Antioxidant flavanols associated with slower cognitive decline

Those who consume more foods and drinks with antioxidant flavanols may have slower memory decline, according to a recent study.

The study, published in the journal, Neurology, was led by Thomas Holland, MD, of Rush University Medical Center in Chicago. Previous studies have shown flavanols, a group of phytochemicals found in plant pigments, to have beneficial effects on cognition. For his study, Holland and his colleagues set out to better understand the association between dietary intake of flavanols and memory.

Included in the study were 961 people with an average age of 81 who did not have dementia. Participants were followed for an average of seven years. Every year they completed cognitive and memory tests which involved exercises like recalling lists of words and remembering numbers and putting then in the correct order. In addition, participants were surveyed on how often they ate certain foods, their level of education, time spent exercising, and how often they did mentally engaging activities.

The participants were split into five equal groups based on how much flavanols were included in their diet. The study population had an average of 10 milligrams (mg) of flavanols a day. The lowest group had 5 mg of flavanols a day, and the highest group consumed 15 mg per day.

To determine the participants’ rate of memory decline, researchers used an over-all global cognition score which took all 19 cognitive test results into consideration, and adjusted results for age, sex, and smoking status. The average score ranged from 0.5 units for people with no cognitive problems, to 0.2 units for those with mild cognitive impairment, to -0.5 units for those who were diagnosed with Alzheimer’s disease.

Results showed that the memory of those with the highest intake of flavanols declined at a rate of 0.4 units per decade slower than those with the lowest intake. Researchers then broke the flavanol class down into the four constituents including, kaempferol, quercetin, myricetin, and isorhamnetin. Kaempferol, which is found in foods like tomatoes, kale, apples, and tea, was the most effective in slowing memory loss.

According to the study’s authors, these results suggest that simple dietary choices could help prevent memory loss in old age.

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