A strong morning brew is an invariable staple of many Brits’ daily routines, which might also feature regular office tea breaks, pre-lunch lattes, and mid-afternoon flat whites. We’re a nation of caffeine enthusiasts – even during the last lockdown, when cafés were only permitted to serve takeaways, queues of coffee-seekers snaked along our high streets.
But new research suggests that your habitual caffeine doses aren’t just keeping you awake – they could also be keeping you healthy. A new study has found a correlation between moderate consumption of coffee and tea, both of which are rich in caffeine, and a lower risk of stroke and dementia.
The study, the largest of its kind, followed 365,000 people aged between 50 and 74 for over a decade. Over the research period, 5,079 of the participants developed dementia, and 10,053 went on to have at least one stroke. The study, conducted by Dr Yuan Zhang and his colleagues from China’s Tianjin Medical University, found that those who drank two to three cups of coffee a day (or three to five cups of tea) had a lower risk of suffering from a stroke or dementia. The research suggests that moderate caffeine intake lowers the chances of developing dementia to one in 100, with stroke risks falling to one in 50.
“Even small potential health benefits or risks associated with tea and coffee intake may have important public health implications,” says Zhang. However, the researchers pointed out that the volunteers involved in the study – from the UK Biobank – could represent a more health-conscious sample of people than non-participants. They also added that the volunteers self-reported coffee and tea intake, which could lead to inaccurate responses.
The report is, of course, not the first to have assessed the health benefits of caffeine. In 2017, a major study by the University of Southampton and the University of Edinburgh found that people who drink more coffee are less likely to develop hepatocellular cancer (HCC), the most common form of primary liver cancer. Earlier this year, a study in the British Medical Journal found that advanced prostate cancer sufferers are 16 per cent less likely to die if they are heavy coffee drinkers.
Yet other researchers have, over the years, debated the health implications of caffeine. In 1991, the World Health Organisation listed coffee as a possible carcinogen (it contains acrylamide, a possible carcinogen, but most recent studies have not found a link between ingested acrylamide and cancer). And excessive coffee drinking has been implicated with increased anxiety.
For dietician Helen Bond, this new research is positive. “It reiterates some of the research that’s out there, and I think we’re still going to learn more and more about the benefits of drinking coffee,” she says.
The compounds contained in coffee boast several health benefits, she says. “We know that coffee contains plant compounds called phenolics, which also act as antioxidants. They help protect our cells from damage and may reduce the risk of things like heart disease, cancer, and even things like dementia, by neutralising the damaging free radicals that we get in our bodies from everyday things like pollution, smoking, and so forth.”
“There’s new research also coming through that [suggests] coffee and the compounds it contains might have a positive effect on our gut microbes. And we know that having a diverse, high number of gut microbes is beneficial for our health in lots of different ways.”
“Caffeine is not necessarily essential for a healthy balance in day to day life,” Bond adds. However, she points out that the properties of highly caffeinated drinks like coffee can have health benefits. “We know, for example, that coffee contains a nutrient called potassium, which we know is beneficial for our blood pressure.”
Even so, Bond advises against excessive caffeine consumption and instead suggests finding a moderate middle ground. “Too much caffeine, perhaps in excess of something like 600mg of caffeine a day, has certainly been linked to things like insomnia, anxiety, nervousness and potential irritability,” she says. “It can aggravate irritable bowel syndrome and upset tummies, and sometimes it can push up your blood pressure.”
So how should we find our caffeine sweet spot?
In order to maximise the health benefits of caffeine while avoiding excessive consumption, Bond advises following official health guidelines. “If you’re pregnant, you’re not to have more than 200mg of caffeine a day – roughly no more than two mugs of instant coffee a day – because caffeine is linked to low birth weight. But for the general population, the health organisations say most people can safely consume around 300-400mg of caffeine a day, which roughly equates to four or five cups.”
“If you aren’t sensitive to the effects of caffeine and you enjoy having a good cuppa or a nice brew in the morning, I would definitely say four to five cups of coffee a day [is acceptable]… About 400mg of caffeine a day is perfectly acceptable as part of a healthy, balanced and varied diet.”
However, according to research, you should avoid caffeine consumption at least seven hours before bedtime. A study published in the Journal of Clinical Sleep Medicine found that caffeine taken six hours before bedtime still has important disruptive effects on sleep – so if you go to bed around 10pm, you should aim to have your last cup of coffee at 3pm.
Although the caffeine content in a cup of tea or coffee varies by brand, source and preparation, a cup of coffee generally contains more caffeine than the equivalent amount of tea. So if you’re desperate for an energy boost later in the afternoon, an English Breakfast would be a better option than a cappuccino.
Bond also suggests that coffee drinkers be mindful of where their brew comes from, “in terms of the type of coffee, and also how it’s made. Instant coffee at home will be a lot less potent than the kind you get in a coffee shop.”
“It’s very individual, your response to caffeine,” she points out. “It’s not beneficial for all people. Some are very sensitive to caffeine – for those that have things like irritable bowel syndrome, those that have anxiety, it’s possibly best to opt for decaf coffee.”
For those who don’t like tea or coffee, Bond points out that soft drinks and chocolate contain caffeine. “I’m not advocating everyone to go out and eat chocolate, but even a bit of dark chocolate will naturally [contain] a bit of caffeine.”
“It’s certainly still emerging research that’s coming out, but I think that if you’re a tea or coffee lover, the news that having tea and coffee may potentially be beneficial for our health is welcome news,” Bond says.