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Diet quality and increased flavanol intake may be linked to improved memory

  • A 20-week, randomized, controlled trial in 211 healthy adults aged 50-75 has shown that increasing flavanol intake improved performance on list-learning memory tasks
  • Those with habitual lower diet quality were more likely to experience improved memory following increased flavanol intake, compared to a placebo

Release Date: Monday 15 February 2021

Diet quality and dietary flavanol intake may impact age-related memory function in normal cognitive aging, new research published in Scientific Reports has found.

Researchers at Columbia University’s Irving Medical Centre, in collaboration with Mars scientists, conducted the randomized, double-blind, placebo-controlled trial to assess the impact of diet on cognitive aging. The trial investigated the effects of a daily placebo, 260 mg, 510 mg or 770 mg cocoa flavanol supplement for 12 weeks, followed by an eight-week washout period, during which participants returned to their typical diet.

Researchers evaluated the typical diets of 211 healthy adults aged 50-75 using the alternative Healthy Eating Index (aHEI). The aHEI assesses the amount of fruits, vegetables, whole grains and the balance of other foods in an individual’s diet. When interpreting the outcomes of this study, participants were sorted into groups representing those in the top, middle, and lower third of diet quality. Participants in the lower category still had a higher quality diet than half of U.S. general public.

The team also measured a recently validated novel biomarker in blood, which allowed for an objective assessment of each participant’s typical flavanol intake. Flavanols are bioactive compounds naturally present in foods such as tea, apples, cocoa, pome fruits, grapes and berries, that are widely investigated for their role in health and nutrition.

Participants completed a series of tasks involving areas of the brain thought to be important in cognitive aging. A newly developed object-recognition task targeted the dentate gyrus, a specific region within the hippocampus previously indicated to be sensitive to flavanol interventions. Previously established list-learning and list-sorting tasks targeted the hippocampus and prefrontal cortex, respectively.

At baseline, prior to the dietary flavanol intervention, participants with a higher diet quality and higher habitual flavanol intake performed better on list-learning memory tests related to the hippocampus, and reflective of episodic memory. List-sorting memory performance related to the prefrontal cortex was not associated with a persons’ habitual diet quality or flavanol intake at baseline.

After the intervention, those consuming 770mg of cocoa flavanols daily for 12 weeks performed significantly better in the list-learning task, compared to the placebo group. The effects were seen even when participants’ age, sex and level of education were accounted for. This further supports the interpretation that the flavanol intake was a driving factor for memory improvements observed. Generally, those with lower diet quality were more likely to experience improved memory following the flavanol intervention.

Eight weeks after stopping the flavanol intervention, list-learning performance returned to pre-intervention levels, a finding that also supports the relevance of flavanols in this context.

Consistent with the findings at baseline, the prefrontal cortex-dependent task was unaffected by the flavanol intervention. Performance on the new object recognition task was not linked to diet quality and did not improve with flavanol intake. Analysis suggested this task may have been too difficult for older participants.

This investigation builds on previous research into the benefits of flavanols in cognition. While this study is one of the larger controlled dietary intervention studies in nutrition and cognitive aging to date, as with almost all study of this kind, it’s scale and duration does not reflect the general population. In this context, results from cognition assessments that are part of the Cocoa Supplement and Multivitamins Outcomes Study (COSMOS) may provide replication at scale. COSMOS is a five-year trial investigating the health impact of cocoa flavanols in a cohort of 22,000 healthy people. Results from COSMOS are expected later this year.

Professor Scott Small, Professor of Neurology at Columbia University, who led the study said:

"It was very interesting to find that participants with lower diet quality and lower flavanol intake in this study were more likely to experience the largest effects on memory. To think that if someone with such a diet, which represents more than 50% of US population, improved their habitual diet and flavanol intake, could potentially experience a jump in their memory and cognitive performance, is intriguing. It will be very interesting to see if our findings could replicate at the scale of the population, which is why we are awaiting with great interest the outcomes of the cognitive assessments that are part of the Cocoa Supplement and Multivitamin Outcomes Study (COSMOS)."

Dr Hagen Schroeter, Chief Science Officer at Mars Edge, a business segment within Mars dedicated to nutrition, said:

"This study builds on previous research looking at cognitive benefits of flavanol intake and provides encouraging evidence of the importance of nutrition, and support for the identification of possible dietary approaches to promote healthy cognitive function as we age."

– Ends –

This study was supported with an unrestricted grant from Mars, Incorporated and co-funded by the Nathanial Wharton Fund. One co-author is an employee of Mars.

Scientific Reports: Insights into the role of diet and dietary flavanols in cognitive aging: results of a randomized controlled trial

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