simple changes such as increasing fruit and vegetable intake and drinking more tea are practical steps people can take to support brain health.”
Flavonols are a subclass of flavonoids—plant-derived phytochemicals with antioxidant and anti-inflammatory properties. The study explored whether higher habitual intake of total flavonols and of four specific flavonol compounds was associated with slower declines on detailed cognitive testing.
Researchers followed 961 adults without dementia, with an average age of 81 at baseline. Participants completed an annual food-frequency questionnaire about how often they consumed various foods and beverages, and they underwent comprehensive annual cognitive testing. The cognitive battery included 19 tests covering memory, attention, executive function and language, and produced a composite global cognition score. Scores ranged roughly from 0.5 (no impairment) to -0.5 (Alzheimer’s-level impairment) in this cohort. Participants also provided information on education, physical activity, and mentally engaging activities such as reading and games. The average follow-up period was seven years.
Study participants were divided into five groups based on their total dietary flavonol intake. While typical U.S. adult intake is estimated at 16–20 mg per day, this cohort averaged about 10 mg per day. The lowest quintile averaged about 5 mg per day and the highest about 15 mg per day—roughly the amount found in one cup of dark leafy greens.
After adjusting for potential confounders including age, sex and smoking, researchers found that participants in the highest flavonol intake group had a slower decline in global cognition—about 0.4 units per decade—compared with those in the lowest intake group. The authors attribute this association to the known antioxidant and anti-inflammatory effects of flavonols, which may protect neurons and brain function over time.
The analysis also examined four individual flavonols: kaempferol, quercetin, myricetin and isorhamnetin. Key dietary contributors identified in the study included:
- Kaempferol: kale, beans, tea, spinach and broccoli.
- Quercetin: tomatoes, kale, apples and tea.
- Myricetin: tea, wine, kale, oranges and tomatoes.
- Isorhamnetin: pears, olive oil, wine and tomato sauce.
Comparing highest versus lowest intake groups, the investigators reported a slower cognitive decline of 0.4 units per decade for kaempferol, 0.2 units per decade for quercetin, and 0.3 units per decade for myricetin. Dietary isorhamnetin was not associated with global cognition in this analysis.
The authors emphasize that the study demonstrates an association, not causation. Although the findings support a potential protective role of flavonol-rich foods for cognitive aging, randomized clinical trials would be needed to establish a direct causal effect. Other limitations include reliance on a self-reported food-frequency questionnaire, which can introduce recall bias and measurement error despite validation.
Practical takeaways from this research include increasing intake of flavonol-containing foods—such as leafy greens, certain fruits, beans, tea and moderate wine for those who already drink—as part of a balanced diet. These foods offer additional nutritional benefits beyond flavonols and may contribute to overall brain and cardiovascular health.
Funding: This research was supported by the National Institutes of Health, the National Institute on Aging, and the USDA Agricultural Research Service.
About this diet and memory research news
Author: Natalie Conrad
Source: AAN
Contact: Natalie Conrad – AAN
Image: The image is in the public domain
Original Research: The findings will appear in Neurology