A few cups of coffee a day may play a small but meaningful role in helping people with mental illness live healthier, longer lives as long as they drink it in moderation, according to new research.
Scientists at King’s College London examined data from 436 adults and found that drinking up to four cups of coffee daily was linked to longer telomeres the protective caps on chromosomes that indicate cellular aging in people diagnosed with schizophrenia, bipolar disorder, or psychotic depression.
Participants who drank three to four cups a day had telomeres consistent with a biological age roughly five years younger than people who didn’t drink coffee at all.
Too much coffee erases the benefit
But the benefits vanished for those who exceeded four cups a day. In fact, heavier coffee drinkers showed more signs of cellular stress, according to the findings published in BMJ Mental Health.
This “sweet spot” mirrors guidance from the U.S. Food and Drug Administration, which recommends limiting caffeine to around 400 milligrams per day, or about four cups.
Why coffee might help
Past studies in the general population have offered mixed results, but lead author Vid Mlakar, a Ph.D. student at King’s College London, noted that little was known about coffee’s effect on people with severe mental illness a group whose lifespan is typically 15 years shorter than average, often due to age-related diseases such as heart disease or cancer.
Telomeres naturally shorten with age, and the process appears to accelerate in people with serious mental illness. Telomeres are also sensitive to oxidative stress and inflammation, both of which tend to be elevated in these conditions. Coffee’s antioxidant and anti-inflammatory compounds may help protect cells from such damage.
“Coffee is a beverage many people consume daily,” said senior author Dr. Monica Aas, adding that while too much caffeine can harm sleep and overall health, coffee in moderation “may have benefits for biological aging.”
Important limitations
Researchers emphasized that this was an observational study meaning it cannot prove coffee slows aging, only that there’s an association.
Participants self-reported their coffee habits, and researchers had no data on coffee type, serving size, or caffeine intake from other beverages. Larger and longer-term studies are needed to confirm whether coffee truly influences biological aging.
Experts also cautioned that excessive caffeine can cause jitteriness, heart palpitations, and poor sleep.
Dr. Anoop Singh, a psychiatrist at Mindpath Health who was not involved in the study, said the findings align with previous research connecting coffee to healthier aging markers. But he added that telomeres are a “noisy biomarker” helpful for spotting broad trends, but not reliable enough to determine an individual’s biological age.