Too soon to tell if chocolate is brain food, experts say

Recent research suggesting that compounds found in cocoa can improve memory in older people makes old age seem not quite so bad. But is it too soon to start plying grandma with a family-sized block of chocolate every time you go to visit?

A number of experts have cautioned against getting too carried away with these results. They say that the theory needs to be further tested before we start labelling chocolate as ‘brain food’.

The study found that giving elderly people high doses of flavanols from cocoa boosts blood supply to the dentate gyrus, an area of the brain, which helped them perform better in a memory task than those given only a low dose.

“This well-designed but small study suggests the antioxidants found in cocoa can improve cognitive performance by improving blood flow to a certain region of the brain. This brain region is known to be affected in ageing, but as yet we don’t know whether these brain changes are involved in dementia,” said Dr Clare Walton, research manager, Alzheimer’s Society.

“With the winter nights setting in, many of us will be settling down with a nice hot cup of cocoa at the end of our day. However, the jury is still out as to whether partaking in things high in antioxidants can improve your memory or reduce your risk of dementia.”

“Although promising, the results should be interpreted with caution for several reasons including: group sizes were small (only 37 participants overall); there were small differences in caffeine and theobromine levels in the high and low flavanol cocoa sachets making it possible that substances other than flavanols mediated the effects; only reaction times, and not accuracy of performance, were actually improved and being faster without being more accurate is not always an advantage; and finally, it is not clear that memory is directly improved, perhaps instead participants are just paying better attention to the task,” added Dr Liz Coulthard, Consultant Senior Lecturer in Dementia Neurology, University of Bristol.

“It would be very exciting if such a cognitive benefit of flavanols were shown in a larger study that probed several aspects of cognition.”

“This very small trial highlights some possible effects of flavanols found in cocoa beans over a short time period, but we’d need to see much longer, large-scale studies to fully understand whether a diet high in these flavanols could boost cognition in old age. We also don’t know how meaningful the improvements measured in the tests used here would be for people in their daily lives. This study didn’t look at dementia, and we can’t know from this research whether a diet high in cocoa would have any effect in either preventing or delaying the onset of the condition. The supplement used in this study was specially formulated from cocoa beans, so people shouldn’t take this as a sign to stock up on chocolate bars,” said Dr Simon Ridley, head of research at Alzheimer’s Research UK.

The research paper, ‘Enhancing dentate gyrus function with dietary flavanols improves cognition in older adults’, by Brickman et al. was published in Nature Neuroscience on 26 October.