It may be the perfect morning pick-me-up. But a single espresso could be bad for your heart, research suggests.
Just one cup of the caffeine-laden drink cut blood flow to the heart by more than a fifth, a study found. Decaffeinated coffee, in contrast, boosted blood flow.
The researchers said the high amount of caffeine found in a single espresso had 'unfavourable cardiovascular effects'. The popularity of such drinks has risen sharply, in line with the greater variety of coffees on offer. But there have been concerns about the consequences of drinking too many at one time, with the Department of Health advising us not to have more than five a day.
A single espresso contains up to 130milligrammes of caffeine, compared to 75mg in a cup of instant. Filter coffee contains around 120mg per cup. The Italian researchers from the University of Palermo examined the blood flow of 20 adults who drank a single espresso, compared to a decaffeinated alternative.
The caffeinated variety narrowed blood vessels, cutting blood flow to the heart by an average of 22 per cent within an hour, the European Journal of Clinical Nutrition reports. This is because caffeine acts to block a chemical which keeps blood vessels expanded. But when the volunteers drank a decaf espresso, the flow improved slightly. Blood pressure also rose significantly after a normal espresso but not a decaf.