Seoul, March 3 (IANS): People consuming three to five cups of coffee a day have the lowest risk of clogged arteries and heart attacks, says new research.

An international team of researchers led by the Kangbuk Samsung Hospital, Seoul, South Korea, set out to examine the association between coffee consumption and the presence of coronary artery calcium (CAC) which is an early indicator of coronary atherosclerosis (when arteries become clogged).

It can cause the arteries to harden and narrow, leading to blood clots which can trigger a heart attack or a stroke.

They studied a group of 25,138 men and women - average age 41 - who had no signs of heart disease.

The researchers estimated the CAC score ratios associated with different levels of coffee consumption compared with no coffee consumption.

They categorised coffee consumption as none, less than one cup a day, one to three cups a day, three to five per day and at least five or more per day.

The calcium ratios were 0.77 for people who had less than one cup per day, 0.66 for those having one to three cups every day, 0.59 for those consuming three to five cups per day, and 0.81 for people having at least five cups or more every day compared with non-coffee drinkers.

The researchers found the prevalence of detectable CAC was 13.4 percent among the whole group of people and the average consumption of coffee was 1.8 cups per day.

Possible explanations for the findings, said the researchers, were that chronic coffee consumption had a possible link to reduced risk of Type 2 diabetes, a strong risk factor for atherosclerosis.

“Coffee consumption might be inversely associated with CVD (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 authors concluded.