A large-scale study led by researchers at Columbia University and Brigham and Women’s Hospital/ Harvard University, abbreviated as COSMOS-Web, found that a diet deficient in flavanols was established as a driver of age-related memory loss.
 
Flavanols are a class of bioactive compounds found in plant-based components of the diet, including cocoa.
 
Just as the developing brain needs specific nutrients for proper growth, the aging brain needs a specific combination of nutrients for optimal health, according to the authors.  “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 Adam Brickman, PhD, professor of neuropsychology at Columbia University Vagelos College of Physicians and Surgeons and co-leader of the study.
 
“The identification of nutrients critical for the proper development of an infant’s nervous system was a crowning achievement of 20th century nutrition science,” said 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 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.”
 
Study Details
 
The present study was conducted in partnership with the research team behind the COSMOS-Mind study, a cross-sectional evaluation of whether multivitamin-mineral and/or cocoa supplementation was associated with improved cognition.
 
In a population of 3,500 older adults representing the cocoa portion of the study who underwent additional testing, intake of a 500 mg dose of cocoa flavanols daily including 80 mg of epicatechins was linked to improvements in a series of web-based activities to assess short-term memory. The tests, which were designed specifically for this study, were repeated over the course of three years in which participants took either cocoa flavanols or a placebo.
 
At baseline, all participants completed a survey that assessed the quality of their diet, including foods known to be high in flavanols. Additionally, more than a third of the participants supplied urine samples which allowed researchers to measure a biomarker for dietary flavanol levels, both before and during the intervention.
 
This biomarker gave researchers a more precise way to determine if flavanol levels corresponded to performance on the cognitive tests and if deficiency at baseline was linked to more significant improvements.
 
Flavanol Deficiencies are an Important Biomarker
 
In the group of participants which had a healthy flavanols intake, memory scores only improved slightly, but those with a poorer diet characterized by a deficient intake of flavanols saw an average 10.5% improvement in memory scores compared to the placebo, and a 16% improvement compared to their own scores at baseline. The improvement in scores at one year was sustained for the remaining two years of the study, the researchers noted.
 
According to the authors, the evidence is strong that flavanol deficiency is a driver of age-related memory loss. The results were also consistent with those of COSMOS-Mind, in that cocoa flavanols didn’t have a significant effect in a population that was, on average, non-deficient in flavanols. In COSMOS-Mind, researchers didn’t separately evaluate the effects of flavanol supplements in those with low and high baseline levels.
 
“What both studies show is that flavanols have no effect on people who don’t have a flavanol deficiency,” Small said. He noted that it’s also possible that memory tests used in the previous study didn’t assess memory processes in the area impacted by flavanols. Flavanols only improved memory processes governed by the hippocampus and didn’t improve memory mediated by other areas of the brain.
 
Hagen Schroeter, PhD, noted that the study had a unique strength thanks to the use of a urine biomarker produced by the body only after flavanols consumption. Schroeter is the chief science officer at Mars Edge, which provided funding for the study.
 
“The urine biomarker is a substance created by the body following consumption of flavanols – measuring it enabled researchers for the first time to assess flavanol intake accurately and objectively, and without the need for food diaries. The biomarker was identified and validated in a multi-year collaboration between Mars Edge and its academic partners and published in a series of scientific papers. Mars Edge is proud to have provided a novel tool that allowed COSMOS-Web researchers to investigate at scale and in detail the link between flavanol intake and age-related memory.” 
 
Background
 
The current study builds on 15 years of research in Small’s lab which has linked age-related memory losses to changes in the dentate gyrus, which is a specific area of the hippocampus. This previous research indicated that flavanols were active within this specific region.
 
Research in mice also found that flavanols, particularly a type called epicatechin, improved memory by enhancing the growth of neurons and blood vessels in the hippocampus.
 
Small’s team followed this research by testing flavanol supplements in people. In a small study, it was confirmed that the dentate gyrus is linked to cognitive aging, while a larger study showed that flavanols improved memory by acting selectively in this brain region and had the most activity in those who had poor diet quality.
 
Next Steps
 
“We cannot yet definitely 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, noting that such a study might be considered unethical. The next step is to determine the effect of flavanols observed specifically in a population of 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,” said 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.”