Full of beans

For many of us, it’s rare for a day to start without a cup of coffee. According to the British Coffee Association, approximately two billion cups are consumed worldwide each day, making coffee the world’s most popular beverage – and caffeine the most widely used psychoactive compound.

Given its ubiquity, it can be hard to determine what our coffee consumption means for our health. We know that it keeps us alert and tides us through a gruelling workday. We also know that, past a certain level of consumption, the disadvantages can seem to outweigh the advantages. Many of us are familiar with the jitters that accompany that third espresso, or the insomnia that follows a coffee chugged late at night.

What’s less clear is how coffee affects our bodies over the long-term, and why this might be. The European Food Safety Authority stresses that moderate caffeine consumption (up to five cups of coffee a day) can be enjoyed as part of a healthy balanced diet. It’s a message echoed by health organisations the world over.

The risks versus the benefits

That said, stating that a foodstuff can be enjoyed safely isn’t the same as saying that it’s healthy. In fact, the health impacts of coffee (for better or for worse) have long been subject to scientific scrutiny.

Most early studies (before 1990) were negative in their conclusions – they found that coffee drinkers tended to have worse heart health than their peers. However, these studies often didn’t account for confounding variables, like the fact that heavy coffee drinkers were more likely to be smokers too.

These days the tide seems to be turning. Barely a week goes by without a new study linking our favourite beverage to cardiovascular benefits, decreased Alzheimer’s risk or even a higher life expectancy. Case in point? A 2017 review paper, which looked at a staggering 201 meta-analyses, found that ‘coffee consumption was more often associated with benefit than harm for a range of health outcomes’.

“Recently we’ve seen more and more research being conducted around the potential health benefits of coffee, with most research concluding that consuming a moderate amount of coffee can have positive health impacts,” says Thomas De-Garnham, founder of British coffee brand Fireheart Coffee. “We at Fireheart welcome this kind of research and would like to see studies continue into the future.”

Fireheart isn’t the only coffee brand to take an interest in the research. Take the Institute for Scientific Information on Coffee (ISIC), a not-for-profit organisation comprising six major brands (illycaffe, Jacobs Douwe Egberts, Lavazza, Nestle, Paulig and Tchibo). The institute says it is ‘devoted to the study and disclosure of science related to coffee and health’.

According to ISIC’s most recent report, people are becoming increasingly curious about this topic. The report claims that Google searches for “health benefits of drinking coffee” surged by 650% between February 2021 and February 2022.

Dr JW Langer, a spokesperson for ISIC, said: “A new generation of people are now beginning to appreciate the complex nutritional components of their trusty morning drink, and the additional beneficial health effects that regular, moderate consumption may offer as part of a balanced diet. A fact that is supported by an increasing volume of scientific research.”

Beans, beans, good for the heart?

A good place to start might be a study published in February by researchers at Queen Mary University of London (QMUL) and Budapest Semmelweis University. This study, the largest of its kind, used data from nearly half a million participants in the UK Biobank. It found a clear link between moderate coffee consumption and better heart health.

The participants were divided into three groups: non-coffee drinkers, light-to-moderate coffee drinkers (up to three cups a day), and heavy coffee drinkers. Their cardiovascular health was tracked for an average of 11 years. Compared with the non-coffee drinkers, the middle group had a 12% lower risk of overall mortality, a 17% lower risk of death from cardiovascular diseases, and a 21% lower risk of stroke.

As well as looking at health outcomes, the study also included cardiac magnetic resonance imaging from some 32,000 people. This gave the researchers an inside look at how coffee might affect the cardiovascular system.

“In comparison to zero coffee intake, light-moderate and high coffee consumption were associated with favourable cardiovascular traits, both in terms of cardiac and arterial health,” says study author Professor Steffen Petersen, of the William Harvey Research Institute at QMUL. “Results from our study and others all seem to suggest that the health benefits of moderated ground coffee consumption outweigh its potential risks.” 

He stresses that these benefits are likely to tail off at higher levels of coffee consumption. In 2021, a different UK Biobank study concluded that long-term heavy consumption might actually increase people’s risk of cardiovascular disease. On top of that, this study was mainly concerned with health impacts at a population level. It didn’t examine why coffee might improve heart health, or even establish a causal connection.

“This is observational research – it doesn’t prove causality,” says Dr Charlotte Mills, a lecturer in nutritional sciences at the University of Reading, who wasn’t involved in the study. “Is coffee cardioprotective or are healthier people more likely to consume coffee? That said, these findings are consistent with many other observational trials that associate moderate coffee consumption with benefit to cardiovascular health, and so it looks promising.”

Coffee type matters

While it didn’t delve into the ‘whys’ and ‘hows’, the QMUL study did offer up some pointers. Intriguingly, the type of coffee people were drinking seemed to make a difference to their heart health. While ground coffee was associated with decreased mortality over the study period, the same did not apply to instant. Decaf coffee, however, retained the benefits, suggesting that any cardioprotective effect might be due to something other than caffeine.

“Experimental data increasingly supports the antioxidants found in ground coffee might be the key components of this beneficial effect,” says Peterson. “The health impact of caffeine is still debated – although many studies have concluded that long-term coffee consumption has no clinical importance on the risk of hypertension.”

Different coffee types, he explains, have different production processes. That means each contains its own signature blend of chemicals.

“As an example, instant coffee is reported to contain approximately twice as much acrylamide than ground coffee, a substance which has been shown to be neurotoxic and carcinogenic,” he says.

Unfiltered coffee, meanwhile, features high levels of diterpenes, which have been associated with an increase in LDL (bad) cholesterol and diminished heart health. A large Norwegian study from 2020 found that brewing method mattered: unfiltered brew was linked with higher mortality than filtered brew, whereas filtered brew was linked with lower mortality than no coffee consumption at all.

Mills agrees that there’s much more to coffee than the caffeine alone. The beverage contains a number of biologically active compounds – chlorogenic acids, trigonelline, diterpenes, melanoidins etcetera – each of which will have a different impact on health.

“I am particularly interested in the impact of coffee chlorogenic acids on cardiovascular disease risk,” she says. “Chlorogenic acids are a subclass of polyphenols [a type of antioxidant], the same group of compounds that are found in blueberries and cocoa. Coffee is extremely high in chlorogenic acids, and we have demonstrated in randomised controlled trials that they can reduce cardiovascular disease risk. More research is definitely needed to prove this.”

Getting the most from your brew

So, what should coffee consumers take from this debate? Well, most of the research offers a tentative green light to those twice-daily Americanos – and you don’t need to go for the caffeinated option if it gives you the jitters.

“For coffee lovers who might have a sensitivity to caffeine, coffee producers are now utilising more natural processes to remove caffeine and preserve the quality of the coffee,” says De-Garnham. “Our Popyan decaf is processed using fermented sugarcane, and it’s just as delicious as any of its caffeinated counterparts.”

Mills thinks the jury’s still out on the health impacts of coffee. However, if coffee consumers are serious about maximising the benefits, they might want to limit their consumption of boiled, unfiltered coffee so as to avoid the diterpenes. For obvious reasons, they should also steer clear of added cream, sugar or syrup.

“It’s difficult to advocate a specifical preparation method, as the evidence is so scarce,” she says. “However, we know that chlorogenic acids are decreased during the coffee roasting process. Chlorogenic acids potentially contribute towards the observed cardioprotective effects of coffee consumption, so choosing less roasted coffee over darker roasts could carry some benefit.”

Time and again, researchers have found that moderate coffee consumption is relatively harmless at worst, and actively beneficial at best. In other words, it can’t hurt to adopt the philosophy ‘a little of what you fancy does you good’. As well as setting you up for the day, your morning cup of joe might just come with a whole raft of additional health benefits.