Does Machine Coffee Actually Raise Cholesterol Levels?

A new study suggests that coffee machines may not adequately filter cholesterol-raising compounds. These findings caught headlines worldwide, claiming that machine coffee may increase cholesterol levels and even raise the risk of a heart attack. However, it is crucial to distinguish between what the study found and what it didn’t.

Research suggests that coffee may offer a wide range of health benefits — from promoting cardiovascular health to protecting against type 2 diabetes.

However, unfiltered coffee contains high levels of cholesterol-raising compounds called diterpenes, kahweol, and cafestol. The latter is the most potent cholesterol-elevating compound known in the human diet.

Too much of one type of cholesterol, called LDL cholesterol, in the blood leads to the formation of deposits in the arterial wall, which can then cause artery narrowing or blockage, raising the risk of heart attack, heart disease, and stroke.

Unfiltered coffee brews, such as Turkish coffee or boiled coffee, contain the highest concentrations of cafestol. Using metal filters, such as in French presses, espresso machines, and moka pots, may lower cafestol concentrations to intermediate levels.

Until recently, only a few studies focused on measuring diterpenes in machine-brewed coffee, which is common in workplaces — as many as 36% of Americans have an in-office coffee station.

A new study published in Nutrition, Metabolism, and Cardiovascular Disease analyzed coffee samples from 14 machines located in four healthcare facilities in Sweden.

They selected the standard setting and size for a brewed coffee cup and took two samples from each machine, 2–3 weeks apart on different weekdays. For comparison, they prepared additional common coffee brews — Scandinavian-style drip-brewed coffee, percolator, French press, and boiled coffee.

High diterpene levels in machine coffee

The study reinforced the findings that the levels of cholesterol-raising compounds in coffee may depend on its brewing method:

• Coffee from brewing machines contained higher diterpene concentrations than paper-filtered coffee but lower than boiled coffee.
• Only one coffee sample from the coffee brewing machine had a cafestol concentration below 100 mg/L.
• Coffee from liquid coffee machines contained cafestol at concentrations of 5.9 mg/L on average and kahweol at 4.8 mg/L.
• Pouring boiled coffee through a polyester/acrylic fabric sock reduced its cafestol levels from 939.2 mg/L to 28.0 mg/L.

The authors speculate that machine coffee may contain higher levels of diterpene because of the lack of a fine filter, which would allow more diterpenes to pass through, bound to coffee particles.

Diterpene levels may also depend on filter cleaning. Paradoxically, cleaning a metal filter could result in greater permeability and more diterpenes in the product.

How does unfiltered coffee impact our health?

According to the study, replacing three cups of brewing machine coffee with paper-filtered coffee five days per week is estimated to reduce the low-density lipoprotein (LDL) cholesterol, also known as the 'bad' cholesterol, by 0.58 mmol/L.

Such reduction in LDL cholesterol would decrease the relative risk of atherosclerotic cardiovascular disease by 13% over five years or 36% over 40 years, the study suggests.

The authors hypothesized that drinking diterpene-high machine coffee equals adding 60 ml full-fat (40%) cream per cup of paper-filtered coffee. Conversely, adding 250 ml of oat milk containing 1 g of cholesterol-lowering beta-glucans to each cup would not fully neutralize the effect of the diterpenes.

Dr Christopher Labos, a cardiologist and an associate with McGill University, says the study authors assume that unfiltered coffee would provoke higher cholesterol levels as a result. However, this relationship isn’t established because they didn’t measure the cholesterol levels of those who drank it.

If you want to prove that something increases the risk of heart attack and stroke, then you have to measure heart attacks and strokes. Just because A leads to B and B leads to C, doesn’t mean that A leads to C in medicine.

Dr Christopher Labos

The link between coffee and cholesterol

There are studies that measure cholesterol levels in coffee drinkers. However, many show an association between coffee and increased cholesterol rather than point to the drink as a cause.

For example, a 2023 study published in Nature Scientific Reports suggests that drinking more than four cups of coffee a day correlates with increased LDL cholesterol levels. However, major cardiovascular diseases like heart failure were not associated with coffee consumption in the study.

According to a 2022 study from Norway, drinking three to five cups of espresso a day is associated with an increased serum total cholesterol by 0.09 mmol/L for women and 0.16 mmol/L for men, compared to those not consuming espresso. The increases in total cholesterol were even more significant in those drinking six or more cups of boiled plunger coffee daily.

However, LDL cholesterol is a more accurate indicator of potential health problems or heart disease risk than total cholesterol, limiting the applicability of these findings.

Labos says cholesterol is complex and largely mediated by genetics, and it’s hard to say whether consuming unfiltered coffee rather than filtered would affect its levels. In general, following a healthy diet is important, but it won’t significantly impact those with genetic causes for high cholesterol.

The more important medical issue here is what we add to coffee. All the flavorings, sugar, cream, and things we add to our coffee dramatically increase the calories and sugar we consume in this beverage. The best type of coffee is black coffee or with as few added flavorings as possible.

Dr Christopher Labos

According to the Centers for Disease Control and Prevention, these are the risk factors for high cholesterol:

• Conditions like type 2 diabetes, obesity, and familial hypercholesterolemia, a disease that causes very high LDL cholesterol levels at a very young age.
• Eating a diet high in saturated and trans fat, such as fatty meats, fried foods, and processed snacks.
• Lack of physical activity may result in weight gain, which can raise cholesterol levels.
• Smoking damages your blood vessels and makes them more likely to be vulnerable to fatty deposit accumulation.
• Age. The risk for high cholesterol increases as we age.
• Sex. Women until around age 55 tend to have lower LDL levels than men.

So, should you quit unfiltered coffee?

The new study suggests that machine coffee contains high levels of cholesterol-raising compounds called diterpenes. However, cholesterol is complex and largely influenced by genetics; therefore, drinking machine-brewed coffee may not necessarily pose health risks.