Britons drink 95 million cups of coffee every day, and scientists increasingly believe the habit does far more than help people wake up. Studies suggest coffee can benefit the brain, liver and bones, with up to five cups a day considered the ideal dose.
Coffee combines caffeine, which boosts alertness and physical performance, with anti-inflammatory polyphenols that scientists believe can lower the risk of dementia, heart disease, frailty and premature death. Experts now believe those benefits differ depending on age. Older adults may see greater heart health improvements from the accumulation of blood-boosting compounds over time, while women at menopausal age may be more vulnerable to caffeine's anxiety-inducing effect.
Here is what experts say about the ideal amount of coffee at each stage of life.
At least two cups a day in your 30s, even if it's decaf
Experts increasingly believe the thirties are when many chronic diseases that emerge later in life first take root. One study tracking more than 350,000 UK adults aged over 37 found that those who drank five or more cups of coffee a day had a significantly lower risk of liver cancer than non-coffee drinkers, and were around a third less likely to develop cirrhosis, in which the liver becomes permanently scarred. The benefits were seen even among decaffeinated coffee drinkers.
Scientists believe the protective effect comes from polyphenols, compounds that reduce inflammation and oxidative stress throughout the body. These antioxidants may also help protect the brain from dementia decades before symptoms appear. One study tracking more than 130,000 people over 40 years found that those who routinely drank two to three cups of coffee had a 20 per cent lower risk of dementia.
Alex Manos, health and performance director at Exhale Coffee, said: "Polyphenols protect your brain by passing through the blood-brain barrier to reduce neuroinflammation, stimulate the growth of new neurons, and optimise blood flow."
He said coffee should be viewed as a long-term investment rather than a quick fix. "Lifestyle practices should be viewed as long-term interventions," he said. "The biological imbalances that lead to dementia can start more than two decades before a diagnosis."
Three small cups in your 40s, if you're a woman
Coffee's protective effect appears to peak around age 48, according to research. Harvard researchers analysed data from more than 47,000 women aged 45 to 60 and found those who drank three small cups a day were 13 per cent more likely to see mental and physical benefits in their 70s and beyond. Each additional cup was linked to a two per cent higher chance of being free from major chronic disease and in good mental and cognitive health.
"Those who drank moderate amounts of caffeinated coffee [at that age] were more likely to age in good health over the next 30 years," said Dr Sara Mahdavi, the study's lead author.
Mahdavi stopped short of suggesting all women should start drinking coffee. "For women who already consume caffeinated coffee and tolerate it well, the findings are reassuring," she said. "The results suggest that small, consistent habits can shape long-term health."
Experts believe fluctuating female sex hormones at this stage of life influence how quickly caffeine is broken down, which may explain why the effect is seen mainly in women. For some, however, hormonal changes during perimenopause, which occurs between roughly 45 and 55 for most women, can increase sensitivity to caffeine, worsening anxiety, palpitations and sleep disturbances.
Up to five cups a day could help the heart and liver after 50
Turning 50 often brings a reminder that the risk of heart disease and stroke begins to climb, and for decades experts warned that too much caffeine could strain an ageing heart. Newer evidence is more reassuring. Earlier this year, the American Heart Association concluded that most healthy adults can safely consume five cups of coffee a day in midlife without increasing their risk of cardiovascular disease.
That does not mean everyone over 50 should start drinking five cups immediately. Dr Neil Clarke, an expert at the Institute for Scientific Information on Coffee, said caffeine tolerance remains highly individual and can change with age. "Some older adults may benefit from adjusting intake according to their caffeine sensitivity, sleep quality, and any medical conditions or medications," he said.
Three to five cups daily could beat frailty in old age
Frailty is one of the leading causes of death among elderly people in the UK, dramatically raising the risk of potentially lethal injuries. Coffee could help slow physical decline. A study published in the European Journal of Nutrition tracked more than 1,100 adults aged 55 and over for seven years and found that drinking four to six cups a day in your 60s was associated with a reduced risk of frailty, along with improvements in strength, walking speed, physical activity levels and healthy weight management.
Dr Clarke said caffeine may also help older adults stay physically active. "Caffeine may improve exercise performance, reduce perceived effort, and increase training capacity, helping older adults remain physically active," he said.
People who drink at least two cups of coffee from age 40 onwards have also been shown to have more muscle mass than non-drinkers in later life. Scientists believe coffee may boost autophagy, the process by which cells break down and repair themselves, which is important for maintaining muscle, while its anti-inflammatory properties may protect against age-related muscle loss. Studies have found this effect to be stronger in men than in women.
