Is coffee bad for you?

Here’s the thing. I love my morning cup of coffee. It doesn’t replace sleep or a healthy breakfast for energy, but it’s something I enjoy and don’t want to give up. But am I doing myself harm?

If you delve into the web, you’ll find coffee is blamed for sleepless nights, anxiety, cellulite and bad skin, which means most of us have attempted to crack our habit at one time or another. But is it really all that bad?

After looking into the evidence it’s time to set the record straight (spoiler alert – coffee isn’t bad. In fact, there are some surprising health benefits).

Coffee and mental performance 

Feel more awake after your coffee? No surprise. Caffeine improves alertness and ability to perform brain-taxing tasks by switching off a brain chemical which causes sleepiness. This means a cup of coffee before work is a good time to take advantage of those effects.

The other ideal time to benefit from coffee is pre-workout. A cup of coffee before you hit the gym or the great outdoors improves motor control and reduces your sensation of of pain and fatigue (which means you can push that bit harder). For athletes, it’s one of the only legal performance-enhancing aids – when caffeine is consumed pre-workout, subjects feel less tired and can exercise for longer. The benefits are noticeable at doses as low as 1mg per kg of body weight – a single shot of espresso contains around 100mg.

Coffee and the risk of diabetes and heart disease

It seems like an odd connection, but lots of studies show regular drinkers have a lower risk of diabetes. We don’t know why, but researchers think the effects are thanks to plant chemicals in coffee beans that help control blood glucose (sugar) levels.

After looking at the evidence, scientists at the Harvard School of Public Health also concluded 1-2 cups of coffee per day could lower the risk of heart disease.

Some of the benefits might be down to antioxidants. Although we usually think go fruits and vegetables as the best source of antioxidants, a 2005 study from the University of Scranton found coffee was the number one source of antioxidants in the U.S. diet. Antioxidants help protect us from disease by stopping our cells becoming damaged.

What about sleep, dehydration and anxiety?

It would be unfair to talk about the positives of caffeine without being honest about the effects of high intakes. Because caffeine is a stimulant, large intakes do mess with sleep patterns.

In a 2013 study scientists looked at the effect of a big cup of coffee consumed at bedtime, 3 hours before or 6 hours before sleep. They found caffeine reduced sleep time in every condition. We know that it takes around 6 hours for the caffeine in the blood to reduce by half, so if you want to get a peaceful night, stick to drinking it in the morning.

High intakes of caffeine can also trigger anxiety, particularly in those who are more at risk of suffering from depression. If you identify with this, it’s wise to be aware of the effect of high amounts of caffeine on your mood, and switch in more caffeine-free options.

As for fluid balance, research doesn’t support the theory that coffee makes us dehydrated. In one study published in the Journal of the American College Of Nutrition, regular coffee drinkers had the same levels of hydration as those who stuck to water.

It’s true caffeine is a diuretic (meaning it makes you produce pee a bit more), but the amount you lose is offset by the amount of liquid in a cup of coffee. The exception to this is espresso, so copy the Italians and serve espresso with a glass of water.

Bottom line A  coffee or two a day isn’t bad for you – in fact it can actually do you good. For maximum benefit (and to avoid sleepless nights) drink your coffee in the morning or before a workout.

NB. Women who are pregnant are advised to limit their caffeine intake to 200mg a day – the equivalent of two cups of instant coffee.