NEW YORK — Sticking to a Western-style diet can exacerbate memory loss during old age, a new study suggests. However, a team from Columbia University in New York says individuals who get their fill of flavanols — nutrients which are abundant in certain fruits, vegetables, and other foods — face a lower likelihood of developing age-related cognitive decline.
The study discovered that replenishing flavanols in mildly deficient individuals over the age of 60 significantly improved their performance on mental tests. This groundbreaking study is the first to establish such a link, potentially paving the way for a new screening program for brain health. It suggests that flavanol supplements could be prescribed to individuals in their 40s and 50s to mitigate the risk of Alzheimer’s disease in later life.
“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 Brickman, PhD, professor of neuropsychology at Columbia University Vagelos College of Physicians and Surgeons and co-leader of the study.
According to projections, the number of dementia cases worldwide will triple to more than 150 million by 2050. This discovery also adds to the evidence suggesting that the aging brain, much like the developing brain in babies, requires specific nutrients for optimal health.
“The identification of nutrients critical for the proper development of an infant’s nervous system was a crowning achievement of 20th century nutrition science,” says the study’s senior author, Scott Small, MD, the Boris and Rose Katz Professor of Neurology at Columbia University Vagelos College of Physicians and Surgeons, in a university release.
“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.”
Scroll down to see all the foods packed with flavanols
The study builds upon more than 15 years of research by the same team, demonstrating that flavanols improve the function of the dentate gyrus, a part of the brain’s hippocampus that is vital for learning and forming new memories. Further experiments in mice discovered that a bioactive substance in flavanols called epicatechin boosts memory by enhancing the growth of neurons and blood vessels.
In the latest research, over 3,500 healthy older adults were randomly assigned to receive a daily supplement or a placebo for three years. The active pill contained 500 mg of flavanols, including 80 mg of epicatechins, a dosage that adults are recommended to obtain from their diet. After the first year of supplementation, participants who consumed a poorer diet and had lower levels of flavanols saw their memory scores increase by an average of 10.5 percent compared to those who took the placebo and 16 percent compared to their baseline memory score.
Annual cognitive testing showed that the improvements observed after one year persisted for at least two more years. The results strongly indicate that a deficiency in flavanols contributes to age-related memory loss, according to the researchers. Flavanol consumption was correlated with memory scores, and flavanol supplements improved memory in flavanol-deficient adults.
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At the beginning of the study, all participants completed a survey assessing the quality of their diet, including foods known to be high in flavanols. They also undertook a series of web-based activities in their own homes, designed and validated by Brickman, to evaluate the types of short-term memory governed by the hippocampus. These tests were repeated after years one, two, and three.
Over a third of the participants also provided urine samples, allowing the researchers to measure a biomarker for dietary flavanol levels, both before and during the study. The memory scores improved only slightly for the entire group taking the daily flavanol supplement, most of whom already consumed a diet rich in flavanols.
These findings align with a recent study that found flavanol supplements did not significantly enhance memory in a group with a variety of baseline flavanol levels. However, this previous study did not separately analyze the effects of flavanol supplements on people 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,” Small says.
Additionally, it is possible that the memory tests employed in the previous study did not effectively assess memory processes in the area of the hippocampus influenced by flavanols.
In the current study, flavanols only improved memory processes governed by the hippocampus and did not enhance memory mediated by other areas 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,” Small says, adding that such an experiment might be considered unethical.
The next step in this research is a clinical trial aimed at restoring flavanol levels in adults with 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,” 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.”
The team’s findings are published in the journal Proceedings of the National Academy of Sciences.
14 foods full of flavanols:
- Dark chocolate and cocoa
- Tea — Both green and black teas contain high levels of flavanols
- Red Wine
- Fava beans
South West News Service writer Mark Waghorn contributed to this report.