'Regular' Coffee Drinking May Reduce Anxiety, Study Finds

There’s no doubt that too much caffeine – the NHS draws the line at 600mg a day, or roughly two large to four smaller cups – can make us shaky, give us the runs, and leave us anxious. 

But new research has found that “regular” caffeinated coffee drinkers might have less anxiety and a better mood, on average, than those who didn’t drink coffee at all.

While both decaf coffee was associated with better learning and memory, only those who drank caffeinated coffee also enjoyed reduced anxiety, better attention, and reduced inflammation.

Three to five cups a day seemed to be the sweet spot 

In this research, scientists looked at 31 participants who drank three to five cups of coffee a day, which the European Food Safety Authority describes as a “moderate” amount.

The other 31 participants usually drank no coffee at all.

They were given psychological tests, and gave stool and urine samples throughout the study. 

For the first two weeks, coffee drinkers were asked to avoid drinking coffee. Their gut microbiomes changed a lot during that time, unlike those who never drank coffee to begin with; former coffee drinkers lost some bacteria usually associated with getting rid of bad gut bacteria and protecting the stomach.

After that period, researchers gave both groups either caffeinated or decaffeinated coffee again (the participants didn’t know which they had been given). 

Both the caffeinated and decaffeinated coffee drinkers got better scores for stress, impulsivity, and depression after drinking three to five cups a day. Only caffeinated coffee drinkers reported lower anxiety levels and better vigilance, while decaf coffee drinkers enjoyed better learning and memory abilities. 

And a decrease in inflammation was seen only among those who drank caffeinated coffee. 

Researchers think this might be down to the gut health changes linked to coffee consumption

Professor John Cryan, the study’s corresponding author, said: “Public interest in gut health has risen hugely. The relationship between digestive and mental health is also increasingly being better understood, but the mechanisms behind coffee’s effects on this gut-brain axis have remained unclear.

“Our findings reveal the microbiome and neurological responses to coffee, as well as their potential long-term benefits for a healthier microbiome. Coffee may modify what microbes do collectively, and what metabolites they use. As the public continues to think about dietary changes for the right digestive balance, coffee has the potential to also be harnessed as a further intervention as part of a healthy, balanced diet.”

Calling coffee “more than just caffeine,” he added, “it’s a complex dietary factor that interacts with our gut microbes, our metabolism, and even our emotional well-being. Our findings suggest that coffee, whether caffeinated or decaffeinated, can influence health in distinct but complementary ways.”