Over the years, coffee has been celebrated for everything from extending life span to lowering Type 2 diabetes risk, but a new study suggests that the way you prepare your daily cup of joe might be just as crucial as what you’re drinking in the first place.
An observational study published in the European Journal of Preventive Cardiology in April took a closer look at the coffee habits of 508,747 men and women between the ages of 20 and 79 and found that drinking unfiltered coffee was associated with higher rates of heart disease and death than drinking filtered coffee. The Norwegian study analyzed data gathered over 18 years from 1985-2003 and relied on self-reported cases of coffee consumption and cardiovascular disease.
Accroding to Aage Tverdal, a senior researcher at the Norwegian Institute of Public Health and lead author of the paper, he and his co-authors wanted to study the impact of different coffee brewing methods on heart health because it could be one of the many factors contributing to why some people who drink coffee see benefits and others do not.
Since the 1980s, scientists have understood that drinking coffee can impact cholesterol. Research has shown that compounds called diterpenes in unfiltered coffee, specifically cafestol and kahweol (two kinds of coffee oils), can raise LDL or bad cholesterol levels. With this in mind, Tverdal told TODAY Health in an email that his team posed the question, “Does the use of (a) filter have an effect on (cardiovascular disease) mortality?”
The study focused specifically on drip coffee brewed with paper filters, the traditional preparation in Norway. Another popular form of filtered coffee is the pour-over method. Unfiltered coffee was defined as a drink made from “ground coffee beans (that) simmer in close-to-boiling water.” This type of brewing method can include French press, Greek style or Turkish style brews.
Over half of participants (59%) preferred filtered coffee, 20% drank unfiltered coffee, 9% consumed both brews and 12% drank no coffee at all. Men who drank unfiltered coffee “had a higher mortality than the men not drinking coffee” and women who drank all three types of brews had “significantly lower” heart disease mortality. “Among coffee consumers, the reference group of 1-4 cups per day of ﬁltered brew had the lowest mortality and 9 cups per day of unﬁltered brew had the highest mortality.”
These results were not surprising to the researchers — or to Dr. Andrew Freeman, the director for cardiovascular prevention and wellness at National Jewish Health in Denver and a member of the American College of Cardiology’s Prevention of Cardiovascular Disease Section Leadership Council, who was not involved with the study.
“Filtered coffee seems to be quite healthful,” Freeman told TODAY. "Depending on what study you look at, anywhere between 2 and 6 cups a day actually reduces cardiovascular events." But it doesn’t mean that you should start drinking coffee if the beverage isn’t already part of your regular diet. “It’s important that if one is going to drink coffee that they probably should drink it habitually. If you drink coffee sporadically, meaning not every day, that can actually raise blood pressure.”
Freeman also cautions, “If people are sensitive, meaning they have blood pressure or arrhythmia or atrial fibrillation or other things like that, I recommend they avoid coffee altogether.”
Registered dietitian Whitney Linsenmeyer, a spokesperson for the Academy of Nutrition and Dietetics and an assistant professor of nutrition at Saint Louis University, agrees that coffee can be part of a heart-healthy diet. “I rely on the 2015-2020 Dietary Guidelines for Americans, which are rather encouraging for regular coffee drinkers in that they indicate that moderate coffee consumption (three to five 8-ounce cups/day or servings providing up to 400 mg/day of caffeine) can be incorporated into healthy eating patterns,” she explained in an email to TODAY.
“Generally the American Heart Association agrees that moderate coffee consumption does not seem to be harmful, and may even lower the risk of heart disease,” she continued.
The Norwegian study concluded that filtered coffee was best. Freeman echoed this, suggesting that coffee drinkers keep their brews simple and choose filtered, black coffee — without sugars and creamers.
“The two most important factors to keep in mind," says Linsenmeyer, "are total caffeine intake and any additions, such as milk, cream or sugar. These will contribute to your total calorie and added sugar intake, but these too can be incorporated into a balanced diet. Personally, my day starts with a whole milk latte (re: unfiltered coffee!), and that is certainly not going to change.”