This article was first published in 听
Obviously, the expression 鈥渁 cup of joe鈥� has some interest for me.
One theory alleges the term derives from the ban imposed by Admiral Josephus 鈥淛oe鈥� Daniels, Secretary of the Navy, on serving alcohol aboard U.S. Navy ships. If the men couldn鈥檛 drink alcohol, they drank coffee and called it 鈥淛oe鈥� in reference to the admiral. But there is a problem here. The edict banning alcohol was issued in 1914 and the first time the expression 鈥渃up of joe鈥� appears in any written record is in 1930. 鈥淛oe鈥� probably derives from a slurring of 鈥渏amoke,鈥� a blending of the name of the island of Java and the city of Mocha in Yemen where coffee beans were traditionally grown and combined by traders to produce a flavourful brew. Maybe.
A more significant question than the origin of 鈥渃up of joe鈥� is the effect that cup has on our health. Given that two-thirds of adults in North America drink coffee daily, averaging three cups, that question begs for an answer. So, is coffee good for us or bad? It all depends on which studies we look at and, of course, on the amount consumed.
A paper published in the European Journal of Preventive Cardiology in 2022 examined data compiled by the U.K. Biobank study that surveyed half-a-million people between the ages of 40 and 69 about their coffee-drinking habits. Although dietary surveys are notorious for inaccurate reporting, people are likely to know how many cups of coffee they consume a day.
The subjects were followed for 12.5 years during which time 6.2 per cent of participants died. But those who drank coffee were less likely to die from any cause, no matter whether they drank ground, decaffeinated or instant, with the greatest reductions seen with two to three cups a day. The largest reduction was 27 per cent for ground, followed by 14 per cent for decaf and 11 per cent for instant. There was also a decrease in the onset of cardiovascular disease, which encompasses coronary artery disease, congestive heart failure and stroke. Again, the lowest risk was with two to three cups a day with ground coffee leading the way with a 20-per-cent reduction, followed by instant with nine per cent and decaf at six per cent. Even arrhythmias were reduced, albeit not by decaffeinated coffee. Ground coffee and instant coffee reduced risk by 17 per cent and 12 per cent, respectively.
Exactly what components in coffee are responsible for the noted effect is not known, but coffee contains a variety of antioxidants in the polyphenol category as well as melanoidins formed during the roasting of coffee beans. Indeed, coffee is the major source of antioxidants in the North American diet.
The Biobank study also revealed a J-shaped association between coffee consumption and both depression and anxiety, with the lowest risk of the mental disorders occurring at around two to three cups per day. Less had no effect and more had a negative effect. This was supported by another study of 14,413 Spanish university graduates that found a lower risk among participants who drank about four cups a day when compared with those who drank less than one. A Korean study of 10,000 adults found that more than two cups a day reduced the risk of depression. Why coffee should have an antidepressant effect is not clear, but one suggestion is that polyphenols found in coffee can be converted by gut bacteria into neurotransmitters such as serotonin that can cross the blood-brain barrier and have a mood-elevating effect.
There鈥檚 more. A group of Australian researchers subjected 227 seniors to a battery of cognitive tests and a subset of this population underwent brain scans to detect amyloid protein deposition in the brain, a hallmark of Alzheimer鈥檚 disease. Greater coffee consumption was associated with a lower likelihood of transition to cognitive impairment as well as reduced amyloid accumulation over the 10 years of the study. For almost 30 years, a Finnish study followed thousands of individuals who had filled out questionnaires about their eating habits and health status and found that the lowest risk of developing Alzheimer鈥檚 disease was among those who drank three to five cups of coffee a day. Other studies have shown an inverse association of coffee consumption and Type 2 diabetes as well as Parkinson鈥檚 disease. And for some more good news, a Swedish study of some 300 women has shown that three cups of coffee a day reduces the risk of breast cancer.
Now for the downside. Worries about the carcinogen acrylamide formed during the roasting of the beans are unfounded. The amounts detected are too small to be of consequence. In some people, caffeine can cause restlessness, insomnia and feelings of anxiety. The solution here is simple. Avoid coffee or stick to decaf. While coffee may momentarily elevate blood pressure, it has minimal effect on long-term blood pressure control. Nevertheless, sometimes scary headlines do appear. 鈥淎 single espresso a day can damage your heart.鈥� 鈥淥ne caffeine-packed cup can slow blood flow to the heart by 22%.鈥� Whoa! Those are headlines that can make your heart skip a beat. They come from British newspapers reporting on an Italian study about the effects of a cup of espresso on blood flow and blood pressure.
Researchers enlisted 10 healthy males and 10 healthy females to drink either a cup of espresso or a cup of decaf and have their blood pressure and arterial response be monitored. In the latter case, the technique is to cut off the blood supply in an arm and then using ultrasound, measure how effectively the brachial artery, the main artery in the arm, dilates when blood flow is restored. If the artery doesn鈥檛 dilate effectively, it means that blood flow is impaired, which is a possible sign of atherosclerosis in the making.
There was a 22-per-cent greater dilation after the decaf, inspiring the headlines about damaging the heart and reducing blood flow to the heart by 22 per cent. As far as blood pressure goes, there was a small increase, but essentially within the scope of experimental error. Twenty subjects make for a small sample size and measurements were taken only 30 and 60 minutes after drinking the coffee, so the longevity of the vasoconstriction effect is unknown. Most important, short term constriction of the arteries may have no clinical significance since arteries constrict and dilate throughout the day in response to activity.
Contrary to the implication inherent in the headlines, this Italian study does not show that a single cup of espresso damages the heart. Indeed, there is overwhelming evidence that the three 鈥渃ups of joe鈥� consumed by the average Joe is safe and may even be beneficial.
