How Your Coffee Brewing Method May Affect Heart Health

Whether it’s early in the morning or at 3 p.m., a cup of coffee can lift your mood, but it can also affect your heart health.

According to a recent study published in the journal, your favorite cup of tea may contribute to higher cholesterol levels, depending on how it is brewed and filtered. Nutrition, metabolism and cardiovascular diseases.

While the researchers specifically focused on the potential cholesterol-raising effects of coffee brewed by machines commonly found in workplaces in Sweden (and not the United States), the findings remind people in all countries that “the treatment, the preparation of the coffee, makes a difference” in how it affects health, said JoAnn Manson, MD, MPH, DrPH, chief of the division of preventive medicine at Brigham and Women’s Hospital in Boston.

For decades, studies have shown a link between coffee consumption and cholesterol levels. This connection is apparently due to compounds called diterpenes that are found naturally in coffee beans. According to previous research, diterpenes appear to both increase levels of “bad” LDL cholesterol and slightly lower levels of “good” HDL cholesterol.

How coffee is brewed and then filtered, however, has a major impact on what ends up in your cup, research suggests.

Paper filters, like those used in conventional drip coffee machines, appear to remove most diterpenes from the finished brew, while unfiltered coffee (such as boiled coffee) and espresso tend to contain higher levels of these compounds. It is for this reason that the 2023 Nordic Dietary Guidelines specifically warn against excessive consumption of unfiltered coffee.

David Iggman, MD, PhD, lead author of the new study and associate professor of clinical nutrition at Uppsala University in Sweden, wanted to see how the coffee machines often used in Swedish workplaces compared to these other brewing methods. “Swedes drink a lot of coffee, and also during working hours we drink a lot of coffee,” Iggman said. Health.

Iggman and his fellow researchers analyzed the concentrations of two diterpenes – cafestol and kahweol – in coffee brewed by 14 different machines at four Swedish workplaces.

Most of the machines tested in the workplace were “brewing machines,” which typically brew one cup of coffee at a time. But unlike some single-serve coffee makers commonly found in the United States, these machines don’t use coffee pods; instead, they mix coffee and hot water in-house and pass the finished drink through a metal filter before dispensing. (Imagine something that looks a bit like a coffee vending machine.)

For comparison, the researchers also tested diterpene levels in espresso and regular coffee made by various home brewing methods, including boiling, French pressing, percolation, and using a conventional drip coffee machine with paper filters.

Consistent with previous research, the researchers found that boiled coffee contained by far the highest concentrations of diterpenes of the group, followed by espresso; paper-filtered coffee had the lowest levels.

Coffee made in workplace coffee machines, meanwhile, tended to have significantly higher concentrations of diterpenes than all home brewing methods except boiling, the researchers found.

“They vary a lot, but most coffee machines contain fairly high concentrations of these substances,” Iggman said. “It’s not as bad as boiled coffee, but it’s somewhere in between” boiled and filtered coffee.

The study did not test to what extent drinking diterpene-rich office coffee actually affects employee health. It is therefore impossible to draw definitive conclusions on this subject. The research also had other limitations, including a small sample size and limited knowledge about exactly how different machines brewed and filtered coffee.

But, using previous research findings on diterpenes and cholesterol as a guide, Iggman’s team estimated that the difference between drinking a cup of machine coffee or paper-filtered coffee affects cholesterol as much as “having a little cream in each cup,” rather than drinking the beverage black, he said.

Such a difference could conceivably accumulate over an entire career. If someone replaced three cups of coffee machine coffee with the same amount of drip coffee every work day for 40 years, Iggman’s team estimated they could potentially reduce their risk of atherosclerotic cardiovascular disease by up to 36 percent. But again, this is just an estimate; Iggman’s team did not monitor real people in their study.

In general, Manson said, people should limit their consumption of unfiltered coffee or espresso to one serving per day, especially if they have underlying risk factors for cardiovascular disease.

Caffeine lovers who want to consume more than one cup per day should consider switching to filtered coffee for the remainder of their daily dose. “Why take the risk of increasing LDL cholesterol when you can drink filtered coffee?” » asked Manson.

The new study adds to a long-standing debate about how coffee affects health. Older research has raised concerns about health risks potentially associated with coffee consumption, including coronary heart disease. But in recent years, as science has advanced, the pendulum has swung the other way.

Modern studies have linked coffee to a wide range of health benefits, from a lower risk of type 2 diabetes to a longer life. A 2020 review article in the New England Journal of Medicine concluded that “consumption of 3 to 5 standard cups of coffee per day has been consistently associated with a reduced risk of several chronic diseases,” including cardiovascular disease.

Overall, Manson acknowledges, regular coffee consumption appears to be associated with better cardiometabolic health, despite research on diterpenes and cholesterol.

“This should in no way deter people from drinking coffee,” Manson said. “But [it should] perhaps lead them towards filtered coffee rather than unfiltered types of coffee.