People who report eating more foods high in antioxidant flavonols, which are found in several fruits and vegetables, tea, and wine, appear to have slower rates of age-related memory decline, according to a study published in Neurology.
 
“It’s exciting that our study shows making specific diet choices may 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 maintaining their brain health.”
 
The study recruited 961 people with an average age of 81 who did not have dementia. They filled out food frequency questionnaires so that the researchers could determine their flavonol intakes. Annually, they took part in cognitive and memory tests including recalling lists of words, remembering numbers, and putting them in the correct order.
 
The data was also weighed against participants’ education level, how much time they spent doing physical activities, and how much time they spent doing mentally engaging activities such as reading and playing games.
 
The participants were divided into five equal groups based on the amount of flavonols in their diet, with the average flavonol intake being 10 mg per day. The lowest group had an intake of about 5 mg per day, while the highest group consumed about 15 mg per day, the equivalent of about a cup of dark leafy greens.
 
The participants were assessed with global cognition scores which summarized about 19 cognitive tests – the average score ranged from 0.5 for people with no 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 could affect memory decline, those who had the highest intake of flavonols declined at a rate of 0.4 units per decade more slowly than people who had the lowest intake.
 
The flavonol classes were also broken down into the four categories: kaempferol, quercetin, myricetin, and isorhamnetin. The top food contributors 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 intake of kaempferol had a 0.4 units per decade slower rate of cognitive decline compared to those in the lowest group. Those with the highest intake of quercetin had a 0.2 units per decade slower rate of cognitive decline compared to those in the lowest group. And people with the highest intake of myricetin had a 0.3 units per decade slower rate of cognitive decline compared to those in the lowest group. Dietary isorhamnetin was not tied to global cognition.
 
Holland noted that more studies are needed in order to determine any causality from the observational findings, and that while food frequency questionnaires are valid, they were self-reported, which represents a limitation.