Flavonols are a class of antioxidant compounds found in tea, red wine, broccoli, beans, tomatoes, and leeks that have anti-inflammatory properties.
Data, mostly from animal studies, suggests that higher intake of flavonols may protect against Alzheimer’s disease and dementia.
A recent longitudinal study found that a higher dietary intake of flavonols was linked to a slowing of age-related decline in general and specific areas of cognitive function.
A recent study published in Neurology shows that a higher intake of flavonols, a category of flavonoids found in fruits, vegetables, tea, and wine, was associated with slower cognitive decline in older adults. The study adds to the limited but growing data showing an association between dietary flavonol intake and brain health.
A healthy diet containing a variety of fruits and vegetables is essential for good health, especially brain health. It is generally known that the vitamins and minerals present in these foods are important. But we now understand that it’s the entire composition of the food, including the bioactives like flavonols, that make these foods beneficial.
Flavonoids and brain health
Flavonoids are a class of compounds produced by plants that possess antioxidant and anti-inflammatory properties. Flavonoids are found in commonly eaten fruits and vegetables, including berries, cherries, leafy vegetables, tomatoes, onions, apples, citrus fruits, and beans. Beverages such as tea and red wine are also important sources of flavonoids in the diet.
Previous studies have shown that a higher dietary intake of flavonoids is associated with slower cognitive decline that normally occurs with aging as well as due to Alzheimer’s disease. These effects of flavonoids have been attributed to their ability to reduce oxidative stress, decrease inflammation in the brain, and increase brain plasticity.
There are six major subclasses of flavonoids, namely flavonols, flavan-3-ols, flavanones, flavones, isoflavones, and anthocyanins. Additionally, several compounds make up each subclass of flavonoids. For example, flavonols include compounds such as quercetin, kaempferol, isorhamnetin and myricetin. Although animal studies suggest a beneficial impact of certain flavonols and their individual components on cognition, similar data from human studies is limited.
Does flavonol intake affect cognitive function?
The present study includes data from 961 participants residing in retirement communities and public housing for the elderly in Chicago and enrolled in the Rush Memory and Aging Project. The Rush Memory and Aging Project is a longitudinal study whose goal is to identify the factors associated with the decline in cognitive and motor functions caused by aging and Alzheimer’s disease. Participants were between the ages of 58 and 100 and had not been diagnosed with dementia at the time of enrollment. The researchers assessed participants’ cognitive function and risk factors associated with cognitive decline on an annual basis.
To assess cognitive function, a trained technician administered a battery of 19 tests encompassing five different cognitive domains. These five areas were:
episodic memory: a form of long-term memory encompassing memories of events and experiences
semantic memory: a form of long-term memory encompassing factual and conceptual knowledge
working memory: a form of short-term memory that temporarily stores and manipulates information
perceptual speed: the ability to quickly process visual information
visuospatial ability: ability to perceive spatial relationships and mentally manipulate images.
Based on the overall performance of the 19 cognitive tests, the researchers quantified each participant’s overall cognitive function.
To assess dietary intake of flavonols and individual flavonol components, the researchers used a standardized questionnaire to estimate the frequency of consumption of foods containing flavonols over the past year. The researchers then examined the association between dietary flavonol intake and cognitive function after adjusting for factors associated with cognitive decline, including age, gender, education level, smoking status, activity level. physical activity and engagement in cognition-enhancing activities. Analyzes suggested that higher flavonol intake was associated with a slower decline in overall cognitive function.
In this study population, people who consumed the most flavonols (an average of 7 servings of dark green leafy vegetables per week) compared to people who consumed the least had a 32% decrease in their rate of cognitive decline.
2 Antioxidants Linked to Slower Decline
Additionally, higher consumption of flavonols (kaempferol and quercetin), but not isorhamnetin or myricetin, was associated with a slower decline in overall cognitive function. Looking at changes in specific cognitive domains, researchers found that higher flavonol intake was associated with slower declines in episodic memory, semantic memory, perceptual speed, and working memory. , but not visuospatial ability.
Among the individual flavonol components, higher kaempferol intake was associated with a slower rate of decline in all five cognitive domains. In contrast, myricetin was not associated with a change in cognitive abilities, but was suggestive for working memory. Quercetin consumption was associated with a more gradual decline in episodic and semantic memory, while isorhamnetin consumption was correlated with a more gradual decline in episodic and suggestive memory for visuospatial memory.
Leafy vegetables are the richest source of kaempferol. Tea, onions, leeks, broccoli, beans, tomatoes, and berries are some of the other major sources of other flavanols.
In addition to having beneficial effects on brain health, another recent study reported an association between a higher intake of flavonoids, including flavonols, and a marker of subclinical atherosclerosis. This further highlights the potential protective effects of flavonoids on not only brain health but also cardiovascular health.
