Summary: Increased consumption of foods and beverages rich in antioxidant flavonols helps slow memory and cognitive decline, a new study reports.
People who eat or drink more foods with antioxidant flavonols, which are found in various fruits and vegetables as well as tea and wine, may have a slower rate of memory decline, according to a study published in the issue in line of November 22, 2022 from Neurology.
“It is exciting that our study 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 play an active role in maintaining their brain health.”
Flavonols are a type of flavonoid, 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 filled out a questionnaire each year about how often they ate certain foods. They also completed annual memory and cognitive tests that included recalling lists of words, recalling 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 engaging 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 amount of flavonol intake in US adults 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 around 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 rates of cognitive decline, the researchers used an overall global cognition score that summarizes 19 cognitive tests. The mean score ranged from 0.5 for people without thinking problems, 0.2 for people with mild cognitive impairment, and -0.5 for people with Alzheimer’s disease.
After adjusting for other factors that could affect the rate of memory decline, such as age, gender, and smoking, the researchers found that the cognitive score of people with the highest intake of flavonols decreased at a rate of 0. 4 units per decade more slowly than people whose intake was the lowest. Holland noted that this is likely due to the inherent antioxidant and anti-inflammatory properties of flavonols.
The study also divided the flavonol class into four components: kaempferol, quercetin, myricetin, and isorhamnetin.
The top contributing foods 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 with the highest kaempferol intake had a 0.4 unit per decade slower rate of cognitive decline compared with those in the lowest group. Those with the highest quercetin intake had a 0.2 unit per decade slower rate of cognitive decline compared to those in the lowest group. And people with the highest myricetin intake had a 0.3 unit per decade slower rate of cognitive decline compared with those in the lowest group. Dietary isorhamnetin was not linked to global cognition.
Holland noted that the study shows an association between higher amounts of flavonols in the diet and slower cognitive decline, but it doesn’t prove that flavonols directly cause a slower rate of cognitive decline.
Other limitations of the study are that the food frequency questionnaire, while valid, was self-reported, so people may not accurately remember what they eat.
Money: The study was supported by the National Institutes of Health, the National Institute on Aging and the USDA Agricultural Research Service.
About this research news on diet and memory
Author: natalia conrad
Contact: Natalie Conrad–ON
Image: The image is in the public domain.
original research: Findings will appear on Neurology