In April 2020, researchers revealed the healthiest way to make a fresh cup of coffee – filtered brew. It’s the first study to examine links between coffee brewing methods and risks of heart attacks and death. Their findings are detailed in the European Journal of Preventive Cardiology of the European Society of Cardiology.
Professor Dag S. Thelle, the author of the study, explained:
Our study provides strong and convincing evidence of a link between coffee brewing methods, heart attacks, and longevity. Unfiltered coffee contains substances that increase blood cholesterol. Using a filter removes these and makes heart attacks and premature death less likely.
Around 30 years ago, Prof. Thelle discovered that drinking coffee was associated with elevated total cholesterol and “bad” LDL cholesterol – so much so that it was highly likely to have harmful consequences for heart health. Experiments pinpointed the culprit substances in coffee that caused these high cholesterol levels and found that they could be removed using a filter. A cup of filtered coffee contains about 30 times less concentration of the lipid-raining substance than unfiltered coffee.
Prof. Thelle said:
We wondered whether this effect on cholesterol would result in more heart attacks and death from heart disease. 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.
For the study, researchers followed 508,747 healthy Norwegian men and women aged 20 to 79 from 1985 to 2003. Volunteers completed a basic questionnaire on the type and amount of coffee consumed. Data was also collected on factors that could influence heart diseases and coffee consumption to account for it in the analysis. Some of these factors include education, smoking, physical activity, weight, height, cholesterol, and blood pressure.
After around 20 years, a total of 46,341 participants died. Of those, 12,621 deaths were caused by cardiovascular disease. Of the cardiovascular deaths, 6,202 were due to a heart attack.
Overall, the researchers found that coffee drinking wasn’t a dangerous habit. Drinking filtered coffee was actually safer than no coffee at all. Compared to no coffee, the filtered brew was associated with a 15% decreased risk of death from any cause during follow-up and a 12% reduced risk of cardiovascular death in men, and a 20% lowered risk of cardiovascular death in women. Meanwhile, the lowest mortality was among those who consumed 1 to 4 cups of filtered coffee per day.
The professor added:
The finding that those drinking the filtered beverage did a little better than those not drinking coffee at all could not be explained by any other variable such as age, gender, or lifestyle habits. So, we think this observation is true.
The study concluded that filtered brew was less risky than unfiltered for death from any cause, deaths from heart attacks, and death due to cardiovascular disease. “Our analysis shows that this was partly because of the cholesterol-increasing effect of unfiltered coffee,” Prof. Thelle pointed out.
Unfiltered coffee didn’t increase death risk compared to refraining from coffee — apart from older men aged 60 and over, where unfiltered brew was associated with increased cardiovascular mortality.
Prof. Thelle explained:
We only had one measurement of coffee consumption, but we know that brewing habits were changing in Norway during the follow-up period. We believe that some women and younger men drinking unfiltered coffee switched to filtered, thereby reducing the strength of the association with cardiovascular mortality, whereas older men were less inclined to change their habits.
Prof. Thelle highlights that these findings are acquired through observational data but advises people who have high cholesterol levels to stay away from an unfiltered brew. Because after all, it’s better to be safe than sorry.
