Overview: Increasing consumption of foods and drinks high in antioxidant flavonols helps slow memory and cognitive decline, a new study reports.
According to a study published in the November 22, 2022 online issue, people who eat or drink more foods containing antioxidant flavonols, which are found in several fruits and vegetables, as well as tea and wine, may have slower memory decline. Neurology.
“It’s exciting that our research shows that making specific dietary choices can lead to a slower rate of cognitive decline,” said study author Thomas M. Holland, MD, MS of Rush University Medical Center in Chicago.
“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 keeping their brains healthy.”
Flavonols are a type of flavonoids, a group of phytochemicals found in plant pigments known for their beneficial health effects.
The study involved 961 people with an average age of 81 without dementia. They completed a questionnaire each year about how often they ate certain foods. They also completed annual cognitive and memory tests, which included memorizing word lists, remembering numbers, and putting them in the correct order.
They were also asked about other factors such as their level of education, how much time they spent in physical activities, and how much time they spent in mentally appealing activities such as reading and playing games. They were followed for an average of seven years.
The people were divided into five equal groups based on the amount of flavonols they had in their diet. While the average intake of flavonol in adults in the US is approximately 16 to 20 milligrams (mg) per day, the study population had an average dietary intake of total flavonols of approximately 10 mg per day.
The lowest group had an intake of about 5 mg per day and the highest group consumed an average of 15 mg per day; which is equivalent to about a cup of dark leafy greens.
To determine the rate of cognitive decline, researchers used an overall global cognition score that summarized 19 cognitive tests. The mean score ranged from 0.5 for people without thinking problems to 0.2 for people with mild cognitive impairment to -0.5 for people with Alzheimer’s disease.
After adjusting for other factors that can influence the rate of memory loss, such as age, gender and smoking, researchers found that the cognitive score of people with the highest flavonol intake declined more slowly at a rate of 0.4 units per decade than people whose the lowest intake. Holland noted that this is likely due to the inherent antioxidant and anti-inflammatory properties of flavonols.
The study also split the flavonol class into its four constituents: kaempferol, quercetin, myricetin and isorhamnetin.
The top food contributors for each category 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.
People who had the highest kaempferol intake had 0.4 units per decade slower cognitive decline compared to those in the lowest group. Those with the highest quercetin intake had 0.2 units per decade slower cognitive decline compared to those in the lowest group. And people with the highest myricetin intake had a 0.3 units per decade slower cognitive decline compared to those in the lowest group. Dietary isorhamnetin was not tied to global cognition.
Holland noted that the study shows an association between higher amounts of dietary flavonols and slower cognitive decline, but does not prove that flavonols directly cause slower cognitive decline.
Other limitations of the study are that the food frequency questionnaire, while valid, was self-reported, so people may not remember exactly what they eat.
financing: The study was supported by the National Institutes of Health, National Institute on Aging and USDA Agricultural Research Service.
About this news about nutrition and memory research
Author: Natalie Conrad
Contact: Natalie Conrad – ON
Image: The image is in the public domain
Original research: The findings appear in Neurology