Workplace coffee might increase your cholesterol levels

Coffee brewed in coffee machines without filters – such as those found in workplaces – can negatively impact health. Compared to coffee from regular paper filter coffee makers, these machines produce coffee with higher levels of cholesterol-raising substances.

In a new study, published in Nutrition, Metabolism and Cardiovascular Diseases, researchers from Uppsala University, in collaboration with Chalmers University of Technology, studied fourteen different coffee machines from various workplaces. The coffee analysed was five common brands of ground coffee, and samples were taken on several occasions.

The study showed that the presence of cholesterol-raising substances was much higher in the machines that do not use filters compared to regular drip-filter coffee makers.

“From this we infer that the filtering process is crucial for the presence of these cholesterol-elevating substances in coffee. Obviously, not all coffee machines manage to filter them out. But the problem varies between different types of coffee machines, and the concentrations also showed large variations over time,” says David Iggman, researcher at Uppsala University, who led the study.

It is previously shown that boiled coffee in a pot contains high levels of the worst of the cholesterol-elevating substances, the diterpenes cafestol and kahweol. Due to this, the latest Nordic dietary recommendations advise to reduce or refrain from drinking boiled coffee. However, a regular drip-filter coffee maker, which uses a paper filter, manages to almost completely filter out these cholesterol-elevating substances. 

Regular consumption can affect cholesterol levels

In this study, the researchers found that the levels of cafestol and kahweol differed greatly between the various machines, but but the levels could also differ at different occasions.

"Few previous studies have examined this many coffee machines, and what is interesting about the results is the high levels of these substances found in coffee from these machines. If you drink coffee regularly at work from a machine that produces high levels of these substances, it could impact your cholesterol levels. Consequently, it could also affect the risk of future heart disease," says Rikard Landberg, Professor at the Division of Food and Nutrition Science, the Department of Life Sciences at Chalmers, where the analyses were conducted.

He continues:

"Coffee machine manufacturers should do more to reduce the levels of these substances in their products."

"Drip-filter coffee, or other well-filtered coffee, is preferable"

The most common type of coffee machine, in the study referred to as brewing machine, produced coffee with the highest concentration of diterpenes. In comparative analyses, the researchers investigated percolator coffee, espresso, French press coffee, boiled coffee, and boiled coffee filtered through a fabric filter. The boiled coffee contained the highest levels of diterpenes per cup. Some espresso samples also contained high levels, but with great variation.

“Most of the coffee samples contained levels that could feasibly affect the levels of LDL cholesterol of people who drank the coffee, as well as their future risk of cardiovascular disease. For people who drink a lot of coffee every day, drip-filter coffee, or other well-filtered coffee, is preferable. To determine the precise effects on LDL cholesterol levels, we would need to conduct a controlled study of subjects who would drink the coffee,” says David Iggman.

More about the study

• The study was published in Nutrition, Metabolism and Cardiovascular Diseases:Cafestol and kahweol concentrations in workplace machine coffee compared with conventional brewing methods
• Two samples were taken from each machine every two to three weeks. The coffee varieties included medium roast and dark roast of five common brands of ground coffee. Most of the machines use ground coffee. One or two grind the beans in the machine, but the researchers don’t think that would have any effect on the levels of diterpenes.
• 14 machines were tested, including 11 brewing machines and 3 liquid-model machines (lower levels, mixed from a coffee concentrate). For comparison, the same analysis was carried out with some other coffee-making methods such as percolator, French press, boiled coffee, and boiled coffee poured through a fabric filter. In addition, four espresso samples were collected in Gothenburg. All the coffee samples were analysed at Chalmers University of Technology.