Large-scale study shows drinking coffee lowers the risk of dying as well as improving your memory
I don’t know about you, but a nice cup of coffee jump-starts the day for me — and I’m not alone. Coffee is the world’s most widely consumed psychoactive substance, meaning a substance that has an effect on your brain. Coffee is a stimulant, making us more alert. It’s why we drink it, although some of us drink it because we like the flavour.
The global coffee shop industry is estimated at €170bn, bigger than any other sector in catering, even McDonald’s. In the US and Europe, around one billion cups of coffee are drunk every day. If an alien came to Earth and observed us, they might well conclude that we are slaves to the brown liquid, given the amount of it we consume.
Coffee has been in the news a lot recently. First, there are warnings that the cost of your cup of coffee is about to go up a lot. According to the IMF, there’s been a seven-fold increase in the cost of shipping a container across the oceans in the 18 months since March 2020, mainly because of increasing energy costs but also supply chain issues. This will impact on many imported goods.
As coffee must be shipped from countries like Brazil and Colombia, this increase is translating into higher coffee prices. Higher energy prices also increase the cost of roasting beans and add to the cost of transporting coffee to shops. Coffee prices jumped by almost 3pc between March and April this year in Ireland and are likely to increase further in the coming months.
And then there’s the issue of disposable coffee cups. Ireland has set itself the target of being the first country in the world to eliminate their use, just like we did with plastic bags.
According to the Government, nearly half a million cups are currently sent to landfill or incineration every day, which amounts to 200 million cups a year. That’s an awful lot of cups. We’ve got the coffee habit bad.
Even though many of us are still working from home, morning in every city sees people walking around holding coffee cups in their hands on their way to the office. That alien would think they are extensions of our hands, given how common this is.
The ban will begin over the coming months, for customers who have their coffee in cafes and restaurants.
A small charge on disposable cups for takeaway coffees will be next — just as happened with the levy on plastic bags. The Government wants you to bring your own reusable cup to your favourite coffee shop and fill it up. Or buy a non-disposable coffee cup in the shop, adding further to the cost.
All of this means that we’d better have a good reason for drinking coffee. In the past week some striking science has emerged — and the news is good. It should reassure you that drinking a couple of cups of coffee a day is very good for you.
We’ve known for some time that caffeine, the key ingredient in coffee, works by blocking something called adenosine in your brain. Adenosine makes us feel sleepy. It is higher in the morning and in the early afternoon. Blocking it with caffeine therefore wakes us up.
Caffeine probably evolved in the coffee plant as an insecticide. Coffee will repel mosquitoes, especially if you burn it or burn the coffee grounds. They hate the smell of it. As well as a way to repel insects, coffee can be used as a fertiliser. It attracts worms who, like us, love coffee. This is good news for your garden as worms are critical to keep the soil tilled and fertile.
Apart from keeping you alert, what does coffee do for you? Studies have shown that coffee lowers the risk of Parkinson’s disease, heart disease a Type 2 diabetes, as well as liver and prostate cancers.
And now the news comes that coffee drinking lowers the risk of dying. Pretty important. Researchers studied more than 170,000 people between the ages of 37 and 73 over a follow-up period of seven years. It’s a huge number and so the results are likely to be reliable.
Those who drank up to three cups of coffee per day, even with a teaspoon of sugar, were up to 30pc less likely to die during the study period. This was especially the case if the coffee had a spoon of sugar in it, so don’t feel guilty about that. But those who drank unsweetened coffee were also 16 to 21pc less likely to die during the study period.
There was also a lower chance of dying for people who drank decaffeinated coffee, possibly suggesting it was something other than caffeine that was responsible for prolonging life, although decaffeinated coffee will contain some caffeine. The study also showed the benefits of coffee went away for people who drank more than 4.5 cups of coffee each day. As with most things we like, moderation is the key here.
It’s being seen as an important study since there are very few things that reduce your risk of dying by 30pc.
It’s still not known what’s in coffee that brings these benefits. Coffee contains antioxidants, which can protect cells in your body from damage caused by naturally made chemicals called free radicals. Free radicals are what causes iron to rust and are made from oxygen. We make them, and we make more of them as we age. It’s a bit like coffee is acting as a paint to prevent rust, only in this case it’s preventing you from rusting.
One question is whether coffee can disrupt our sleep. When scientists examined that, they got a surprising result. Coffee drinkers didn’t have disrupted sleep, probably because the natural substances that trigger sleep, such as melatonin, overcome the effect of the caffeine. The study showed that the depth of sleep was equal, regardless of whether people had taken caffeine or a placebo. So don’t refuse a cup of coffee in the evening after dinner if you feel like it.
In another study, physical changes to the brain were observed. Coffee drinkers were found to have changes consistent with increased alertness. They also have changes in a part of the brain called the hippocampus. This is where memories are processed and stored, providing further evidence that coffee can improve memory.
But it’s not all good. Too much coffee increases stress levels and increased frequency of caffeine consumption was linked to increased anxiety, especially in males.
But if you want to remember something, say before an exam, drink a cup of coffee. It will do your hippocampus the world of good and might even prolong your life. The extra cost of a cup of coffee might therefore be well worth it, and if you use a reusable cup, you’ll be doing the right thing by the environment too.
Comedian Jerry Seinfeld got it right when he said: “We want to do a lot of stuff; we’re not in great shape. We didn’t get a good night’s sleep. We’re a little depressed. Coffee solves all these problems in one delightful little cup.”
Luke O’Neill is professor of biochemistry in the school of biochemistry and immunology at Trinity College Dublin