A new study in BMJ Mental Health suggests that drinking up to four cups of coffee a day is associated with slower biological aging in people with severe mental disorders, reflected in longer telomeres—chromosome caps linked to cellular aging. The observed difference in telomere length corresponds to roughly five extra years of biological youth compared with non-coffee drinkers, while higher intake shows no such benefit and may contribute to cellular stress.
Researchers working on the Norwegian Thematically Organised Psychosis (TOP) study analysed data from 436 adults enrolled between 2007 and 2018, according to a summary from BMJ Group and the study authors. The group included 259 people with schizophrenia spectrum disorders and 177 with affective disorders, such as bipolar disorder and major depressive disorder with psychosis.
Participants self-reported how much coffee they drank each day and were grouped into four categories: no coffee (44 people), 1–2 cups, 3–4 cups (110 people) and 5 or more cups. They also provided information on smoking habits and how long they had smoked.
Smoking was common in the sample: about three-quarters of participants (77%, or 337 people) were smokers, with an average smoking history of about nine years. Those drinking five or more cups of coffee per day tended to be older and had smoked for significantly longer than people in the other coffee-intake groups, and participants with schizophrenia drank more coffee on average than those with affective disorders.
To assess biological aging, the researchers measured telomere length in white blood cells (leucocytes) taken from blood samples. Telomeres are protective caps at the ends of chromosomes, often compared to the plastic tips on shoelaces, and they naturally shorten with age. People with major psychiatric conditions such as psychosis, schizophrenia and bipolar disorder typically show faster telomere shortening than the general population.
The findings, reported in BMJ Mental Health and summarised by BMJ Group and ScienceDaily, revealed an inverted J‑shaped association between coffee intake and telomere length. Compared with participants who drank no coffee, those consuming three to four cups a day had longer telomeres. After adjusting for age, sex, ethnicity, tobacco use, diagnosis and current treatments, telomere lengths in participants drinking around four cups a day corresponded to a biological age approximately five years younger than that of non-coffee drinkers. This pattern was not seen in the group drinking five or more cups per day, where the apparent benefit disappeared.
Because this was an observational, cross-sectional study, the authors emphasise that it cannot prove that coffee directly slows cellular aging. They also lacked detailed information on potentially important factors, including the type of coffee consumed, when it was drunk, exact caffeine content and intake of other caffeinated beverages.
Coffee contains a range of antioxidant and anti-inflammatory compounds, which the researchers suggest could help counteract oxidative stress and inflammation—two processes that can accelerate telomere shortening, particularly in people with severe mental illness. As they note, telomeres are highly sensitive to both oxidative stress and inflammation, providing a plausible biological explanation for the association between moderate coffee intake and longer telomeres in this group.
The reported "sweet spot" of three to four cups a day broadly aligns with guidance from health agencies such as the UK National Health Service and the US Food and Drug Administration, which advise keeping daily caffeine intake at or below about 400 mg, roughly equivalent to four standard cups of coffee.
Coffee is among the most widely consumed beverages worldwide. BMJ Group cites estimates that global coffee consumption reached about 10.56 billion kilograms in the 2021–2022 period, underscoring the potential public-health relevance of even modest biological effects.
The authors call for further research to confirm their findings, explore underlying mechanisms and determine whether similar associations are seen in the general population and in other psychiatric groups. For now, they conclude that coffee consumption within commonly recommended limits is linked to longer telomeres in people with severe mental disorders, but that heavier consumption does not appear to offer additional cellular aging benefits and may instead contribute to cellular stress.
