For coffee drinkers, it can be difficult to strike a balance between getting enough caffeine to stay energized but not overdoing it and feeling jittery.
However, a new study has pinpointed the ‘sweet spot’ for staying awake throughout the day without the negative consequences.
Using health data from nearly 500,000 people, researchers in China measured each person’s average daily coffee consumption and if they had been diagnosed with a mood disorder, such as depression, or stress-related disorders, such as anxiety and post-traumatic stress disorder (PTSD).
The team found that people drinking two to three cups of coffee per day were at the lowest risk of mood- or stress-related disorders. This was true for regularly caffeinated, instant and decaffeinated coffee, suggesting the protective effect rests in the coffee itself rather than caffeine.
Surprisingly, people who drank less coffee had no measurable mental health advantages or improvements over the group who stuck to two to three cups.
Additionally, the study showed people who regularly drank more than three cups of coffee in a day were at a greater risk of disorders such as depression, anxiety and acute stress disorder.
The researchers discovered a J-shaped association between coffee consumption and mental health outcomes, meaning moderation rather than elimination was key for reaping the benefits.
However, they cautioned the findings show only an association rather than a direct cause and noted more research is needed.
Researchers in China have suggested two to three cups of coffee per day is the ‘sweet spot’ for staying awake without negative consequences (stock image)
‘This study supports that moderate intake is the “sweet spot,” which aligns with current general recommendations for caffeine intake,’ Morgan L Walker, a registered dietitian at Lebanon Valley College who was not involved in the study, told VeryWell Health.
‘Once you start exceeding that range, that is where we tend to see more negative side effects—things like poor sleep, jitteriness, or increased anxiety, especially in people who are more sensitive to caffeine.’
The new study, published in the Journal of Affective Disorders, looked at healthcare data from 461,586 adults in the UK Biobank database. Participants were 57 years old on average, and 54 percent were women.
The participants were followed for 13 years on average, during which 18,220 mood disorders and 18,547 stress disorders were documented.
About 71 percent of the study population reported regularly drinking coffee. Of those, 44 percent said they have two to three cups per day, 28.5 percent had one cup daily.
The team found people drinking two to three cups per day were 10 to 20 percent less likely to have a mood or stress-related disorder compared to non-coffee drinkers.
Meanwhile, the risk of these disorders began to increase after three or more cups, and there were no measurable benefits for people getting less than two to three a day.
Micronutrients called polyphenols in coffee and have been shown to reduce inflammation and cellular damage in the brain, warding off the release of neurotoxins that interfere with neurotransmitters like serotonin, raising the risk of mood disorders.
Coffee can also stimulate the production of feel-good chemical dopamine, lowering the risk of anxiety and boosting motivation.
Additionally, coffee can be a reflection of social support, such as meeting a friend at a coffee shop, which improves mood.
There are several limitations to the study, including the researchers relying on self-reported coffee intake data from the participants. Each person also has a different tolerance to caffeine, so two to three cups is not a one-size-fits-all approach.
