A University of Norway team points to coffee diterpenes, cafestol and kahweol levels in raising cholesterol serum levels with its effect very much dependent on brewing method.
"The most important finding was that espresso coffee consumption was significantly associated with increased S-TC (serum total cholesterol)," the authors explain in their study.
"Coffee is the most frequently consumed central stimulant worldwide. Because of the high consumption of coffee, even small health effects can have considerable health consequences.
"Increased knowledge on espresso coffee's association with serum cholesterol will improve the recommendations regarding coffee consumption."
Responding to the study June Davison, Senior Cardiac Nurse at the British Heart Foundation, said: “It’s important to remember that this type of study can only show an association and can’t prove cause and effect.
“We also need to be cautious in drawing firm conclusions, as the researchers didn’t use a standard definition of what an espresso is.
“They also didn’t account for factors such as adding milk or sugar to coffee, which could have an impact on people’s health. More research is needed to look into this further.”
Moderate amount fine
Davison adds that the findings shouldn’t cause concern with a moderate amount of coffee considered fine.
“But be careful if you like to add flavoured syrups or whipped cream, as these can increase your sugar and saturated fat intake,” she adds.
“If you are sensitive to caffeine or you experience heart palpitations (flutters or pounding), it’s best to cut down on the amount you drink.”
Adding further comment to the study findings, Dr Dipender Gill, NIHR Clinical Lecturer in Clinical Pharmacology and Therapeutics, St George’s, University of London, says, “This is an observational study of over 20,000 participants in the Norwegian city of Tromsø.
“While the variation in association between coffee consumption and cholesterol levels observed when stratifying the population by sex and method of brewing coffee are interesting, caution should be taken in interpreting causal effects.
“For example, the observed differences could instead be explained by confounding factors giving rise to spurious associations.
“Specifically, men and individuals with a preference for a certain type of coffee may happen to also have other lifestyle factors that affect their cholesterol levels.
“Generally speaking, it is difficult to infer causation from such observational study designs, and randomised clinical trials are typically required for this.”
Future implications
Commenting on the study’s implications, the team comments that further research about espresso would be ‘beneficial’ to review the new findings.
The preferable study design would be by conducting an RCT, including standardised brewing methods, coffee beans, roasting degree, coffee particle and cup sizes, they add.
“The goal should be to explore whether there is a reliable dose–response curve to diterpene intake and raise in S-TC, and whether there are sex differences.
“Our findings regarding boiled/plunger coffee are the same as in the 1980s, pointing toward results being generalisable.
“This supports previous health recommendations to reduce intake of boiled/plunger coffee because of its capabilities to increase S-TC.”
Source: Open Heart
Published online: doi: 10.1136/openhrt-2021-001946
“Association between espresso coffee and serum total cholesterol: the Tromsø Study 2015–2016.”
Authors: Svatun ÅL, Løchen M, Thelle DS, et al