Drinking caffeinated coffee three times a day can lower your anxiety – this is the surprising reason why

It might sound counterintuitive. But according to a new study published this week, drinking two to three cups of caffeinated coffee a day can lower your risk of anxiety. Scientists from University College, Cork, found that hitting the hot-beverage ‘sweet spot’ was linked to a lower risk of stress, depression and impulsivity. This is because of the effect caffeine has on your microbiome, the trillions of friendly bacteria, fungi and viruses that populate your digestive system.

The new study, published in Nature Communications, adds to a growing body of research about the health benefits of your daily espresso. Professor John Cryan is a neuroscientist at University College, Cork, and lead author of the paper. ‘The relationship between digestive and mental health is increasingly being better understood,’ he says. ‘Coffee may modify what the microbes in our microbiome do collectively, and what metabolites – or molecules – they use.’

Full of beans

The study – which showed an association between lowered anxiety in coffee drinkers, rather than proving that coffee caused this calmness – suggested that both caffeinated and decaffeinated coffee were associated with changes in the gut microbiome, as well as differences in mood and stress.

But whereas decaff led to improved learning and memory, the full-powered version of coffee was the most likely to reduce anxiety and improve attention.

Why so? The Irish study follows a similar paper published earlier this year in the Journal of Affective Disorders. ‘Moderate caffeine consumption influences brain chemicals linked to mood and motivation, particularly dopamine,’ says Dr Tom McLaren, a consultant psychiatrist who works at Re:Cognition Health.

‘This also reduces fatigue and may support cognitive function, indirectly boosting mood.’ The decaffeinated version does not have the same effect.

Knowing where to stop

Two to three cups is the perfect amount because it’s enough to boost alertness, concentration and energy without triggering the physiological stress response that comes with higher doses.

‘In clinical practice, we often see that moderate stimulation can support mood and functioning, while higher levels of caffeine tend to increase anxiety, irritability and sleep disruption,’ says Dr McLaren.

‘On the other hand, people drinking more than four or five cups a day – especially if they experience anxiety or poor sleep – may benefit from gradually reducing their intake and noticing whether their symptoms improve,’ he advises. The message is: keep an eye on your caffeine intake before you go from high-performing superhero to jittering wreck.