The scan the researchers used looks for tiny deposits of calcium in the walls of the coronary arteries to provide an early clue that this disease process may be occurring.

None of the employees included in the Korean study had outward signs of heart disease, but more than one in 10 of them were found to have visible calcium deposits on their scans.

The researchers then compared the scan results with the employees' self-reported daily coffee consumption, while taking into account other potential heart risk factors such as smoking, exercise and family history of heart problems.

People who drank a few cups of coffee a day were less likely to have calcium deposits in their coronary arteries than people who drank more than this or no coffee at all.

The study authors say more research is needed to confirm and explain the link.

Coffee contains the stimulant caffeine, as well as numerous other compounds, but it's not clear if these might cause good or harm to the body.

Victoria Taylor of the British Heart Foundation said: "While this study does highlight a potential link between coffee consumption and lower risk of developing clogged arteries, more research is needed to confirm these findings and understand what the reason is for the association.

"We need to take care when generalising these results because it is based on the South Korean population, who have different diet and lifestyle habits to people in the UK."