Coffee consumption may slow biological aging in people with severe mental illness, a new study suggests.

In a cross-sectional study of adults with schizophrenia, bipolar disorder, or major depressive disorder with psychosis, drinking three to four cups of coffee daily — but not exceeding this amount — was associated with longer telomere length, a marker of biological aging.

The effect was comparable to a biological age roughly 5 years younger than noncoffee drinkers.

“On one hand, we know that excessive coffee consumption can have negative effects on health, such as reducing sleep quality. However, our new study suggests that coffee consumption up to a certain point may have benefits for biological aging,” senior author Monica Aas, PhD, with King’s College London, London, England, said in a news release.

“Studies such as this also support the idea that we should move away from viewing coffee as simply ‘good or bad,’ and instead consider a more balanced view. Still, these results need to be confirmed in other independent studies and longitudinal research before we can determine if this is a causal effect,” Aas added.

The study was published online on November 25 in BMJ Mental Health.

Telomere Protection in a Cup?

Telomeres are repetitive DNA sequences and proteins that cap the ends of chromosomes and help to prevent cellular deterioration. Telomere shortening is a natural part of aging, but the process has been shown to be accelerated in people with severe mental illness, who have an average life expectancy 15 years shorter than the general population.

Previous studies have shown a link between coffee consumption and some health benefits in the general population, such as reducing oxidative stress, which may help prevent telomere shortening. But the relationship between coffee drinking and telomere length in psychiatric populations remains unclear.

To investigate, investigators analyzed data from 436 adults, in the Norwegian Thematically Organized Psychosis study, who were diagnosed with schizophrenia-spectrum or affective disorders.

Participants self-reported their average daily coffee intake, grouped into four categories ranging from no coffee to five or more cups daily. Telomere length was measured from blood samples using quantitative real-time polymerase chain reaction, producing a telomere-to-single-copy-gene ratio. Statistical models were adjusted for age, sex, ethnicity, smoking history, and psychotropic medication doses.

Reduced Cellular Aging

The researchers observed an inverted J-shape between telomere length and coffee intake. Telomere length peaked in those drinking three to four cups daily and was significantly longer than in nondrinkers, the authors found.

Those consuming up to four cups daily had telomere lengths corresponding to roughly 5 fewer years of cellular aging, based on known rates of telomere attrition.

Above this limit, however, telomere length declined, matching concerns about the negative physiological effects of high caffeine intake.

The relationship did not differ between men and women or between schizophrenia and affective disorder diagnoses, suggesting a consistent pattern across psychiatric subgroups, the researchers said.

Investigators cautioned that the observational nature of the study precludes any conclusions about cause and effect. Coffee intake was self-reported in broad categories, without distinguishing between instant and filtered coffee, caffeine content, or other caffeine sources such as tea or energy drinks — all factors that may influence biological effects.

The study also lacked data on inflammatory or oxidative stress markers that could help explain the mechanisms involved. Despite these caveats, investigators noted that the research is the first to document a dose-specific link between coffee consumption and telomere length in people with severe mental disorders.

“Our study contributes to a new understanding of both the potential protective and detrimental effects of coffee consumption on (telomere length) in a psychiatric population, deserving further attention,” the authors wrote. “As people with severe mental disorders tend to have high coffee consumption, our study suggests potential health benefits by monitoring coffee consumption to reduce intake above the recommended daily dose.”

Fuel for an Emerging Debate

In a statement from the UK nonprofit Science Media Center, Elizabeth Akam, PhD, Loughborough University, Loughborough, England, noted that this research “adds to emerging debate around the benefits of coffee and its associated bioactive compounds, including but not limited to caffeine and its metabolites.”

Akam said a noteworthy limitation of this study is that it treats coffee as if it were a single substance.

“However, coffee contains many different compounds, and we don’t know which of these were administered, in what doses, or how much actually ended up in the bloodstream,” Akam said.

“To truly establish a link, positive or negative, between coffee, caffeine, and antioxidant capacity for telomere length, future research should consider leukocyte telomere length and the levels of different compounds in coffee — such as caffeine — in the blood,” she added.

This study was funded by the Research Council of Norway, the KG Jebsen Stiftelsen, and a Medical Research Council Fellowship. The authors declared no competing interests. Akam has previously been employed by AstraZeneca. Akam has conducted caffeine CYP450 genotype analysis aligned to British Swimming and CYP450 variation studies in different global populations alongside telomere length studies aligned to sporting modalities.