Coffees served in Glasgow have more caffeine than brews tested in Italyand Spain, according to a small study of drinks on sale in cafes.

In one Glasgow cafe, there was 212mg of caffeine in an espresso – above the recommended daily limit for pregnant women, which is 200mg in the UK. The study’s authors say the variation in caffeine levels means information should be made readily available to consumers on bean variety and caffeine content and that there should be guidelines forcoffee-making.

For the study, published in the Royal Society of Chemistry-produced journal Food and Function, researchers from the University of Glasgow, the University of Parma in Italy and the University of Navarra, in Pamplona, Spain, tested coffees in 26 city centre coffee shops in Glasgow, Parma and Pamplona. They took four samples from each outlet and then calculated the mean amount of caffeine. They found the caffeine content in the Scottish espressos ranged from 72mg in Starbucks to 212mg in an independent cafe, compared with 73mg to 135mg in Italian espressos and 97mg to 127mg in Spanish ones. Some of the differences were down to serving size. Tests were also carried out on cappuccinos at five Glasgow outlets and they were found to have between 101mg and 275mg of caffeine.

The authors said the increased blending of arabica with robusta beans, which have double the caffeine content of arabica, will lead to higher caffeine content in commercial coffee.

University of Glasgow researchers have previously warned about the amount of caffeine in coffees served in the city. The researchers said the levels were not as high as in an earlier study, perhaps because of “the considerable local publicity over extreme caffeine contents after this [previous] publication”.

There was also variation in the amount of caffeine in instant coffees prepared by researchers using 2g in 125ml of water, from 48mg of caffeine in three Nescafé blends to 88mg in Fortaleza Natural. The NHS advises that the limit for pregnant women is equivalent to two mugs of instant coffee.

The authors conclude: “It is evident that regular coffee drinkers, whether they favour an espresso, cappuccino or an instant beverage, can, without realising it, have a caffeine intake well in excess of 200mg per day.

“In these circumstances, it is evident that providing consumers with readily available information on bean variety and caffeine levels, including labelling of instant coffees, and providing guidelines for coffee-making, would benefit consumers and coffee shops alike.”