Tea and wine may slow down memory decline, study reveals

According to a new study conducted by researchers from Rush University Medical Center in Chicago, people who consume more foods with antioxidant flavonols may have a slower rate of memory decline.

Flavonols are a type of flavonoid, a group of natural substances found in fruits, vegetables, grains, tea, and wine. Known for their benefits on health, these natural compounds are regarded as an essential component in a wide range of nutraceutical, pharmacological, therapeutic, and cosmetic applications.

961 people with an age average of 81

The study employed 961 people, according to a press release. At an age average of 81 without dementia, the subjects were asked to fill out a questionnaire about how often they consume certain foods. Additionally, they underwent yearly cognitive and memory tests that involved recalling lists of words, remembering numbers, and putting them in the correct order.

In addition, questions regarding their level of education, how much time they spent exercising, and how much time they spent doing mentally stimulating activities like reading and playing games were asked. They were followed for an average of seven years.

And then, the subjects were split into five equal groups based on how many flavonols they had in their diets.

The study population had an average dietary intake of total flavonols of about 10 mg per day, compared to the average amount of flavonols consumed by US adults, which ranges from 16 to 20 milligrams (mg) per day. The highest group ingested an average of 15 mg per day, which is about equivalent to one cup of dark leafy greens, whereas the lowest group consumed only approximately 5 mg daily.

The research team utilized an overall global cognition score that represented the results of 19 cognitive tests to determine rates of cognitive decline. For those with no cognitive issues, the average score was 0.5; for those with mild cognitive impairment, it was 0.2; and for those with Alzheimer's disease, it was -0.5.

Researchers discovered that the cognitive score of those with the highest intake of flavonols fell at a pace of 0.4 units per decade less slowly than those with the lowest intake after adjusting for other variables that may affect the rate of memory decline, such as age, sex, and smoking.

Thomas M. Holland, MD, MS of Rush University Medical Center in Chicago, remarked that this is likely caused by flavonols' innate anti-inflammatory and antioxidant capabilities.

A link between higher amounts of flavonols and slower cognitive decline

Breaking the flavonol into its four constituents - kaempferol, quercetin, myricetin, and isorhamnetin - the research team also found the top food contributors for each category. As per the study paper, they were kale, beans, tea, spinach, and broccoli for kaempferol; tomatoes, kale, apples, and tea for quercetin; tea, wine, kale, oranges, and tomatoes for myricetin; and pears, olive oil, wine, and tomato sauce for isorhamnetin.

"It's exciting that our study shows making specific diet choices may lead to a slower rate of cognitive decline," said study author Holland. "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."

Even though the study points out a link between higher amounts of flavonols and slower cognitive decline, Holland noted this does not prove that flavonols have a direct role in causing a slower rate of cognitive decline.

Another limitation of the study was the food frequency questionnaire was self-reported. Though it's valid, people may not accurately remember what they eat.

The results of the study were published in the journal Neurology on November 22, 2022.

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