The average Briton eats more than 10kg of chocolate a year, nearly 3kg more than the average Belgian, who at least has the excuse of temptation from high-quality confection. So it’s encouraging that research, albeit partly funded by Mars, has found that chocolate is good for the brain.

The study, published in Nature Neuroscience, looked at the effects of high-cocoa versus low-cocoa drinks in 37 people aged between 50 and 70. Cocoa contains flavanol, an antioxidant found in plants.

The randomised control trial tested cognition and looked at brain scans of the participants. The researchers found that people given cocoa with high levels of flavanols scored better on cognitive tests and had more activity (better blood flow) in the dentate gyrus – the brain area associated with memory. Senior author Dr Scott A Small told the New York Times: “On average, the improvement of high-flavanol drinkers meant they performed like people two to three decades younger on the study’s memory task.”

So, forget obesity – who wouldn’t want to devour enough chocolate to keep their brain working as well as it did 20 years ago?

The solution

The study in Nature Neuroscience was small and didn’t test anyone under the age of 50. Although the higher flavanol group did the cognitive tests faster, they didn’t do better on recall questions that focused on their ability to remember if they had seen an image before. Part of the study examined the effects of exercise on cognitive function and found no effect – contradicting previous research. Plus, you’d need to eat lots of commercial chocolate to get the right flavanol levels.

There is, however, other evidence that chocolate has health benefits. A review (admittedly not a systematic one, which would be more reliable, since it would tell you how the studies included in the review were chosen) of cocoa and cardiovascular health in the journal Circulation suggests that epicatechin, a specific flavanol, may have antioxidant and anti-inflammatory effects that protect the inner walls of blood vessels from atherosclerosis. So chocolate may be due some credit for widening blood vessels, keeping their lining smooth and increasing blood flow.

Chocolate has also been found, in some studies, to reduce blood pressure and the risk of stroke. Dark chocolate, with 70% cocoa solids, is the healthiest, since it has little sugar, its fat comes from cocoa butter and it contains iron and magnesium. However, since commercial chocolate contains about 500 calories for every 100g, it’s worth rationing it.

If you’re thinking healthy, there are – sadly – plenty of better options out there.