A multitude of scientific studies show that what we put on our plates can help to aid memory and slow down age-related cognitive decline.

Researchers at Columbia University and Brigham and Women’s Hospital/Harvard University have conducted a groundbreaking study, providing the first evidence that a diet lacking in flavanols—essential nutrients found in specific fruits and vegetables—contributes to the decline of memory associated with aging.

The study, which involved a large sample size, revealed a clear correlation between the consumption of flavanols and the performance of older adults on memory tests designed to identify age-related memory loss. Furthermore, the researchers discovered that restoring these bioactive dietary components in older adults aged 60 and above, who exhibited a mild deficiency in flavanols, led to notable improvements in their test scores.

“The improvement among study participants with low-flavanol diets was substantial and raises the possibility of using flavanol-rich diets or supplements to improve cognitive function in older adults,” remarks co-lead author Adam Brickman.

The discovery further reinforces the emerging concept that the aging brain necessitates particular nutrients to maintain optimal health, much like the developing brain relies on specific nutrients for its proper growth and development.

“The identification of nutrients critical for the proper development of an infant’s nervous system was a crowning achievement of 20^th century nutrition science,” points out senior author Scott Small. 

“In this century, as we are living longer research is starting to reveal that different nutrients are needed to fortify our aging minds. Our study, which relies on biomarkers of flavanol consumption, can be used as a template by other researchers to identify additional, necessary nutrients.”

Age-Related Memory Decline Tied to Hippocampal Changes

The latest work expands on almost 15 years of research in Small’s lab revealing that flavanols increased function in the brain’s hippocampus, a region crucial for forming new memories, and correlating age-related memory loss to alterations in the dentate gyrus.

Additional studies in mice revealed that flavanols, in particular the flavanol bioactive compound epicatechin, enhanced memory through promoting the development of neurons and blood vessels in the hippocampus.

Then, Small’s team put flavanol supplements to the test on humans. One small study showed that the dentate gyrus is linked to memory loss as people get older. A second, more extensive research revealed that flavanols enhanced memory by working specifically on this brain area and had the greatest effects on those who began with a poor diet.

Researchers from Brigham and Women’s Hospital and Columbia University worked together on the new study to examine how flavanols and multivitamins affected the outcomes of the COSMOS (COcoa Supplements and Multivitamin Outcomes Study). The latest research, COSMOS-Web, aimed to examine whether a lack of flavanols accelerates cognitive aging in this region of the brain by testing the effect of flavanols in a much bigger cohort.

The new study

A randomized trial involving over 3,500 healthy older adults was conducted to examine the effects of a daily flavanol supplement compared to a placebo pill over a period of three years. The active supplement consisted of 500 mg of flavanols, including 80 mg of epicatechins, which is the recommended dietary intake for adults through food sources.

At the beginning of the study, all participants completed a comprehensive survey that evaluated the quality of their diet, specifically focusing on foods known to be rich in flavanols. Additionally, participants engaged in a series of web-based activities from their own homes, specifically designed and validated by Brickman, to assess short-term memory functions associated with the hippocampus. These tests were repeated at yearly intervals throughout the study, covering years one, two, and three. The majority of the participants identified themselves as non-Hispanic and white.

Furthermore, more than a third of the participants provided urine samples, allowing researchers to measure a biomarker indicative of dietary flavanol levels. This biomarker, developed by co-authors from Reading University in the UK, provided a more accurate means of determining the correlation between flavanol levels and performance on cognitive tests. It also ensured that participants adhered to their assigned supplement regimen, as compliance was consistently high throughout the study. While there was some variation in flavanol levels, none of the participants exhibited severe flavanol deficiency.

Flavanol supplementation proved advantageous for individuals with mild flavanol deficiency

For the complete group receiving the daily flavanol supplement, the majority of whom were already consuming a healthy diet rich in flavanols, memory scores improved just little.

But after a year of taking the flavanol supplement, those who said they had a poor diet and had lower levels of flavanols at baseline observed an average rise in their memory scores of 10.5% compared to placebo and 16% compared to baseline. Annual cognitive testing revealed that the improvement shown in the first year was maintained for at least two more years.

The researchers claim that as flavanol intake corresponded with memory scores and flavanol supplementation restored memory in flavanol-deficient people, the data clearly imply that flavanol absence is a driver of age-related memory decline.

The results of the current research support those of a prior study that indicated flavanol pills did not enhance memory in a group of individuals with a variety of baseline flavanol levels. The previous research did not separately examine the impact of flavanol supplementation on patients with low and high flavanol levels.

“What both studies show is that flavanols have no effect on people who don’t have a flavanol deficiency,” according to Small.

It’s also likely that the prior study’s memory tests did not evaluate memory functions in the flavanol-affected region of the hippocampus. According to the latest research, flavanols only enhanced memory functions controlled by the hippocampus; they had no effect on memory processes controlled by other regions of the brain.

“We cannot yet definitively conclude that low dietary intake of flavanols alone causes poor memory performance, because we did not conduct the opposite experiment: depleting flavanol in people who are not deficient,” adds Small says, highlighting that such an experiment might be considered unethical.

According to Small, the subsequent crucial phase to validate the impact of flavanols on the brain involves conducting a clinical trial that focuses on replenishing flavanol levels in adults who exhibit severe flavanol deficiency.

“Age-related memory decline is thought to occur sooner or later in nearly everyone, though there is a great amount of variability,” adds Small. “If some of this variance is partly due to differences in dietary consumption of flavanols, then we would see an even more dramatic improvement in memory in people who replenish dietary flavanols when they’re in their 40s and 50s.”

What are some natural sources of epicatechin?

Epicatechin, a type of flavanol, is widely found in various fruits, including apples, blackberries, broad beans, cherries, grapes, pears, raspberries, as well as in cocoa and tea leaves. It is recognized as one of the most plentiful flavonoids in these natural sources.

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