The espresso may be the way to experience a stronger aroma and more intense taste from coffee but it could also be the main cause of elevated cholesterol from consuming the drink, according to Norwegian scientists.
The sex of the drinker as well as brewing method, their study also concludes, may be contributing to coffee’s significant downside in raising cholesterol levels – a known risk factor for heart disease.
Drinking espresso was associated with the widest gender difference in cholesterol level; while plunger coffee was associated with the narrowest, their findings published in Open Heart scientific journal show.
Though coffee does not contain cholesterol, its naturally occurring chemicals – diterpenes, cafestol, and kahweol – raise levels of cholesterol in the blood. Most studies indicate moderate amounts (four cups or less daily) can be good for general health, but more than that has been connected to greater risk of death from heart disease.
Brewing method is influential, but it was not clear what impact espresso coffee might have, and in what quantities, so the researchers sought to compare espresso coffee with other brewing methods among adults aged 40 and older.
They drew on data from 21,083 participants (11,074 women; 10,009 men) responding to the latest survey of the Tromsø Study, a long-term population study which began in 1974, involving people living in the Norwegian city.
Participants were asked how many daily cups of coffee they drank – none, one to two, three to five, or six plus – and what brew type they drank including filtered, plunger (cafetiere), espresso from coffee machines, pods or mocha pots, as well as instant.
Blood samples were taken and height and weight measured. Information was also sought on potentially influential factors: diet and lifestyle, including smoking, alcohol intake and physical activity; educational attainment; and whether Type 2 diabetes had been diagnosed.
Women drank an average of just under four cups of coffee every day while men drank an average of nearly five. The association between coffee and “serum total cholesterol” varied, depending on brewing method, with significant sex differences for all brew types bar plunger coffee.
Drinking three to five daily cups of espresso was significantly associated with increased serum total cholesterol, particularly among men. Compared with those who drank none, this consumption pattern was associated with 0.09 millimoles per litre higher serum cholesterol among women versus 0.16 mmol/l higher in men.
A daily tally of six or more cups of plunger coffee was also associated with raised cholesterol: 0.30 mmol/l higher among women versus 0.23 mmol/l higher in men. Getting through six or more cups of filtered coffee every day was associated with 0.11 mmol/l higher cholesterol among women, but not among men – when compared with those not drinking filtered coffee.
While instant coffee was associated with increased cholesterol in both sexes, this did not rise in tandem with number of cups drunk, when compared with those who did not opt for coffee powder/granules.
The researchers noted there was no standardised cup size used in their study; Norwegians tend to drink out of larger espresso cups than Italians do, for example. Different types of espresso – from coffee machines, capsules, or mocha pots – are also likely to contain different levels of the key naturally occurring chemicals. There are as yet no obvious explanations for the gender discrepancy in cholesterol response to coffee drinking.
“Interestingly, coffee contains more than a 1,000 diverse phytochemicals. The intake of each compound also depends on the variety of coffee species, roasting degree, type of brewing method and serving size,” they explain.
Studies show cafestol and kahweol, as well as increasing total cholesterol, have anti-inflammatory effects, protect the liver, and lessen risks of cancer and diabetes.
So coffee contains compounds that may lead to multiple mechanisms operating simultaneously, the researchers underline.
“Coffee is the most frequently consumed central stimulant worldwide. Because of high consumption levels, even small health effects can have considerable health consequences,” they noted.