People who drink three to five cups of coffee each day may have a reduced risk of developing clogged arteries, which can lead to heart attacks, a new study has found.

Research into the effects of coffee on cardiovascular health have been mixed. It was previously thought that coffee consumption increased the risk of heart disease, but a recent analysis of 36 studies on this topic suggested that moderate consumption may reduce the risk.

Furthermore, while consumption has been linked to a reduced risk of type 2 diabetes, it has also been linked to higher blood pressure.

An international team of scientists decided to look into this further by assessing the link between coffee and the presence of coronary artery calcium (CAC) - an early sign of atherosclerosis (hardening of the arteries). Atherosclerosis is a risk factor for heart attack and stroke.

The scientists looked at over 25,000 men and women, with an average age of 41. None of the participants displayed signs of heart disease at the start of the study and all underwent health screening, including a CT scan to test levels of CAC.

The participants' coffee consumption was also assessed and they were divided into groups depending on how much they drank - none, less than one cup a day, one to three cups a day, three to five cups a day and five or more per day.

The average amount of coffee consumed by the participants was just under two cups per day.

The study found that the calcium ratios were 0.77 among people who drank less than one cup per day, and 0.81 for those who drank at least five cups a day.

However among those who drank one to three cups, the calcium ratios fell to 0.66, while among those who drank three to five cups per day, they were just 0.59. In other words, those who consumed three to five cups per day had the lowest prevalence of clogged arteries.

The results stood even when other factors were taken into account, such as age, gender, obesity and high blood pressure.

"Our study adds to a growing body of evidence suggesting that coffee consumption might be inversely associated with cardiovascular disease risk. Further research is warranted to confirm our findings and establish the biological basis of coffee's potential preventive effects on coronary artery disease," the scientists commented.

Details of these findings are published in the journal, Heart.

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