Chocolate’s memory-boosting powers

Good news for chocoholics – chocolate can boost memory. The bad news is that you would have to eat such vast quantities that it would damage other aspects of your health.

A study covered in New Scientist reported that people aged 50-69 who consumed drinks enriched with compounds found in cocoa beans for three months performed as well on a memory test as much younger individuals. This is the latest research to suggest that the flavonols in cocoa are responsible for beneficial effects on the brain.

As well as cocoa, flavonols are found in blueberries, green tea and red wine, and previous studies have suggested that mice on a flavonol-rich diet showed improved memory and greater blood flow to parts of the brain. To discover if a diet high in flavonols had a similar effect on humans, researchers persuaded 19 volunteers aged 50-69 to drink 900mg of powdered cocoa flavonols mixed with water or milk daily for three months. Another 18 people drunk a similar beverage containing just 10mg of flavonols.

MRI scans revealed that those on high-dose flavonols had around 20 per cent more blood flowing to part of their hippocampus called the dentate gyrus than at the start of the trial and than those in the low flavonol group. The dentate gyrus region of the brain has previously been linked to age-related memory decline.

Participants’ memories were tested before and after the study. They were shown 41 similar abstract shapes, one after the other, then shown 82 more shapes and asked to identify those from the original batch. Previous work had shown reaction times in this test decrease with age, by about 220 milliseconds for each decade. The high flavonol group reacted to each shape on average 630ms faster than the low dose group. This is equivalent to performing as if they were thirty years younger than the low dosers.

But a few Mars Bars are unlikely to significantly improve your memory. Milk chocolate won’t help, since processing usually removes the key flavonol epicatechin. And to ingest the same amount of epicatechin as the study group, you’d have to consume the equivalent of about seven average-sized bars of dark chocolate a day.

Chocolate manufacturers have cottoned on to the potential health benefits of their product and are considering alternative processing techniques to maximise its flavonol content. Standard processing involves alkalising the cocoa to make it easier to mix and digest, but this process reduces the flavonol content by up to 86 per cent. 

Last updated
The Pharmaceutical Journal, PJ, 24 January 2015, Vol 294, No 7846;294(7846):DOI:10.1211/PJ.2015.20067499

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