Coffee is perhaps the most popular drink worldwide. It brings people together, it calms nerves in a crisis, it is socially addictive and has a certain elegance, when properly served and consumed. With some people more than one cup of coffee is needed to get started in the morning. It may not be just tiredness though that’s to blame.
Scientists say the need for caffeine is in our DNA, with a particular gene found among those who drink less coffee. It is thought the gene, known as PDSS2, makes it harder for cells to break down caffeine, meaning it stays in the body for longer. As a result, someone with the gene would need to drink less coffee to get the same buzz as someone without it.
The theory comes in a study by scientists at Edinburgh University, who questioned more than 1,200 Italians on their coffee-drinking habits. The men and women also had their DNA read – and those who had the PDSS2 gene were found to drink around a cup of coffee less a day than the others. A second analysis of 1,700 people from the Netherlands confirmed the results, although the effect of genes on the number of cups consumed were slightly lower.
The scientists, who worked with researchers from the Italian coffee company Illy, said the difference could be down to the styles of coffee drunk in the two countries. In Italy people tend to drink smaller cups such as espresso whereas in the Netherlands, the preference is towards larger cups which contain more caffeine overall. Researcher Dr Nicola Pirastu said: ‘The result of our study adds to existing research suggesting that our drive to drink coffee may be imbedded in our genes.’
Caffeine is the world’s favourite stimulant with nearly 90 per cent of adults regularly eating or drinking it in some form. The British alone get through some 70 million cups of coffee a day and 165 million cups of tea. It is thought the number of British people with or without the gene is split fairly evenly, with half having a coffee habit and half easily turning down a second cup. Dr Pirastu suspects he has the-cup-after-cup version and says: ‘I’m one of the few geneticists who haven’t had any DNA read – but I do drink lots of coffee. I can drink it before I go to bed and it has no effect on me.’
The researchers previously found another gene that is carried by people who say they like coffee more. However, these people don’t drink more coffee than others and Dr Pirastu believes that our coffee habit, or the lack of it, has more to do with the effect of caffeine than the way it tastes. He added: ‘This study reinforces the idea that genetics play a very important role in our everyday habits and lifestyles and understanding. This is helping us not only to know how people behave but also why, which will allow us to understand how to act on them.’
The research, detailed in journal Scientific Reports, could shed new light on how coffee seems to ward off certain diseases, including Parkinson’s and some cancers. Plus, some of the chemistry involved in the breakdown of caffeine is involved in the metabolism of medicines. So understanding the process could help doctors understand why some patients respond better to drugs than others.
I find that habit has got a lot to do with how one’s body reacts to caffeine. I am now comfortable drinking coffee at night, whereas this was not the case a few years ago. If anything now, the effect seems to lull me to sleep. How queer is that?