Flavanols are found in tea, grapes, red wine, apples and cocoa products. Last week, a study led by scientists at Columbia University Medical Center reveals that dietary cocoa flavanols which are the naturally occurring bioactives in cocoa reversed age-related memory decline in healthy older adults. The study published in Nature Neuroscience is considered to include the first direct evidence that one component of age-related memory decline in humans is caused by changes in a specific region of the brain and also that this form of memory decline can be improved by a dietary intervention.
For the study, 37 volunteers age 50 to 69 received a high-flavanol diet of 900 milligrams of flavanols a day or a low-flavanol diet of 10 milligrams a day for three months. A cocoa flavanol-containing test drink was prepared using a proprietary process to extract flavanols from cocoa beans. It was pointed out though that the product used is not the same as chocolate and the researchers do not advise chocolate consumption to gain this effect. The volunteers were also administered brain imaging and memory tests before and after the study.
When we imaged our research subjects brains, we found noticeable improvements in the function of the dentate gyrus in those who consumed the high-cocoa-flavanol drink, said lead author Adam M. Brickman, PhD., associate professor of neuropsychology at the Taub Institute.
The high-flavanol group also performed significantly better on the memory test, according to senior author Scott A. Small, MD. If a participant had a memory of a typical 60 year old at the beginning of the study, after three months that person on average had the memory of a typical 30 or 40 year old, Small said. But the findings need to be replicated in a larger study which Small and his team have plans for.
Flavanols are also found naturally in tea leaves and certain fruits and vegetables. Overall amounts and specific forms and mixtures vary widely. Exercise has also been shown in previous studies - including Dr. Smalls - to improve memory and dentate gyrus function in younger people. In the current study, the researchers were unable to assess whether exercise had an effect on memory or on dentate gyrus activity. "Since we didn't reach the intended VO2max (maximal oxygen uptake) target," said Dr. Small, "we couldn't evaluate whether exercise was beneficial in this context. This is not to say that exercise is not beneficial for cognition. It may be that older people need more intense exercise to reach VO2max levels that have therapeutic effects."
Cocoa Flavanols And Cognitive Impairment
In an August 2012 study published in the American Heart Associations journal Hypertension, it was reported that eating cocoa flavanols daily may improve mild cognitive impairment. For this study, 90 elderly participants with mild cognitive impairment were randomized to drink daily either 990 milligrams (high), 520 milligrams (intermediate) or 45 milligrams (low) of a dairy-based cocoa flavanol drink for eight weeks. The diet was restricted to eliminate other sources of flavanols from foods and beverages other than the dairy-based cocoa drink.
Researchers found that scores significantly improved in the ability to relate visual stimuli to motor responses, working memory, task switching and verbal memory for those drinking the high and intermediate flavanol drinks. Participants drinking daily higher levels of flavanol drinks had significantly higher overall cognitive scores than those participants drinking lower levels. Insulin resistance, blood pressure and oxidative stress also decreased in those drinking high and intermediate levels of flavanols daily. Changes in insulin resistance explained about 40 percent of the compositive scores for improvements in cognitive functioning.
This study provided encouraging evidence that consuming cocoa flavanols as part of a calorie-controlled and nutritionally- balanced diet could improve cognitive function.