Despite Ireland being a traditionally tea-drinking nation, the proliferation of coffee shops attests to the fact that three-quarters of Irish adults now drink coffee.
According to Ailbhe Byrne of the Irish Coffee Council (ICC), in 2009 just under 4,000 tonnes of coffee were consumed in the country. "By 2014 this had jumped to over 4,558 tonnes and, in 2015, the retail value sales of all coffee amounted to €90.7 million," she says.
In his essay Coffee culture in Dublin: a brief history, Dr Máirtín Mac Con Iomaire notes that the coffee phenomenon started here in the 17th century. Four centuries later, "[I]n 2008 when Stephen Morrissey won the coveted title of World Barista Champion, Ireland's place as a coffee consuming country was re-established."
We have read the reports about the sugar content in many coffee-based drinks but what about any health benefits?
In a review published in the journal Integrative Medicine Research in 2014, Korean researchers state coffee is not only the main source of the neurotransmitter caffeine in many populations, it also contains thousands of different chemicals including carbohydrates, lipids, vitamins, alkaloids and phenolic antioxidants. And most readers will confirm that caffeine increases alertness and promotes attentive behaviour.
Two specific ingredients of coffee – cafestol and kahweol – have anti-carcinogenic effects, and another ingredient, chlorogenic acid, exerts both antioxidant and anti-carcinogenic effects. These three compounds help to explain the recent finding by Japanese researchers who this year reported in the European Journal of Cancer Prevention a significant association between coffee consumption and a decreased risk of bladder cancer.
The study involved more than 73,000 individuals, aged 40 to 79 years, who provided information on coffee consumption and lifestyle, and were followed up for between 13 and 17 years, in which time 274 (202 male, 72 female) cases of bladder cancer occurred.
Compared with those who never drank coffee, those who drank occasionally (one to two cups a day) or drank three or more cups a day had a lower risk of bladder cancer. It’s thought that cafestol, kahweol and chlorogenic acid may exert their anti-cancer effects during storage in the bladder.
Mounting evidence
Last March researchers writing in the
European Journal of Nutrition
reviewed the relationship between coffee consumption, obesity and type 2 diabetes. They concluded that there is mounting evidence of a reduced risk of developing type 2 diabetes among those who drink three to four cups of coffee a day.
“The effects are likely due to the presence of chlorogenic acid and caffeine, the two constituents of coffee in higher concentration after the roasting process,” they say.
A range of studies have variously found that coffee intake reduces the risk of liver damage in people at high risk of liver disease; reduces the risk of Alzheimer’s disease in regular coffee drinkers, compared with those who don’t drink coffee; and is inversely associated with the risk of Parkinson’s disease in men and in women who have never used post-menopausal oestrogen.
Although moderate caffeine intake (two to three cups of coffee or 300mg/day) is not associated with adverse health effects in healthy adults, coffee should not be freely drunk by everyone. A report in the International Journal of Cardiology earlier this year described a study of more than 1,200 patients, aged 18-45 years, with hypertension (high blood pressure) who were followed up for an average of 12 years.
The results indicated that those patients who drank coffee had a higher risk of developing adverse cardiovascular outcomes. The report concluded: “Hypertensive patients should be discouraged from drinking coffee.”
Since caffeine can cross the placenta, and because excessive caffeine intake has been implicated as a cause of spontaneous abortion, women who are pregnant or planning to become pregnant should be prudent in their coffee intake.
The ICC recommends “. . . that pregnant women limit their caffeine intake from all sources to 200mg per day in line with current guidelines”.
Athletic performance
Coffee is not only a socially acceptable beverage, it can improve athletic performance. “Research into the ergogenic properties of caffeine has revealed benefits across a range of exercise intensities and durations, with the greatest benefits being evident in sustained high-intensity aerobic activities,” says Dr
Mark Glaister
of St Mary’s University College, Twickenham.
“Indeed, caffeine doses of 3-6 mg/kg [equivalent to two to four cups of strong coffee] ingested 30-60 minutes prior to exercise have been shown to result in performance increases of up to 5 per cent in cycling time-trial events lasting five to 60 minutes.”
Coffee’s performance-enhancing effects are linked to caffeine’s interaction with the neurotransmitter adenosine, which can slow down neural activity, making you feel drowsy.
“The key mechanism by which caffeine is believed to exert its effect is by blocking adenosine receptors, leading to increases in neural transmission rates [increased muscle activation], and pain suppression,” says Glaister.
It’ll soon be time for my run, but first . . . barista, can I have a cappuccino, please?
