Catherine Conlon: Drinking coffee could help support healthy ageing

Twenty years on from the original Devil Wears Prada film, and that line from Miranda Priestly, played by Meryl Streep, about her coffee still resonates: “Is there some reason that my coffee isn’t here? Has she died or something?”

Delivered with her signature icy demeanour, it summed up the demanding nature of the fashion queen.

Coffee means a lot to a lot of people and has done for centuries. Johann Sebastian Bach sang about his love of it when he composed The Coffee Cantata in 1732, while modern stars like Leonardo DiCaprio have started their own coffee brands.

The French philosopher, Voltaire, was reputed to drink up to 50 cups per day because he loved it so much. Others use it to kickstart the day, to give them a pick-me-up in the middle of the afternoon, or as a tool to connect with friends and family.

Martin Luther King Jr saw coffee as more than just a drink. He spoke about it in his sermons, describing how every cup we enjoy connects us to people around the world, heightening the idea of our shared humanity and dependence on each other.

Now, a new study shows how coffee is more than just a delicious stimulant - it appears to support healthy ageing in women.

The research, presented at the annual meeting of the American Society for Nutrition in Orlando in June, indicates that drinking coffee may increase women’s chances of not having major chronic diseases and physical or mental limitations as they get older.

A previous review paper published in the British Medical Journal (2017) suggested coffee may offer several health benefits, including minimising the risk of Parkinson’s disease, liver disease and type 2 diabetes. Now, this recent research goes a step further, suggesting that for women, regular caffeine intake increased the chances of having no physical function limitations, memory complaints, mental health impairments, cognitive decline or major chronic diseases.

The researchers defined healthy ageing according to strict criteria: living to at least 70 years old; not having 11 major chronic diseases, including heart disease, type 2 diabetes, stroke and cancer; being free of physical functional limitation; free of mental health or cognitive impairments; and having no memory complaints.

Data was collected from the Nurses’ Health Study that included information from 47,513 female nurses under the age of 60 who were followed for 30 years, starting in 1986. The women were asked about their diet, including questions about the consumption of coffee, tea, cola and decaffeinated coffee.

They then analysed how many of these women met their requirements for healthy ageing, with researchers looking at questionnaires from 2014 and 2016. In 2016, researchers determined that 3,706 (7.7%) of the women met their criteria and found the link to their caffeine intake.

Most caffeine intake came from coffee, and the median caffeine consumption at baseline was 315mg daily. A typical cup of coffee contains 80 to 100mg of caffeine.

Total caffeine intake increased participants’ chances of experiencing healthy ageing.

The study did not find an association between drinking decaffeinated tea or decaffeinated coffee and the likelihood of healthy ageing.

Not surprisingly, the consumption of cola was negatively associated with healthy ageing. The researchers found that each additional small glass of cola was associated with a 20-26% lower likelihood of healthy ageing.

Lead author, Sara Mahdavi, adjunct professor in the Department of Nutritional Sciences at the University of Toronto, Canada, outlined how moderate consumption of caffeinated coffee in midlife was linked to healthy ageing in later life.

“Each additional cup of coffee was linked to about a 2% higher chance of healthy ageing, while cola was associated with a 20% lower chance. The association appeared to be dose-responsive for coffee, though modest, and was not observed with decaf or tea, possibly due to lower intake and differences in bioactive content”.

There are some qualifications to the findings. The study population only included women and the majority were white. The researchers suggested it would be useful to look at other populations as well as other age ranges and healthy ageing outcomes.

Further review studies are needed to support the theory that moderate amounts of coffee daily could promote healthy ageing.

Professor Mahdavi said while the findings were significant, she also advised caution. The study found an association between coffee and healthy ageing, not a cause-and-effect relationship. The researchers advised that generally drinking up to two coffees a day should be safe and beneficial to people but drinking more than that may not be healthy for some, though it may offer additional benefits to others. And there are other factors that are more important to healthy ageing that drinking coffee cannot replace.

“Women who aged best were also more likely to eat well, exercise regularly, and avoid smoking - those behaviours matter much more,” Mahdavi said, adding that more is not necessarily better.

“The clearest benefits were seen with moderate caffeine intake - about 2 to 4 cups a day.”

The good news is that for many of us, enjoying a few cups of coffee in the first half of the day is now encouraged for healthy ageing. As important is the clear evidence of the benefits of reducing sugary drinks for healthy ageing.

Two decades later, it appears Miranda Priestly, as well as being a fashion icon, knew the true value of her daily coffee.

• Dr Catherine Conlon is a public health doctor in Cork