Coffee and Your Health: The Good and the Bad

Coffee – it’s the world’s most consumed beverage (after water), with the planet slurping two billion cups a day. But how healthy is all that caffeine? Surely nothing that addictive could be good for us?

Turns out, it might be – and it doesn’t seem to be incurring any significant harm either. That’s according to a significant pile of research into the health effects of caffeine, which has been conducted over decades. We break down some of the key, recent findings below.

The good

You might suppose that, given what a few espressos can do to your heart rate, caffeine’s effect on the organ may be unsavory. But plenty of studies have actually demonstrated cardiac benefits.

Research by University of Bologna scientists, published last year, observed that Italians who drank one-to-three cups of coffee per day had lower systolic and pulse pressure than those who didn’t drink any coffee. The caffeine sippers also had lower peripheral and central aortic pressure.

Another observational study found that people who reported drinking 1 or more cups of coffee per day had a lower risk of long-term heart failure (5-12% per cup per day of coffee) than their caffeine-free counterparts. Interestingly, the risk of heart failure didn’t change between 0 to 1 cup per day, but was about 30% lower in people who drank at least 2 cups a day.

Other reviews and meta-analyses also concluded that habitual consumption of 3-5 cups of coffee per day is associated with a 15% reduction in the risk of cardiovascular disease, and higher consumption isn’t linked to an elevated risk.

Even those who drink up to 25 cups a day (yes, you read that right) do not seem to be at risk from major cardiac issues. Research from the British Heart Foundation published back in 2019 found that participants were no more likely to have arterial stiffness if they consumed two dozen coffees a day. The study also found that drinking a cup of coffee can stimulate the body’s brown adipose tissue, which generates body heat by burning calories.

Other studies into obesity have found evidence that a mug of java may even help keep the waistline in check.

People carrying genes that slowed their coffee metabolism down were associated with having a lower bodyweight, body fat levels and also a lower risk of developing type 2 diabetes, in a 2023 study. The researchers therefore concluded that high blood caffeine levels may curb body fat.

A daily cuppa may also benefit the brain. In one recent preliminary in vitro laboratory test, espresso compounds were observed to inhibit tau protein aggregation — a process believed to be involved in the onset of Alzheimer’s disease.

Another study from last year found a positive link between coffee (and tea) consumption and the thickness of the macular retinal nerve fiber layer – the thin layer of nerve cells that transmit visual information from the eye to the brain.

Down in the liver, caffeine also appears to help keep some hepatic diseases at bay. Back in 2015, a meta-analysis of 16 studies indicated that coffee consumption can significantly reduce the risk for hepatic fibrosis and cirrhosis. Why? The researchers posited that the energizing compound could downregulate the expression of α-smooth muscle actin and procollagen, promoting liver healing. 

Irrespective of any of these potential health boons, a cup of coffee may just make you a bit more pleasant in the morning. One social study found that people gave more positive reviews for their group’s performance on a task – and their own contribution – if they drank coffee beforehand.

The less good

However, this mood-enhancing quality of caffeine’s may just be the relief from caffeine withdrawal, which can cause headaches and irritability. Compensate too much for this withdrawal, though, and one can feel the negative effects of caffeine over-consumption, such as anxiety and headaches.

These effects are more consequential for certain people. Those with panic disorders, for instance, are likely to have a panic attack if they consume five or more coffees a day, according to one systematic review, and those who already live with insomnia are likely to have a long night if they drink before bed.

In rare cases, high caffeine consumption can lead to a caffeine overdose. In one case study, a university student ended up in a hospital emergency department, presenting with nausea, palpitations and vomiting, after taking a caffeine energy supplement that amounted to 6,000 milligrams (mg) of caffeine – about 60 times the typical levels found in a mug of brewed coffee.

In lower, regular doses, though, caffeine doesn’t seem to be tied to any long-term, cumulative health defects, unlike many other recreational drugs (alcohol, tobacco, etc.).

This safety certificate isn’t quite extended to the unborn, however. High caffeine levels during pregnancy had been linked to miscarriages and low birth weights, which is why many national health agencies recommend a pregnancy-caffeine limit of 200 mg per day. A 2020 review published in the British Medical Journal even went as far as to say there is “no safe level of caffeine consumption for pregnant women and would-be mothers”.

Conclusion

Caffeine is undoubtedly one of the safest recreational drugs there is. Although it has its detriments when consumed in excess, anyone not pregnant should be able to enjoy the revitalizing taste of coffee without much concern for their health.