There’s more evidence that coffee can be downright good for you.
A study of South Korean coffee consumers found moderate drinkers are less likely to have signs of blocked arteries than people who drank no coffee — or those who drank five or more cups a day.
People who drank three to just under five cups a day of filtered coffee were the least likely to have evidence of heart disease, Dr. Yoosoo Chang of Kangbuk Samsung Hospital in Seoul and colleagues found.
It’s one more piece of data in a growing body of studies that suggest a few cups of coffee a day can be healthful. Federal advisers have recognized this, suggesting that new federal guidelines on what to eat include an okay on moderate coffee intake.
Chang and colleagues used information from an ongoing study of about 30,000 South Korean men and women whose health is being watched in detail. They looked closely at about 25,000 of them who had no evidence of heart disease and who were, on average, 41 years old.
They all had scans that look for calcium in the arteries. The calcium indicates a plaque is growing in the artery. These plaques can block blood flow and they can also break off and cause a heart attack or stroke.
They divided the men and women into four groups: those who drank less than one cup of coffee a day; those who had one to three cups a day; three to five per day and those drinking five or more cups a day.
Overall, 13 percent had detectable calcium and, on average, people drank about two cups a day of coffee.
People who drank the most and the least coffee had the most calcium buildup. People who drank one to five cups a day had less, the team reported in the journal Heart.
There are many possible explanations for why coffee drinkers might be healthier. “Coffee consumption has been associated with improved insulin sensitivity, reduced low density lipoprotein cholesterol (LDL-C) oxidation, and reduced risk of type 2 diabetes,” the researchers wrote.
When a chemical reaction causes LDL, the bad cholesterol, to oxidize, it becomes the basis for the sticky artery blockages.
Coffee may help make blood vessels healthier, also — something referred to medically as improved endothelial function.
But coffee can also raise blood pressure, and some studies show people who drink unfiltered coffee like espresso may have higher cholesterol. That may be because of oils called terpenes, which include cafestol and kahweol. Paper filters soak them up.
It also wasn’t clear why drinking five or more cups a day might be bad. But the researchers said heavy coffee drinking went with other heart disease risk factors.
“Individuals in the highest categories of coffee consumption were more likely to be older, men, and current smokers and to have higher education, less frequent vigorous-intensity physical activity, obesity, and hypercholesterolemia (high cholesterol) and to have a lower proportion of hypertension (high blood pressure),” they wrote.
They also ate more food overall, especially meat, and ate fewer vegetables.
People often worry that the caffeine in coffee could be bad for your health. That caffeine is highly addictive, but there's little evidence showing the amount a moderate drinker gets is harmful.
This article was originally published Mar. 2, 2015 at 7:05 p.m. ET.