Your morning coffee could be causing a cholesterol spike – but it's all down to how you make it

Telegraph

25-04-2025

Coffee lovers rejoice: your beverage of choice is now being recognised as a health-promoting staple. Old-fashioned theories that coffee raised the risk of coronary heart disease have been debunked: a 2022 study by the European Journal of Preventive Cardiology found that people who sipped two to three cups a day had a lower risk of cardiovascular disease and early death than those who didn't.
Of course, studies like the above need to be read in context. They can't always prove 'cause and effect' as there may be something else about the coffee drinkers' lifestyle that keeps them healthy – perhaps they have better diets overall than non-coffee drinkers. It's encouraging for those who enjoy a flat white though.
But now new research shows that it's not just whether you drink coffee that matters to your health, the way you brew it can have a significant effect on your cholesterol levels and heart health too. The study, released in March from Uppsala University in Sweden and published in the journal Nutrition, Metabolism and Cardiovascular Diseases found that some methods of coffee preparation can have the unwelcome outcome of raising your low-density lipoprotein cholesterol (aka LDL or 'bad' cholesterol). The researchers suggested a hierarchy of cholesterol-friendly ways of coffee preparation. At the 'bad' end lies Turkish-style boiled and some office-machine coffees, with filtered coffee coming out as the best option, and other methods somewhere in between.
Why does coffee spike your cholesterol?
Coffee does not in itself contain cholesterol. But the beans contain natural oils which include two chemical compounds called cafestol and kahweol and it's the mechanism of these on the body that can raise cholesterol levels.
David Iggman is a GP, and an associate professor in clinical nutrition at Uppsala University. 'Cafestol and kahweol are lipid molecules called diterpines,' he says. 'They are unique to coffee beans and have similar properties to cholesterol.'
Diterpenes interfere with the body's natural processes of cholesterol breakdown and transport, potentially leading to an increase in total cholesterol, LDL cholesterol, and triglycerides, while also decreasing the 'healthy' HDL cholesterol. Scientists still don't understand exactly why this happens, but have known since the late 1990s that 'boiled' coffee, made on the stove, is particularly high in diterpenes.
'Many types of office hot drinks machines brew their coffee in a similar way to the boiled variety,' explains Iggman. 'In Swedish workplaces, there are almost mandatory breaks around these machines, and so we decided to test them.'
How the way you prepare your coffee impacts your cholesterol
The Uppsala team studied the offerings from a number of coffee machines. They discovered that, depending on whether the coffee was brewed by the machines, or filtered by them, the levels of diterpenes were significantly raised.
'Six cups of boiled coffee a day will raise your cholesterol by around 10 per cent,' says Iggman.
At the other end of the scale, coffee which is made with a paper filter turned out to be the healthiest choice. 'For people who drink a lot of coffee every day, making it this way manages to almost completely filter out these cholesterol-elevating substances,' advises Dr Iggman. Those who have recently invested in an Aeropress can feel smug.
Coffee from a cafetière comes somewhere between boiled and filtered coffee, as do the cups you buy from high street chains such as Pret or Starbucks. 'Some espresso samples also contained high levels of diterpenes, but there was great variation,' says Iggman. 'We didn't look at instant coffee in our study, but previous studies have shown it has a similar profile to filter coffee.'
According to Iggman, you can get an idea how healthy your homemade coffee is, just by looking at it. 'If your drink appears cloudy, it probably hasn't been properly filtered,' he says.
Does coffee have any heart health benefits?
Several other studies have pointed to coffee's heart-health-promoting characteristics. According to the 2023 Coffee and Real-time Atrial and Ventricular Ectopy trial (also known by the snappy acronym CRAVE), drinking coffee might increase the amount of exercise you do.
The study, which was published in The New England Journal of Medicine, found that on the days people drank coffee, they took an average of 1,000 extra steps per day.
'Every additional coffee drink was associated with 587 more steps per day,' the researchers say. 'This magnitude of step count differences has been associated with improved health outcomes, including reduced mortality. Presumably, the caffeine helped with the psychological motivation to exercise or enhanced physical performance in a way that made such activity easier or more enjoyable.'
The downside was that participants slept 36 fewer minutes per night, on average.
What's the best time of day to drink coffee for heart health?
A study published in the European Heart Journal in February this year found that people who drank coffee in the morning had a lower risk of dying from cardiovascular disease and had a lower mortality risk than all-day coffee consumers.
'A possible explanation is that consuming coffee in the afternoon or evening may disrupt circadian rhythms (our bodies 24-hour cycle of physical, mental and behavioural changes) and levels of hormones such as melatonin,' says Dr Lu Qi, the lead researcher and director of Tulane University Obesity Research Centre.
'This, in turn, leads to changes in cardiovascular risk factors such as inflammation and blood pressure.'
Like the 2022 paper from the European Journal of Preventive Cardiology, these latter two studies were 'observational', in that other factors could have affected the results. Dr Qi suggests that further research is needed to work out exactly why morning coffee is healthier.
How to master a heart-healthy coffee habit
Choose filter coffee and avoid office-machine coffees
The study from Uppsala University in Sweden and published in the journal Nutrition, Metabolism and Cardiovascular Diseases found filtered coffee to be most cholesterol-friendly while suggesting Turkish-style boiled coffee and some office-machine coffees are to be avoided.
Aim for two to four cups
'A moderate amount of coffee or tea, say four cups a day, should be fine for most people,' says Victoria Taylor of the British Heart Foundation. 'Research shows that this level of caffeine intake shouldn't be detrimental to your heart health.' Any more than this might increase heart rate and blood pressure in some people, leading to palpitations.
Drink it black
Scientists also concur that it's not just the brewing of the beans that affects your heart health. 'Adding sugar to your coffee or tea, or drinking lots of milky coffees, is more likely to be a problem than the caffeine because the calories can add up, causing you to gain weight,' explains Taylor. Ditto the white chocolate mochas and the caramel macchiato, as well as that slice of carrot cake you just happen to have on the side.