Does chocolate make you clever?

Eating more chocolate improves a nation's chances of producing Nobel Prize winners - or at least that's what a recent study appears to suggest. But how much chocolate do Nobel laureates eat, and how could any such link be explained?

The study's author, Franz Messerli of Colombia University, started wondering about the power of chocolate after reading that cocoa was good for you, BBC reports.

One paper suggested regular cocoa intake led to improved mental function in elderly patients with mild cognitive impairment, a condition which is often a precursor to dementia, he recalls.

"There is data in rats showing that they live longer and have better cognitive function when they eat chocolate, and even in snails you can show that the snail memory is actually improved," he says.

So Messerli took the number of Nobel Prize winners in a country as an indicator of general national intelligence and compared that with the nation's chocolate consumption.

Switzerland came top of the chocolate-fuelled league of intelligence, having both the highest chocolate consumption per head and also the highest number of Nobel laureates per capita.

Sweden, however, was an anomaly. It had a very high number of Nobel laureates but its people consumed much less chocolate on average.

Messerli has a theory: "The Nobel prize obviously is donated or evaluated in Sweden [apart from the Peace Prize] so I thought that the Swedes might have a slightly patriotic bias.

"Or the other option is that the Swedes are excessively sensitive and only small amounts stimulate greatly their intelligence, so that might be the reason that they have so many Nobel Prize laureates."