New research demonstrated that coffee from workplace brewing machines could contain higher concentrations of cholesterol-raising compounds compared with paper-filtered coffee, potentially representing an overlooked cardiovascular risk factor for regular consumers.

In the study, published in Nutrition, Metabolism & Cardiovascular Diseases, Swedish investigators from Uppsala University and the Chalmers University of Technology measured concentrations of the cholesterol-raising diterpenes cafestol and kahweol in various coffee brewing methods, with particular attention to workplace machine coffee that many employees consumed daily.

“Most coffees from workplace brewing machines contain higher diterpene concentrations than paper-filtered coffee but lower than unfiltered coffee. Intake of insufficiently filtered coffee during working hours could be an overlooked factor for cardiovascular health due to its effect on plasma cholesterol concentrations,” the study authors emphasized.

The investigators analyzed coffee samples from 14 machines at Swedish health care facilities and compared them with home-prepared brews.

The median cafestol and kahweol concentrations were:

• Brewing machines (n = 11): 175.7 mg/L (range = 24.4–444.0) and 141.8 mg/L (range = 17.8–434.2), respectively
• Liquid-model machines (n = 3): 8.3 mg/L (range = 2.4–343.4) and 6.7 mg/L (range = 1.8–288.2)
• Home-brewed, paper-filtered coffees (n = 5): 11.5 mg/L (range = 4.2–23.8) and 8.2 mg/L (range = 2.8–19.0).

For comparison, boiled coffee contained 939.2 mg/L of cafestol and 677.9 mg/L of kahweol. However, filtering boiled coffee through a polyester/acrylic fabric reduced concentrations to 28.0 mg/L and 21.2 mg/L, respectively.

Other brewing methods contained intermediate diterpene levels. Percolator and French press coffee yielded 91.2 mg/L and 86.8 mg/L of cafestol, and 69.2 mg/L and 68.7 mg/L of kahweol, respectively. Some espresso samples exhibited exceptionally high concentrations, with cafestol levels up to 2446.7 mg/L.

Based on established dose-response relationships, the investigators estimated that replacing 3 cups of brewing machine coffee with paper-filtered coffee 5 days per week could reduce low-density lipoprotein (LDL) cholesterol by 0.58 mmol/L.

“One review has estimated LDL cholesterol to increase 0.0104 mmol/L per mg of cafestol and 0.0016 mmol/L per mg of kahweol daily ingested,” the study authors noted, citing prior literature.

This estimated reduction in LDL cholesterol would correspond to a 13% decreased relative risk of atherosclerotic cardiovascular disease (ASCVD) over 5 years and a 36% reduction over a 40-year working life, based on previous models of cholesterol reduction and cardiovascular outcomes.

The investigators employed liquid chromatography–tandem mass spectrometry for precise measurement. Quality control procedures demonstrated high reproducibility, with coefficients of variation ranging from 0.9% to 6.8% for both compounds across a range of concentrations.

Substantial variability in diterpene content was observed between samples collected from the same machine 2 to 3 weeks apart. The mean differences were 103.3 mg/L (58%) for cafestol and 88.3 mg/L (65%) for kahweol.

The investigators hypothesized that elevated diterpene levels in brewing machine coffee likely resulted from the absence of a fine filter, allowing more diterpenes to pass through bound to coffee particles. They further suggested that cleaning schedules might paradoxically increase filter permeability, thereby raising diterpene content.

Limitations of the study included its relatively small sample size and lack of technical details about the machines used—especially with regard to filter design, water temperature and pressure, and coffee grind and roast characteristics.

The investigators noted that the associations between machine coffee intake and increased plasma cholesterol or ASCVD risk remained to be directly confirmed in randomized controlled trials and prospective observational studies.

They recommended further investigations into how different machine parameters could influence diterpene content, along with short-term crossover trials to measure direct effects on plasma lipid levels.

“Based on the concentrations of cafestol and kahweol in investigated machine coffees, thoroughly filtered coffee seems like the preferable choice for cardiovascular health. Accordingly, filtered coffee should be preferred, also in workplace settings,” the study authors concluded.

Disclosures were not made available in the study.