Flavanols May Help Protect Against Age-Related Cognitive Decline

According to the researchers replenishing flavanols in older adults aged 60+ improved their performance in testing, and they suggest that supplementing flavonols to those in their 40s and 50s may help to lower the risk of developing Alzheimer’s disease later in life. Additionally, this may be the first study to reveal that flavonoid deficiency may be a way to screen for brain health. 

“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,” says Adam M. Brickman, Ph.D., professor of neuropsychology at Columbia University Vagelos College of Physicians and Surgeons and co-leader of the study.

This study builds on over 15 years of previous research linking age-related memory loss to changes in the dentate gyrus within the hippocampus, showing that flavanols improved function in this brain region. In other mice research epicatechin flavanols were shown to improve memory by enhancing the growth of neurons and blood vessels in the hippocampus. Additional testing using flavanol supplements in humans confirmed the dentate gyrus link to cognitive aging, and a second trial demonstrated that flavonols improved memory by acting selectively on this brain region with the most impact on those who started out with a poor quality diet.

In this study over 3,500 healthy older adults were randomly assigned with a placebo or flavanol supplement to take daily for 3 years. The supplement contained 500mg of flavanols which included 80mg of epicatechins. The participants completed surveys at the beginning of the study to assess their diet, and they also performed a series of testing to assess short-term memory; testing was repeated at the end of every year. 

Over one-third of the participants also supplied urine samples to measure biomarkers of dietary flavanol levels. This biomarker provided a more precise way to determine if the flavanol levels corresponded to participant performance during cognitive testing as well as ensuring that the participants were adhering to their assigned regimen. According to the researchers, participant compliance was high throughout the study, and flavanol levels varied moderately but none of the participants were severely flavanol deficient. 

Memory scores were observed to improve slightly for the entire group taking the flavanol supplement, however, most of this group was already following a healthy diet rich in flavanols. But at the end of the first year, those following a poor diet with the lowest baseline level of flavanols experienced increases of an average of 10.5% compared to their peers in the placebo group, and a 16% increase compared to their baseline memory. The researchers reported that the annual cognitive testing demonstrated that the improvement observed at one year was sustained for at least two more years. 

The researchers suggest that their findings strongly indicate that flavanol deficiency is a driver of age-related memory loss because flavanol consumption was found to correlate with memory scores and flavanol supplements and improve memory in flavanol-deficient adults. Additionally, the findings from this study are consistent with another study.

 “What both studies show is that flavanols have no effect on people who don’t have a flavanol deficiency,” Small says. Small says that next, they would like to conduct a clinical trial to restore flavanol levels in adults with severe flavonol deficiency to confirm the effects on 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,” said Small.

“Age-related memory decline is thought to occur sooner or later in nearly everyone, though there is a great amount of variability,” says 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.”

Recently flavanols were investigated in another study, this one is published in the American Journal of Clinical Nutrition, and it suggests that eating more plant-based foods that contain dietary compounds called flavonoids can help to lower your chances of developing frailty, and foods such as apples and blackberries that contain quercetin flavonoids may be the most important for frailty prevention.

Flavanols are a naturally occurring sub-group of flavonoids found within plants which includes tea, apples, grapes, red wine, cocoa, scallions, and various berries. Flavanols give fruits and vegetables their bright colours, and they are believed to contribute to the antioxidant and cardioprotective effects of these types of foods. Additionally, each plant food can contain more than one type of flavanol along with other complementing micronutrients which is why many nutritionists recommend “eating the rainbow” of coloured foods every day.