Four cups of coffee a day may slow ageing in people with severe mental illness – study
Moderate coffee consumption—three to four cups a day—may help slow biological ageing in people living with severe mental illness, according to a BMJ Mental Health study.
What you need to know:
- A Norwegian study involving 436 adults with schizophrenia, psychosis, and affective disorders has identified a J-shaped relationship between coffee intake and telomere length.
- Participants who drank 3–4 cups daily had significantly longer telomeres, even after adjusting for smoking and other factors.
Drinking up to four cups of coffee a day may help slow biological ageing in people living with severe mental illness, new research shows.
Findings published in the open-access journal BMJ Mental Health suggest that consuming 3–4 cups daily is linked to longer telomeres (markers of cellular ageing) equating to about five extra “biological years” compared to non-coffee drinkers. Higher intake, however, appears to cancel out these benefits and may increase cellular stress.
Notably, the study found no protective effect when coffee consumption exceeded the 3–4 cup threshold, which aligns with recommendations from major health agencies, including the NHS and the US FDA.
Telomeres, which cap the ends of chromosomes like plastic tips on shoelaces, naturally shorten with age. This process occurs faster in people with psychiatric conditions such as psychosis, schizophrenia, and bipolar disorder. Because telomere length can be influenced by lifestyle factors, researchers investigated whether moderate coffee consumption might slow this shortening in individuals with severe mental illness.
The study involved 436 adults enrolled in the Norwegian Thematically Organised Psychosis study between 2007 and 2018, 259 with schizophrenia and 177 with affective disorders, including bipolar disorder and major depressive disorder with psychosis. Participants reported their daily coffee consumption and were grouped into four categories: none, 1–2 cups, 3–4 cups, and five or more cups. Researchers also documented smoking history.
Participants who consumed five or more cups daily were generally older, and people with schizophrenia drank more coffee than those with affective disorders. Smoking—known to affect caffeine metabolism, was prevalent, with 77 per cent of participants identifying as smokers and averaging nine years of smoking. Those drinking five or more cups had smoked the longest.
Researchers measured telomere length using white blood cells and observed a J-shaped pattern: those drinking three to four cups daily had longer telomeres than non-drinkers, while the group consuming 5 or more cups showed no such advantage. After adjusting for age, sex, ethnicity, smoking, diagnosis, and ongoing treatment, the 4-cup group still displayed telomere lengths associated with a biological age roughly five years younger.
Because the study was observational, the authors emphasise that it cannot prove that coffee directly slows ageing. The researchers also note that they lacked data on the type of coffee consumed, timing, caffeine levels, and intake of other caffeinated drinks.
However, they note that coffee contains powerful antioxidant and anti-inflammatory compounds that may help protect cells from age-related damage. The researchers explain that telomeres are especially vulnerable to oxidative stress and inflammation, factors that could accelerate ageing, making it plausible that coffee consumption helps slow cellular ageing in this already high-risk population.
Coffee is among the world’s most popular beverages, with global consumption reaching an estimated 10.56 billion kilogrammes in 2021–22. Despite its potential benefits, the researchers warn that exceeding recommended limits may contribute to cellular damage and telomere shortening through oxidative stress. International health authorities advise keeping daily caffeine intake at or below 400 mg, the equivalent of about four cups of coffee.
