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 Columbia University, started wondering about the power of chocolate after reading that cocoa was good for you.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. The results - published in the New England Journal of Medicine - were striking.Chocolate consumption and Nobel laureates"When you correlate the two - the chocolate consumption with the number of Nobel prize laureates per capita - there is an incredibly close relationship," he says."This correlation has a 'P value' of 0.0001." says Messerli. This means there is a less than one-in-10,000 probability of getting results like these if no correlation exists.It might not surprise you that 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.