Why your daily cup of coffee is good for your health 

A moderate caffeine intake is linked with a lower risk of some cancers and a reduced likelihood of developing heart disease, Parkinson's and type 2 diabetes

Picture: iStock 

Andrew Fitzgerald converted to coffee when he moved from Cork to San Diego 12 years ago. “I used to drink so much tea that I could have been an ambassador for Barrys,” he jokes.

But nobody drinks tea on America’s east coast. “Everyone meets for chats over coffee, so I had to try it,” says the 46-year-old. “I loved the taste and now it’s become a daily habit.”

He starts the day with an Americano. “Making and drinking it is a little bit of me-time at the start of the day,” he says. “The caffeine buzz sets me up for the day too.”

He has another Americano at 11am. “Then that’s it,” he says. “I’d get too buzzy if I had more.”

We Irish may be known as tea drinkers but statistics show that, like Fitzgerald, more of us are discovering the pleasure of drinking a ‘cuppa joe’.

Bewley’s Coffee Consumption Report 2021 found that 78% of Irish adults drink coffee daily. They consume an average of three cups and 41% of them stated that doing so was essential to their day.

Jeffrey Long, managing director of Irish coffee roasters Java Republic, identifies several reasons for our growing interest in coffee.

“It’s been driven by changing lifestyles, cultural shifts and a heightened appreciation for quality beverages and food,” he says. “Coffee is now a means of socialising with friends, with many favouring cosy cafés over busy bars. For younger people, there is coffee’s association with being grown-up and sophisticated. And in these busy times, the ritual of taking a break to have a cup of coffee can give all of us a much-needed moment for pause or reflection.”

The trend has even travelled from urban centres to more peripheral areas such as West Kerry. It may not always have been coffee central, but it is now a great place to get a good brew thanks to speciality coffee shops such as Bean in Dingle.

“We’ve noticed a definite coffee boom since we opened in 2015,” says one of the owners Luke Burgess.

He thinks there are two main reasons for this. “I’d say it’s a combination of the taste of coffee and the buzz of energy it gives,” he says. “Lots of our customers love coffee and are interested in its flavour notes, the origins of the beans and the way it’s been processed and roasted. We also see many people who like to start their day with coffee to wake them up.”

Even coffee sceptics can be won over by frappuccinos, the iced coffee drinks flavoured with syrup and topped with cream, particularly popular with younger coffee drinkers. “They probably prefer them as they have a sweet and creamy taste that masks the acidity and bitterness of coffee,” says Long.

They are also tempted by the likes of cold brew and bubble tea. “Gen Z and millennials like to order unique drinks or drinks that have that visually appealing Instagram look so they can share pictures of them on social media,” says Long.

Health benefits

Years ago, the very idea of young people being encouraged to drink coffee would have raised alarm bells in medical circles. Coffee is high in caffeine, which stimulates our central nervous system and used to be considered bad for us. It was thought to be a cause of conditions such as heart disease, stroke and type 2 diabetes and the World Health Organization warned that it could cause cancer.

“There’s been a huge shift in that negative perception,” says Rachel Kumar, a registered dietitian at the Dublin Nutrition Centre. “Recent research has upended it by uncovering a range of potential health benefits for moderate coffee drinkers. Caffeine is now associated with lower risks of some cancers, heart disease and type 2 diabetes.”

This research includes a landmark review that was published in the British Medical Journal in 2017. It linked a moderate caffeine intake with a lower risk of breast, colorectal, endometrial and prostate cancers as well as a reduced likelihood of developing cardiovascular disease, Parkinson’s disease and type two diabetes. The review concluded that drinking coffee was healthier than abstaining by showing that those who consumed a moderate amount were less likely to die early than those who didn’t drink coffee at all.

Also, two significant studies were published last year. One examined data from 389,505 participants and found that drinking coffee lowered the risk of cognitive disorders such as dementia. The other involved 152,821 participants and showed that drinking two to three cups of coffee a day was associated with a reduced risk of depression and anxiety.

Before we were ever aware of these health benefits, many of us were drawn to coffee for its potential to enhance our alertness and concentration. Professor of physiology at the University of Limerick and creator of the Inside the Brain website, Dr William O’Connor, explains how it does this.

“Once consumed, caffeine is absorbed in the stomach and small intestine and circulated throughout the body to target muscles and organs,” he says. “It increases our breathing and heart rate, which consequently increases oxygen and energy supply and can even speed up our movements. It also increases the circulation of the stress hormones cortisol and adrenaline, which can make us feel refreshed and focused.”

Caffeine can also boost our energy levels when we’re flagging. It does this because of its similarity to the neurotransmitter adenosine. Adenosine binds to receptors in the brain over a day to gradually slow down nervous activity and produce a feeling of tiredness.

“If you drink coffee, caffeine inserts itself into these receptors, preventing adenosine from slowing neurons down and keeping them awake instead,” says O’Connor.

Kumar stresses that there is a caveat when it comes to drinking coffee: its proven health benefits depend on drinking it in moderation. “If consumption exceeds 400mgs a day, which is about four regular cups of coffee, its effects can become negative,” she says.

Our bodies can manage caffeine at lower doses, “but higher doses can lead to nervous overstimulation,” says O’Connor. “Adenosine has an important role in calming the nervous system and when it’s blocked by too much caffeine, this can lead to headaches, anxiety, problems sleeping, dizziness, irritability, tinnitus, tachycardia (rapid heartbeat) and even seizures.”

Some people are advised to minimise their caffeine intake to even less than 400mg per day. “Pregnant and breastfeeding women shouldn’t consume more than 200mg, which is two cups of coffee, and because of its stimulant effects, children shouldn’t have any,” says Kumar.

As for teenagers, O’Connor recommends they limit their intake to less than 100mg (one cup) a day.

Some are more sensitive to the effects of caffeine. “Everyone is different and in some people, even small doses can lead to insomnia, headaches and anxiety,” says O’Connor.

Drinking too much 

At the other end of the spectrum, it is possible to drink an excessive amount of coffee and become dependent on it. Research carried out by Johns Hopkins Medical Centre in America examined data from 1,006 coffee drinkers and found that approximately 8% met the criteria for dependency.

Forty-year-old Aisling Owens Nash from Kildare believes that she was once addicted to caffeine.

“I started drinking milky coffee as a teenager and moved on to mochas in college,” she says. “By the time I was a busy working mum, I was having two espressos before leaving the house in the morning, picking up a mocha on the way to work and drinking coffee throughout the day. I was an addict.”

Her high caffeine intake took a toll on her physical and mental health. “I constantly felt agitated and stressed,” she says. “At one point, I was sent for heart tests due to palpitations and arrhythmia. I was always nauseous too.”

According to O’Connor, when people drink too much coffee it creates a cycle of heightened anxiety that can only be alleviated by more caffeine. Any attempt to break this cycle will lead to withdrawal symptoms such as headaches.

“People who abruptly stop consuming caffeine experience a change in the activity of their nervous system,” says O’Connor. “This can manifest as tiredness or general flu-like feelings that last a few days. Caffeine also narrows the blood vessels, so when you stop, your blood vessels open up and that extra blood flow to the brain can cause headaches.”

Owens Nash found that staying hydrated helped ease her headaches. It’s one way of taking the edge off withdrawal symptoms.

Kumar advises a gradual weaning process rather than going cold turkey. “Alternate between decaf and regular coffee to start and cut down from there,” she says O’Connor adds that it helps to practice stress-reduction techniques, get adequate sleep and take painkillers for the headaches as directed.

Two billion cups of coffee are brewed daily, and it’s easy to see why. It wakes us up to the world, sharpens our focus and gives us the energy we need to live our busy lives.

However, it is possible to get too much of this good thing, which can wreck our sleep, leave us feeling anxious and jittery and even lead to dependency. The takeaway when it comes to coffee is to find the balance that works for you.

How much caffeine is in your favourite brew?

The European Food Safety Authority recommends a caffeine consumption of up to 400mg per day.

That’s approximately four cups of coffee if you make them at home.

However, it can be difficult to gauge your caffeine intake when you drink coffee in cafés or experiment with different coffee drinks.

So, here’s the breakdown of the most common coffee beverages served in Irish cafés and what you can expect to find in your brew of choice.

 A single espresso contains an average of 80mg of caffeine.

• An Americano is an espresso with hot water added. It has approximately 80mg of caffeine.
• A latte usually consists of a single shot of espresso combined with steamed milk, with a small amount of foam on top. It has about 80mg of caffeine per cup.
•  A cappuccino is a shot of espresso combined with steamed milk topped with a layer of frothed milk. A single cappuccino should provide 80mg of caffeine.
• A flat white is a more robust and less frothy variation on cappuccino. It contains an average of 150mg of caffeine.
•  A mocha is a cappuccino with added chocolate powder or syrup. It has about 85mg of caffeine per cup.
•  Cold brew coffee is made by steeping coffee grounds in cold water for up to 24 hours. This produces a concentrated coffee essence that is then diluted with water and can contain up to 200mg of caffeine per cup.
• Instant coffee is made from freeze-dried or spray-dried coffee. It’s one of the most consumed coffee types in Ireland; its caffeine content ranges from 30 to 90mg per cup, depending on the brand.
•  Pods and capsules contain an average of 60 to 80mg of caffeine per cup.
•  Filter and cafetiere coffee is prepared by pouring hot water over ground coffee beans in a filter or cafetiere jug. The average cup of filtered coffee contains 95mg of caffeine.
• Decaf coffee is made by processing coffee beans so that about 97% of the caffeine is removed. A typical cup of decaf has about 2mg of caffeine.