In the UK, we drink 98 million cups of coffee every single day, and as many as 80% of us visit a coffee shop at least once a week. Coffee drinking has been ingrained in our culture since the first London coffee shop opened back in 1652. Praised for its energising properties, some swear by a daily cup of joe – but how much is too much? And, how does repeated coffee intake affect the body over time? We turn to the science to find out.
How is coffee made?
Coffee begins as seeds, which we call coffee beans, that are harvested from the fruit of the coffee plant. After collection, the beans are processed to remove the outer fruit layer, either through a dry or wet method. Once cleaned and dried, the beans are roasted at high temperatures, which develops their characteristic aroma and flavor. Finally, the roasted beans are ground to the desired consistency and brewed to form the rich, aromatic coffee drink we all know and love.
How much coffee can you drink daily?
Moderate coffee consumption is generally considered safe for most adults. Health experts suggest up to 3–4 cups per day, equivalent to roughly 300–400 mg of caffeine, depending on the strength of the brew (black tea contains around half as much caffeine). Consuming caffeinated coffee above this limit can lead to uncomfortable effects such as insomnia, jitters, or rapid heartbeat. It's worth noting that caffeine affects us all differently and tolerance is individual. If you suffer from any underlying health conditions, it's best to follow your GP's advice on how much to consume.
Does coffee accelerate ageing?
The link between coffee consumption and ageing has been widely studied. There's evidence to support both harmful and beneficial effects and as with many things, the devil is in the details. Research across several journals points towards coffee accelerating biological ageing on a cellular level. Findings from a US study revealed that people who consumed more caffeine tended to have shorter telomeres, which are protective caps on DNA that shrink with age (Tucker, 2017). The higher the dose, the greater the effect.
A UK Biobank study in 2023 took this research one step further and found that certain types of coffee, particularly instant coffee, were associated with shorter telomeres (Zhou et al.). What we can take from this research is that though there is a causal link between coffee and ageing, it's the type and quantity of coffee consumed that matters the most.
Does coffee have health benefits?
“Coffee has been recognized as an effective beverage for healthful aging.”
Other research moves away from effects on a cellular level, instead looking at real-world ageing and longevity. Research found that coffee consumption is associated with lower risk of age-related diseases (like cardiovascular disease and neurodegeneration) and reduced overall mortality (Takahashi & Ishigami, 2017). Benefits are mostly linked to the health benefits of antioxidants and polyphenols (plant compounds) found in whole coffee, which can reduce oxidative stress and inflammation — factors linked to chronic diseases.
Turn coffee into a healthy habit
To maximise the health benefits of coffee while minimising its potential harmful effects on ageing, it's best to consume moderate amounts of freshly-ground filtered or drip coffee made from whole beans, preferably medium or dark roasted to preserve antioxidants and polyphenols. Avoid excessive caffeine intake, which can accelerate biological ageing, plus aggravate insomnia and anxiety, and limit heavily processed or instant coffees that have been linked to shorter telomeres. This approach best balances the anti-ageing, anti-inflammatory, and longevity-promoting effects of coffee.
Top image credit: Getty Images
