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Chocolate medalsThere has been a recent news story about the curious fact that countries where chocolate consumption is high tend to produce more Nobel prizewinners. The correlation was quite stark. Are there any reasons why this could be the case, including statistical anomalies not directly related to chocolate? Ironically, my country, Sweden, home of the Nobels, was one of the very few that didn’t fit the pattern.

n Rich Western countries tend to have a history of academic success, as shown by the number of Nobel prizewinners they produce. They also have a high consumption of foods that are considered to be less healthy, including chocolate. Sweden, as your correspondent states, does not exhibit this association.

By examining international obesity league tables, we can see

that Sweden ranks fairly low for a Western nation, suggesting that it has taken on board health messages regarding diet. Other rich countries with an academic pedigree, such as the UK, the US, Canada and Australia, have not.

In the 1980s, Sweden reacted to high cardiovascular disease mortality rates by introducing an official food-labelling system and

a programme of health screening and counselling. This programme was reported by participants to be influential in supporting lifestyle change. The food labelling brought about a significant increase in the sales of low-fat products. It is a reasonable hypothesis that the actions of the Swedish government have caused the non-correlation between chocolate consumption and the number of Swedish Nobel prizewinners. The message should be obvious to us all.

An alternative hypothesis could be that non-Swedish academics consume massive amounts of chocolate.David MuirScience departmentPortobello High SchoolEdinburgh, UK

n Correlation need not imply causation. However, correlated independent effects commonly have related causes, and the failure of some countries to fit the pattern suggests that this correlation is an example. Although I’m not a true chocoholic, I would love there to be a causative connection, but my own suspicion is that many of the achievements awarded Nobel prizes were nurtured in environments that rarely occur in nations lacking luxuries such as good nutrition, good health, good education, hubris, enterprise and being able to afford lots of good chocolate. As Lady Randolph Churchill said: “We owe something to extravagance,

for thrift and adventure seldom go hand in hand.” Jon RichfieldSomerset West, South Africa

n It cannot be true that the amount of chocolate consumed increases your chances of winning, because women have taken just 5 per cent of the Nobel prizes awarded. One need not accept the

sweeping generalisation from the media machine, which would have us believe that women love chocolate more than men do, but it is probably fair to say that women and men enjoy chocolate in roughly equal numbers. Richard FuLondon, UK

This week’s questionsMeTallergyYou recently ran a question about using silver in clothing as an antimicrobial. I used to be a consultant assisting a company that refined precious metals. One of its employees told me that his eyeballs were jet black because he had absorbed so much silver into his body. He was otherwise healthy. Can any reader confirm that silver can do this? If so, is it harmful?F. G. GrisleyBarry, Glamorganshire, UK

TriCk phoTographyTelevision coverage of football matches can show adverts projected onto pitchside hoardings that can’t be seen by spectators in the stadium. These fans just see the normal static adverts painted on the boards surrounding the pitch. How does this technology work? Specifically, when the camera moves to follow the players how do the adverts seem to stay in the right place?Colin DaleyMilton Keynes, Buckinghamshire, UK

STiCk iN The MUDI know how green leaves photosynthesise, and The Last Word has explained how red leaves photosynthesise. I have an air plant (Tillandsia) with long, thin spiky leaves that appear yellow-brown, dry and, to all appearances, dead. How do these photosynthesise? I don’t water it, but it is alive because every so often a new leaf shoot appears.Caroline DaveyBuckingham, UK

Big BlUeWhy do blue whales need to be so big when they only eat plankton?Peter Hammond (aged 7)Toronto, Ontario, Canada

The NoSe kNowSWhy do heavy drinkers of alcohol develop bulbous noses? Does this occur in all cases of heavy drinking?Peter Lloyd-JacksonBirmingham, Alabama, US

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