To reach their findings, the researchers enrolled 37 healthy individuals aged 50-69 to their study.
For 3 months, some of the participants were randomized to follow a high-flavanol diet, containing 900 mg of flavanols each day. Other participants followed a low-flavanol diet, containing only 10 mg of flavanols a day.
Flavanols were consumed via a cocoa drink produced by food company Mars. The drink - made specifically for research purposes - was produced to contain flavanols that are usually found in raw cocoa, many of which are lost when cocoa is processed. Mars also partly funded the study.
The team found that the participants who followed the high-flavanol diet demonstrated improved function in the dentate gyrus, compared with those who followed the low-flavanol diet. Furthermore, participants in the high-flavanol group performed much better on memory tests.
Dr. Small comments:
"If a participant had the memory of a typical 60-year-old at the beginning of the study, after 3 months that person on average had the memory of a typical 30- or 40-year-old."
The team stresses that the cocoa drink used in this study is not the same as chocolate. Because chocolate has been processed, it does not contain flavanols at high levels like the raw cocoa used to make the drink in this research. Therefore, the team warns against increasing chocolate consumption to improve memory.