Fresh from her appointment as Director of the Institute of Social and Preventive Medicine, Murielle Bochud takes a true-or-false quiz all about coffee and its main component, caffeine.
The anxious and the coffee-break lovers amongst you need not worry – Murielle Bochud readily admits to drinking four cups a day. The public health expert spent two years in charge of menuCH, Switzerland’s National Nutrition Survey. “Although the average Swiss drinks 250 millilitres of coffee a day, the findings illustrate some very significant differences between our three language regions.”
It comes rather as a surprise: German speakers consume twice as much as their Italian-speaking counterparts in terms of volume, with the French-speaking Swiss somewhere in the middle. Murielle Bochud is less shocked: “The people in German-speaking Switzerland tend to take their coffee long while the Ticinese prefer shorter, Italian-style measures.” A preconception about to be dismantled? It’s not the only one.
A ristretto contains more caffeine than an americano. FALSE
Murielle Bochud: How much caffeine there is in a coffee depends on how it’s prepared. The more water you have passing through a capsule, for instance, the more caffeine you’ll have at the end. So an espresso will contain around 40 milligrams and a regular coffee between 80 and 100. And, by “regular”, I don’t mean the huge cups that the Americans drink.
Caffeine and theine are the same thing. TRUE
However, the main active ingredient in tea is theophylline, a molecule that is slightly different to caffeine but that belongs to the same family, the methylxanthines. Although their chemical composition is different, they have a similar effect. Not many people know that tea – black, green or white – contains theine or caffeine. And you’ll also find it in that other famous black beverage, of course, as well as in cocoa and thus in all chocolate products. Not forgetting carbonated cola drinks, either. It’s virtually impossible to have no caffeine at all in your bloodstream.
Coffee is a family affair. TRUE
When we drink a cup, around 15 different enzymes break the caffeine down into smaller molecules known as metabolites, working more or less quickly depending on our genetic makeup. In other words, how our body metabolises caffeine has a great deal to do with our genes. We really are very different when it comes to dealing with what we eat and drink.
Coffee is bad for you. FALSE
Studies have shown that drinking three to four cups a day over the long term can cut our general risk of death by around ten per cent. We need to be careful, though, as caffeine increases acid secretion in the stomach and softens the muscle that separates it from the oesophagus. Drinking too much therefore increases the likelihood of heartburn, acid reflux and even ulcers. Pregnant women should also avoid drinking too much coffee as it means a higher risk of foetal deformities. The foetus struggles to metabolise the caffeine, which builds up and becomes toxic.
Five coffees a day is too many. FALSE, but…
It’s thought that adults can safely consume around 400 milligrams of caffeine a day, about as much as is in ten espressos or four to five regular coffees. It’s generally believed that you begin to feel the toxic effects – tremors, anxiety, palpitations – after ingesting around a gram, although it’s hard to pinpoint a reliable figure. Be careful, though, as you mustn’t forget the litre of iced tea and the chocolate cake that you’ve also worked your way through. These have got caffeine in them as well. You should also bear in mind that your toxicity threshold will vary considerably depending on your bodyweight, how frequently you consume caffeine – known as habituation – and your metabolism. People can usually tell quite quickly when they’ve exceeded their own personal limit. The maximum daily amount of caffeine recommended for children is 2.5 milligrams per kilo of bodyweight.
Coffee stops you sleeping. TRUE, but…
The drink is a psychostimulant and increases your heart rate. Coffee consumption is also associated with a lower risk of dying in an accident because it keeps the body awake and alert. Now there are those who cannot get to sleep after a coffee. Here too, though, genes are responsible for a significant variation in sensitivity from one person to the next. The faster we metabolise caffeine, the faster its stimulating effect will disappear. This is why some people can have a cup just before bedtime and drop off just like that.
Caffeine can kill. TRUE
Ingesting 10 grams of it can trigger a fatal cardiac arrest. For obvious ethical reasons, however, no experiments have ever been done in the lab to determine the precise fatal dose in humans.
Coffee protects you against type 2 diabetes. TRUE
Drinking coffee is linked to a lower risk of developing type 2 diabetes. Nobody quite knows why this is, although it may not have anything to do with the caffeine since decaf also appears to have a protective effect.
Coffee cuts your risk of stroke. TRUE
People who regularly drink three to four coffees a day have lower blood pressure, which reduces their risk of developing cardiovascular problems such as strokes and heart attacks. In particular, this unexpected finding was revealed by studies that the Institute of Social and Preventive Medicine ran in partnership with other teams from Lausanne University Hospital and various other Swiss hospitals. Participants in the studies who had a higher caffeine level in their urine, i.e. who had drunk more caffeinated drinks, had lower blood pressure. The same was true for people who said they drank four cups of coffee a day compared with those who did not drink any. This beneficial effect was only seen in non-smokers. Cigarettes, even just one a day, will change how your body metabolises caffeine, although we do not know how this correlates with the fact that no protective effect against high blood pressure has been observed in smokers.
Coffee leaves you dehydrated. TRUE
Caffeine stimulates the kidneys to remove sodium from the body via our urine and thus has a diuretic effect. It is probably this property that makes it reduce the risk of high blood pressure, a condition that, after all, is often treated with diuretic drugs. So coffee lovers should make sure they drink lots of water.
Caffeine is a drug. TRUE
Caffeine is added to some anti-migraine medication. It blocks our adenosine receptors, which play a role in feeling pain. Ironically, giving up caffeine can actually give you a headache. It is also used to treat premature babies who stop breathing as it stimulates the respiratory system.
A love of coffee is in your genes. TRUE
Our ability to taste and appreciate certain flavours is influenced by our genetic makeup. People have one of three attitudes towards the bitter taste – there are those who love it, those who hate it and those who could take it or leave it. Coffee, chicory, Brussels sprouts… our passion or our disgust for these bitter substances is determined by our genes. Which is not to say that our environment and our culture have nothing to do with it. Even if they shared identical genes, someone from Japan would not appreciate some foods, such as cheese, in the same way as a Swiss person would.