Filtered coffee may be safer than unfiltered for cardiovascular health

A study published in the European Journal of Preventive Cardiology examines the links between coffee brewing methods and risks of heart attacks and death and suggests that filtered coffee is safest.

“Our study provides strong and convincing evidence of a link between coffee brewing methods, heart attacks, and longevity,” said study author Dag S. Thelle of the University of Gothenburg, Sweden, in a press release. “Unfiltered coffee contains substances which increase blood cholesterol. Using a filter removes these and makes heart attacks and premature death less likely.”

Previous research has shown that drinking coffee is linked with raised total cholesterol and LDL cholesterol. Experiments identified the culprit substances in coffee and found that they could be removed using a filter. A cup of unfiltered coffee contains about 30 times the concentration of the lipid-raising substances compared with filtered coffee.

“We wondered whether this effect on cholesterol would result in more heart attacks and death from heart disease,” said Thelle. “But it was unethical to do a trial randomizing people to drink coffee or not. So, we set up a large population study, and several decades later, we are reporting the results.”

Between 1985 and 2003, the study enrolled a representative sample of the Norwegian population: 508,747 healthy men and women aged 20–79. Participants completed a questionnaire on the amount and type of coffee consumed. Data was also collected on variables—such as smoking, education, physical activity, height, weight, blood pressure, and cholesterol—that could influence both coffee consumption and heart diseases.

Participants were followed for an average of 20 years. A total of 46,341 participants died. Of those, 12,621 deaths were due to cardiovascular disease. Of the cardiovascular deaths, 6,202 were caused by a heart attack.

The researchers found that drinking filtered coffee was safer than drinking no coffee at all. Compared with no coffee, filtered brew was linked with a 15% reduced risk of death from any cause during the follow-up period. For death from cardiovascular disease, filtered brew was associated with a 12% decreased risk of death in men and a 20% lowered risk of death in women compared with no coffee. The lowest mortality was among consumers of 1 to 4 cups of filtered coffee per day.

Filtered brew was also less risky than the unfiltered beverage for death from any cause, death due to cardiovascular disease, and deaths from heart attacks. “Our analysis shows that this was partly because of the cholesterol-increasing effect of unfiltered coffee,” said Thelle.