We don’t have to be told a diet rich in fruit and vegetables is good for our health; it may be one of the few areas of science generally not up for debate, even if our adherence to the advice varies greatly.
But in a first-of-its-kind study, scientists have seemingly cemented the connection between a diet deficient in flavanols – a plant-based compound known for its antioxidant benefits, among others – and age-related memory loss. What’s more, they found that boosting a poor diet with flavanol supplements could be key in reversing this memory loss.
It supports the growing consensus among scientists that, much like developing brains in childhood, aging brains require specific nutrition to stave off cognitive decline.
“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,” said Dr Adam Brickman, professor of neuropsychology at Columbia University.
The sizeable study conducted by scientists from Columbia University and Brigham and Women's Hospital/Harvard tracked more than 3,562 healthy adults with an average age of 71. At the beginning of the three-year study, participants assessed their own diets and completed a set of short-term memory tasks designed to trigger the hippocampus region of the brain.
Participants were then randomly chosen to receive either a placebo or a supplement containing 500 mg of flavanols, including 80 mg of epicatechins, which in the past five years have been increasingly linked to brain function, metabolism, lean muscle maintenance and cardiovascular health.
The memory tests, which were web-based and took place in the participants’ homes, were repeated every 12 months for three years. Urine testing also ensured flavanol levels were in line with the study’s baseline data and accurately reflected the cohort taking the supplements (however, the study notes excellent compliance by participants).
At the end of the first year, those who reported a flavanol-deficient diet and were prescribed the supplement, saw their memory scores boosted by 10.5% compared to those taking the placebo, and 16% compared to their baseline memory results. The improvements were sustained across the three-year study.
And perhaps some good news for those who already get their fill of flavanols: the participants who weren’t deficient in this area got no significant benefit from the supplements.
“Age-related memory decline is thought to occur sooner or later in nearly everyone, though there is a great amount of variability,” said Scott Small, Professor of Neurology at Columbia University. “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 study builds on 15 years of research by Small and his colleagues looking at linkages between changes in the dentate gyrus – a specific area in the learning and memory epicenter, the hippocampus – and age-related memory loss, and how flavanols can boost executive function.
The team had already established through mouse models that epicatechin in flavanols enhanced neuron and blood vessel health in the hippocampus. Several more trials have found links between the compound and cognition, with this latest one showing the most resounding correlation.
“In this century, as we are living longer research is starting to reveal that different nutrients are needed to fortify our aging minds,” said Small. “Our study, which relies on biomarkers of flavanol consumption, can be used as a template by other researchers to identify additional, necessary nutrients.”
Flavanols occur naturally in many plant-based foods, including leafy green vegetables, berries, apples, onions, citrus, grapes, tomatoes, broccoli, lettuce, tea, chocolate and red wine. While the amount varies depending on quality, 20 g of dark chocolate yields around 35 mg of flavanols, a medium-sized apple has 10 mg. The daily recommended amount is 500 mg.
While the study supported the researchers’ hypothesis that lower flavanol consumption can drive poorer age-related memory function, Small is quick to note that further work is needed to prove causation over correlation.
“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 said, who also questioned the ethics of this as a human trial.
Instead, the researchers will look at a clinical trial that aims to restore memory function in older adults with severe flavanol deficiencies.
It follows on from a 2022 study that linked an increased flavanol intake with slower cognitive decline.
The research was published in the journal PNAS.
Source: Columbia University