Flavonols are a class of antioxidant compounds found in tea, red wine, broccoli, beans, tomatoes, and leeks that have anti-inflammatory properties.
The data, mostly from animal studies, suggest that higher intakes of flavonols may protect against Alzheimer’s disease and dementia.
A recent longitudinal study found that higher dietary intake of flavonols was associated with 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 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. In general, it is known that the vitamins and minerals present in these foods are important. But we now understand that it is the entire composition of the food, including bioactives like flavonols, that makes 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 greens, tomatoes, onions, apples, citrus fruits, and beans. Beverages such as tea and red wine are also important sources of dietary flavonoids.
Previous studies have shown that higher dietary intake of flavonoids is associated with slower cognitive decline that normally occurs with aging and also 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 main 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 the intake of flavonols affect cognitive function?
The present study includes data from 961 participants who reside in Chicago retirement communities and public housing for the elderly and are enrolled in the Rush Memory and Aging Project. The Rush Memory and Aging Project is a longitudinal study whose objective is to identify the factors associated with the deterioration of 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 annually assessed the participants’ cognitive function and risk factors associated with cognitive decline.
To assess cognitive function, a trained technician administered a battery of 19 tests spanning five different cognitive domains. These five areas were:
episodic memory: a form of long-term memory that encompasses memories of events and experiences
semantic memory: a form of long-term memory that encompasses 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 manipulate images mentally.
Based on overall performance on 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 flavonol-containing foods in 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, physical activity level, and participation in activities that enhance cognition. The analyzes suggested that a higher intake of flavonols was associated with a slower decline in general cognitive function.
In this study population, people who ate the most flavonols (an average of 7 servings of dark green leafy vegetables per week) compared to people who ate the least had a 32% decrease in their rate of deterioration cognitive.
2 Antioxidants Linked to Slower Decrease
Furthermore, higher consumption of flavonols (kaempferol and quercetin), but not isorhamnetin or myricetin, was associated with a slower decline in general cognitive function. Looking at changes in specific cognitive domains, the 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 individual flavonol components, higher kaempferol intake was associated with a slower rate of decline in all five cognitive domains. By 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, whereas 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 main sources of other flavanols.
In addition to having beneficial effects on brain health, another recent study reported an association between increased 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.
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cognitive decline leafy vegetable tea