Coffee, probably the world’s favorite perker-upper and pooper-shaker, can have surprising benefits to those with severe mental illnesses, a new study has found. So long as you don’t overdo it, it seems the beverage can slow down the telomere shortening that diseases like bipolar disorder and schizophrenia can cause, taking roughly half a decade off your biological age.
“We know that coffee can help slow biological ageing in the general population, but little is known about its effect on people with severe mental illness – a population whose lifespan is already shortened, in part due to age-related diseases,” said Vid Mlakar, a PhD student at King’s College London and first author of the study, in a statement. “Our study shows that up to four cups of coffee per day is linked to longer telomeres among people with bipolar disorder and schizophrenia.”
“This is comparable to a biological age of five years younger than non-coffee drinkers,” he explained.
How we measure ageing
There are many markers of biological aging, but one of the most reliable is the length of our telomeres. Coming from the Greek “telos”, meaning “end”, and “meros”, meaning “part”, these are basically exactly what they sound like: the end-parts of our chromosomes, sitting at either end like little aglets protecting the DNA material contained in between.
Just like all of our DNA, our telomeres accrue damage as we age. Rather unlike most other places in our genome, however, they can’t repair themselves at all – the enzyme responsible, called telomerase, isn’t expressed in most mammalian bodies. That means the damage just adds up, like the outer wall of a castle fortress slowly degrading over the centuries – so the shorter they are, the “older” we can reasonably assume their owner to be.
But aging, of course, does not come at all of us equally. Our telomere length is strongly inherited and depends on a range of factors, including our sex, race, and ethnicity; maternal stress during pregnancy can affect it, as can paternal age at birth. Being mistreated in childhood shortens them; so does living away from green spaces; so does a sedentary lifestyle and lack of sleep. And of course, that’s not even accounting for the random genetic mutations that nobody could ever predict or counteract.
Then, there’s mental health. “Despite telomere attrition being universal, contemporary research has reported shorter [telomere length] in both patients with schizophrenia and bipolar disorder, compared with unaffected age-matched peers,” the new paper points out. “Researchers still do not fully understand the aetiology of the cellular differences between these two groups [and] one avenue of research has been exploring how diet may have an impact on telomere biology.”
This is where coffee comes in. A handful of studies have hinted that the beverage – the non-instant kind, sorry for you savers out there – might have some protective effects for telomere length, and the researchers wanted to investigate further. After all, “many of the factors that are known to affect biological ageing, such as genetics and negative stressful life experiences, are beyond our control,” said Dr Monica Aas, MRC Research Fellow at King’s College London and senior author of the study. But “lifestyle factors like coffee consumption are something we can actively modify, making research like this particularly valuable.”
Using data from some 436 adults diagnosed with either schizophrenia spectrum or affective disorders – that is, bipolar or major depressive disorder with psychosis – the researchers measured both telomere length and self-reported coffee intake per day. They also collected data on smoking habits, known to both significantly shorten telomere length and also to increase caffeine metabolism.
“To our knowledge, this is the first study in the literature to investigate the association between coffee consumption and [telomere length] in people with [schizophrenia] or affective disorders,” the pair wrote. “Considering previous research in the general population, we anticipate that moderate coffee consumption will be associated with having longer [telomere length], adjusting for confounders.”
But would they be correct?
Could coffee keep you young?
At least superficially, the results couldn’t be clearer. “Our findings indicate an inverted J-shape association between coffee consumption levels and cellular ageing as measured by [telomere length] in patients with a severe mental disorder,” the paper reports – a finding that holds even “adjusted for age, sex, ethnicity, medication, tobacco use and group status.”
And the result even has the good manners to comport with current medical advice on caffeine intake. “Coffee consumption up to the recommended limit of four cups per day was associated with longer telomere lengths,” the researchers write, while coffee drinking past that level didn’t impart a statistically significant benefit.
That said, there are some things to bear in mind. Self-reporting is a notoriously problematic way to measure food and drink intake – and even if participants showed perfect coffee-related recall, the actual survey didn’t enquire much past “how much coffee do you drink per day”. When the coffee was drunk, what type and how strong it was, whether any other caffeine sources were consumed – none of that was recorded, even though its inclusion may have changed the results.
Equally, while a correlation does seem to be there, the team doesn’t know why. “It is our speculation that [telomere length] was increased due to potential conferred antioxidant/anti-inflammatory properties,” they write – but that’s just a hypothesis, since they admit that “we did not have data on peripheral antioxidant/inflammation levels.”
Nevertheless, it’s a new piece of a puzzle that, so far, has gone relatively understudied. And for those of us already nursing a minor caffeine addiction, it’s also a welcome justification for a habit that, ultimately, we were never going to kick in any case.
“Coffee is a beverage that many people consume daily,” Aas said, cautioning that “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 ageing,” she said.
“Studies such as this […] support the idea that we should move away from viewing coffee as simply ‘good or bad’, and instead consider a more balanced view,” she said. “Still, these results need to be confirmed in other independent studies and longitudinal research before we can determine if this is a causal effect.”
The study is published in BMJ Mental Health.
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