New research published today in the journal Neurology and supported by the NIH, NIA, and USDA finds the best brain foods to eat and drink to prevent dementia risk and slow cognitive decline.

A study published in the online issue of Neurology® today suggests that people who drink or eat more antioxidant flavonols-rich foods, which are found in many vegetables and fruits as well as tea and wine, may have a slower rate of memory decline.

Study author Thomas M. Holland says “It’s exciting that our study shows making specific diet choices may lead to a slower rate of cognitive decline.

“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.”

Flavonols are a type of phytochemical called a flavonoid. Flavonoids are found in plant pigments and are known to be good for your health.

The study included 961 individuals without dementia with an average age of 81. Every year, they filled out a form about how often they ate certain foods. Additionally, they underwent yearly cognitive and memory assessments that involved putting numbers in the right order, remembering lists of words, and recalling word lists. In addition, questions regarding their level of schooling, how much time they spent exercising, and how much time they spent doing mentally stimulating things like reading and playing video games were asked. They were tracked for 7 years.

According to the amount of flavonols in their diet, the participants were separated into five equal groups. 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 consumed 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.

Scientists developed a global cognition score that included the results of 19 different cognitive tests to estimate rates of cognitive deterioration. People with no thinking problems got a score of 0.5, people with mild cognitive impairment got a score of 0.2, and people with Alzheimer’s disease got a score of -0.5.

After taking into account other things that could affect the rate of memory loss, like age, sex, and smoking, researchers found that people whose flavonol intake was the highest had a cognitive score that dropped by 0.4 units per decade less quickly than those whose intake was the lowest. Holland pointed out that this is likely because flavonols have natural antioxidant and anti-inflammatory qualities.

The study also broke down the flavonol class into its four parts: kaempferol, quercetin, myricetin, and isorhamnetin. Kaempferol is found mostly in kale, beans, tea, spinach, and broccoli; quercetin in tomatoes, kale, apples, and tea; myricetin in tea, wine, kale, oranges, and tomatoes; and isorhamnetin in pears, olive oil, wine, and tomato sauce.

A 0.4-units-per-decade reduction in the rate of cognitive deterioration was observed between the groups with the highest and lowest kaempferol consumption. Cognitive decline was 0.2 units per decade slower among those with the highest consumption of quercetin compared to those with the lowest intake. And individuals with the highest intake of myricetin had a cognitive decline rate that was 0.3 units per decade slower than those with the lowest intake. Isorhamnetin in the diet was not associated with global cognition.

Holland pointed out that while the study does not prove that dietary flavonols directly contribute to a slower rate of cognitive decline, it does demonstrate a relationship between higher intakes of dietary flavonols and a slower rate of cognitive decline.

The self-reported food frequency questionnaire, while valid, may not fully reflect what people consume.

NIH, NIA, and USDA ARS funded the study.