The second study, published in the journal Clinical Nutrition, analysed the genetic data of 362,571 participants to explore the link between heavy coffee consumption and the fat, including “bad” LDL cholesterol, found in our blood.
Coffee beans contain a “very potent” cholesterol-elevating compound called cafestol and too much fat in the blood heightens the risk of CVD.
The researchers, from the Australian Centre for Precision Health at the University of South Australia, found that the more coffee people reported drinking the higher their levels of blood fat.
Based on these high levels, the “heavy drinkers” – those drinking six or more cups of coffee a day – increased their risk of CVD by 23 per cent.
CVD is the leading cause of death in Australia so it makes sense that researchers want to better understand how we can mitigate the risks. Australians also love their coffee.
Three quarters drink at least one cup of coffee per day, and 28 per cent of those have three or more cups per day.
Professor Elina Hyppönen, the lead researcher in the second study, acknowledges that most Australians don’t drink six cups of coffee a day. Hyppönen, who was enjoying a cup of coffee when our phone interview took place, explained that individuals process coffee differently but those with high cholesterol or concerns about their heart health should go easy and stick with coffee types that do not contain cafestal.
Unfiltered coffee, including Turkish, boiled and plunger coffee, contains the highest amounts of cafestol; espresso contains slightly less while filtered coffee, including instant coffee and coffee using filter papers (which “catch” the cafestols), contain hardly any.
Dr Alan Barclay is an accredited practising dietitian and researcher at the University of Sydney, who was not involved in either study. He says that the issue with the first study is that it is observational.
“It’s not a particularly strong method for proving health effects, because what else is going on? What else are they having it with?” he asks.
He says studies on coffee often suffer the same problem as studies on eggs.
“A meta-analysis recently showed people who consumed eggs in North America had an increased risk of diabetes but those that ate them in other parts of the world didn’t and though that might sound a bit weird it probably comes down to the way the Americans consume them most likely – with bacon probably.”
And although the cafestol fats in certain types of coffee may contribute to higher cholesterol in some people, it may also depend what they are consuming their coffee with, Barclay says.
“It’s going to be your overall diet that really matters. If you have a diet that’s fairly high in unsaturated fats – in mono and polyunsaturated fats and relatively high in dietary fibre, in particular the more viscous ones, the ones you find in oats and barley and fruit – it tends to bind cholesterol in the gut [this prevents the cholesterol from entering the bloodstream], that’s going to have an impact as well.”
So to drink or not to drink? That is the question.
If you enjoy it, drink it, but not too much.
The first study’s authors stopped short of recommending people up their consumption of coffee to lower their risk of heart failure and Barclay says that “as with all things” the dose makes the poison.
“A moderate intake is generally safe. People just need to be sensible about drinking a moderate amount of good quality coffee in the context of a healthy diet and don’t worry about it.”
For the most part Hyppönen agrees, saying our bodies are often our best guide.
“Once you drink too much you start getting every unpleasant sensations – you get palpitations and your heart rate goes up and you just don’t feel good. That’s a clear sign you are having too much,” she says.
“The important thing is to listen to your body and stick to the limit that feels good for you. Usually the good message in nutrition and perhaps elsewhere in life is to stick to moderation.
“For people who do have concerns about their cholesterol or their heart health in general it may be prudent to pay attention to the type of coffee that they drink.”
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Sarah Berry is a lifestyle and health writer at The Sydney Morning Herald and The Age.