For many of us, the idea of getting through the afternoon slump at work without a cup of coffee doesn’t bear thinking about – but is our coffee habit damaging our health? For the 80% of UK adults who enjoy a cup of tea or coffee every day, it is certainly a question worth considering.
There are many different opinions regarding caffeine consumption, but the overriding theme is that, in moderation, it is fine. In fact, if you stick to the recommended guidelines, it can be good for you.
About 45 minutes after your first sip of coffee, the caffeine will have been absorbed by your small intestines and will start to enter your bloodstream. From here, some of the caffeine goes to the liver to be metabolised into other chemicals and the rest remains unaltered in your blood. Together with the chemicals produced by your liver, this caffeine heads to your brain.
The key function of caffeine is to block a chemical called adenosine, which essentially works to slow down and dampen brain activity. Caffeine stops this from happening, resulting in a positive build-up of energy-promoting processes that produces adrenaline and boosts metabolism.
Once you have finished your cup, the caffeine will have made you feel more awake, more alert and more attentive. This effect will last from three to five hours.
As well as boosting mental prowess, caffeine also promotes physical performance. One of the active chemicals that is created when the liver metabolises caffeine is called paraxantine, and this helps your body to break down fats in a process called lipolysis. This results in your body using more fat for energy, preserving glycogen reserves for your muscles.
When does it become harmful?
Current guidelines advise people not to exceed 400mg of caffeine a day, this equates to around four cups of instant coffee. Pregnant women are the exception however, they can only have half of this a day. Once you start exceeding this amount, you may find yourself running into trouble. Depending on the amount you have consumed, too much caffeine can cause you to urinate more frequently, give you heart palpitations, raise your blood pressure or even develop a tremor.
Going completely overboard on caffeine can result in caffeine toxicity, which can cause insomnia and cardiac abnormalities.
Tips for monitoring your consumption
Keep a note of all caffeine you consume, this includes tea, coffee, chocolate, Coca-Cola and even painkillers. If you find yourself nearing the 400mg mark, swap your next coffee for a herbal tea instead.