How much is too much?

Most of us like a nice cup of coffee and occasionally, before we know it, we can’t function without one. So, is it really all that bad? The answer – as a general rule is just like anything – in moderation no – coffee is fine, but (and there always seems to be a ‘but’!) we do need to be aware of consuming too much.

On average a regular cup of instant coffee contains approximately 70-100mg of caffeine, but this can be difficult to judge as caffeine content is not usually labelled and surprisingly high street coffee chains can range from 75mg to almost 400mg in one cup (alarmingly!) depending on the brand, size of cup and strength of the coffee.

As a general rule it is accepted that up to 400mg of caffeine per day is considered safe (approximately 4 cups of instant coffee). Unfortunately, our bodies are able to adapt to caffeine meaning that the body begins to get used to the effects and no longer feels awake and alert.  In order to replicate the ‘good feeling’ more caffeine is needed, thus building up a tolerance level and explains why, over a period of time, people can find themselves needing more and more caffeine to ‘get them through the day’

So how do you know if you are drinking too much? 

Apart from counting the number of cups of coffee you drink, if you regularly experience:

  • Increased heartburn
  • Headaches
  • Difficulty sleeping
  • Anxiety
  • Muscle cramps/tremors

This may be an indication that you are consuming too much caffeine, however, if you reduce or stop your caffeine intake and experience:

  • Headaches
  • Irritability
  • Lethargy
  • Muscle stiffness
  • Lack of concentration
  • Insomnia
  • Depression

These may well be symptoms of caffeine withdrawal and you must ensure that you reduce your caffeine intake gradually as stopping suddenly may cause further health problems.  Should you have any untoward symptoms ensure you contact your doctor.

Take heart – coffee isn’t all bad!

Affects of Coffee IntakeWith the above information it may seem that coffee is an absolute ‘no go’ and should be avoided at all costs. This is not the case as coffee does contain many nutrients which may be beneficial to the body. In fact, some studies have shown that consuming up to 300mg of caffeine can have favourable effects such as lowering the risks for Type II diabetes and reducing symptoms of Parkinson Disease.

All-in-all people should be aware and mindful of the disadvantages of caffeine and importantly be educated in the amount of caffeine contained within high street coffee, but this should not prevent them from enjoying it in moderation.


Alsene K. et al. (2003) Association between A2A receptor gene polymorphisms and caffeine-induced anxiety. Neuropsychopharmacology, 28(9):1694-702.

Postuma RB, Lang AE, Munhoz RP et al.  Caffeine for treatment of Parkinson disease: a randomised controlled trial. Neurology. 2012; 79 (7): 651-8

Ross GW, Abbott RD, Petrovitch H, et al. Association of Coffee and Caffeine Intake With the Risk of Parkinson Disease. JAMA. 2000; 283(20):2674–2679. doi:10.1001/jama.283.20.2674