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Let’s Talk about Caffeine…

-By Dr Rosamund Yoxall BMBS BSc, Nutrition & Functional Medicine specialist at the HealthHub

There is something inherently lovely about wrapping your hands around a steaming mug of deeply dark coffee on these cold autumnal mornings, or sharing a cup of tea and a catch up with an old friend. But does the caffeine that lurks within these warming drinks have any health effects we should know about? 

Whilst there is no ‘right’ or ‘wrong’ in nutrition (and I am certainly not suggesting you give up your beloved coffee machine!), arming yourself with some knowledge of the underlying nutritional science enables you to make an informed decision about the food and drinks you enjoy.  That is certainly my aim with all of my clients, and I hope I can share a little of this knowledge with you here too.

What is caffeine?

Caffeine is a naturally occurring plant compound, which is thought to function for the plant as an insect repellant and herbicide (Wikoff et al., 2017).  In humans, it is the most commonly consumed stimulant worldwide, and is well known for its effects on our wakefulness, focus and concentration.

Once ingested, caffeine is rapidly absorbed into our bloodstream, and starts to have an effect just 15 – 20 minutes later. How long those stimulatory effects last varies significantly from person to person, but can be anywhere between 2-8 hours. 

How much caffeine is in my diet?

Drink Approximate caffeine per serving
Mug of filter coffee 90 – 140mg
Mug of instant coffee 60-100mg
Single Espresso (60ml) 80mg
Mug of black tea 50 – 75mg
340ml Coca-cola / diet coke 35 – 45mg
50g dark chocolate 20-35mg
Mug of cocoa 15mg
Green tea 15mg

What are the health benefits of caffeine?

The good news first! Beyond the obvious benefits that caffeine can have in terms of pleasure (there is often an enjoyable ritual in making and drinking a cup of tea or coffee), helping us to get going in the morning, maintaining focus and concentration at work, or keeping us wide awake on late-night drives, caffeine can also come with other health benefits. 

Caffeine-containing drinks, including coffee, black tea, green tea and even cocoa also contain relatively high amounts of health-boosting polyphenols.

Polyphenols are a class of beneficial antioxidants, and are found in particularly high concentrations in brightly coloured fruits and vegetables, tea, coffee, dark chocolate and red wine. They are thought to play a role in the prevention of some cardiovascular disease, neurological diseases and even diabetes (Scalbert et al., 2005). In particular, caffeine consumption has been linked to a decreased risk of Parkinson’s disease (Costa et al., 2010), whilst green tea consumption may be beneficial for reducing heart disease and stroke risk (Pang et al., 2016).

Caffeine can also be beneficial to support sports performance, by reducing perceived fatigue (Doherty and Smith, 2005) and potentially increasing muscle power output. This is often used to athletic advantage, as sports gels frequently contain the same amount of caffeine as large a mug of coffee!

A little known fact…

Consuming a dose of caffeine of around 100mg (the equivalent of a mug of coffee or a couple of mugs of tea) alongside standard pain killers (such as paractemaol and ibuprofen) may give slightly better relief for acute pain in adults than taking the tablets without caffeine. Whilst of course, it is not a good idea to rely on this as a strategy to help with chronic or long term pain, it may be useful to know if you need to take a couple of painkillers from time to time.

For more information on this effect, take a look at this online article: http://www.cochrane.org/CD009281/SYMPT_caffeine-analgesic-adjuvant-acute-pain-adults

What are the potential downsides of caffeine?

Alongside these potential benefits, there are also certain situations where caffeine can be detrimental to our health. Below is a list of a few of the key times when being conscious of your caffeine consumption may be beneficial;

  • If you are planning pregnancy or are currently pregnant, national guidelines recommend that you avoid consuming more than 200mg caffeine per day, as it may increase the risk of miscarriage, or of having a baby with a low birth weight.

For more information on this; https://www.nhs.uk/chq/Pages/limit-caffeine-during-pregnancy.aspx

  • If you suffer from anxiety, the physical symptoms of caffeine consumption (such as nervousness, irritability or stomach upsets) can sometimes make your worry feel worse. Caffeine can also stimulate adrenaline and noradrenaline hormone release – which is the last thing you want if you are already feeling stressed and anxious! It may be better to cut right down on caffeine in these instances.
  • Excessive caffeine consumption can, in some cases, lead to palpitations and ‘ectopic’ heart beats (the feeling of your heart beating in your chest). It is always important to discuss any symptoms like these with a doctor in the first instance, but you may find that you are encouraged to moderate your caffeine as part of your management plan.

For more information on this; https://www.nhs.uk/conditions/heart-palpitations/

  • If you suffer from insomnia or sleeping difficulties, you are probably already being mindful of minimisng your evening caffeine intake. But any caffeine consumption, even first thing in the morning, could still be having an impact. So if you are struggling with your sleep, why not try cutting down (or even cutting out) caffeine completely for a few weeks to see if this makes a difference?
  • Habitual caffeine consumption leads to a certain amount of tolerance; you end up needing a bigger ‘hit’ to get the same energising effects. This can be a particularly vicious circle for those suffering from fatigue; the more tired you feel, the more you reach for a caffeine boost – which eventually increases your tolerance and means you need even more caffeine to feel ‘normal’.

If you suffer from fatigue that is impacting your daily life, it is always worth discussing this with a qualified healthcare professional to see if there is any underlying cause that needs addressing.

  • Caffeine intake may also increase blood pressure slightly (although potentially less so when consumed as coffee than from other sources) (Noordzji et al., 2005). If you suffer from high blood pressure, it may therefore be worthwhile sticking to moderate amounts of caffeine (approximately 200-300mg/day).
  • If you suffer from osteoporosis, or are considered to be at risk of developing weak bones, it may also be sensible to limit the amount of caffeine you consume, as it can potentially interfere with calcium absorption and excretion, particularly at higher doses (Wikoff et al., 2017).  Again, stick to a sensible and moderate amount if necessary, and do make sure you are consuming plenty of sources of calcium in your diet too.

A word of warning on cutting down your caffeine consumption…

If you suffer from migraines or frequent headaches, abruptly cutting out your caffeine can cause uncomfortable rebound headaches to occur.

It is therefore usually best to cut down your consumption slowly in these instances (by around 1 cup per week), and support your diet in other ways to help minimise these unwanted side effects. 

Taking things slowly when it comes to reducing caffeine consumption tends to be a better option for most of my clients; even if you do not suffer from frequent headaches, abrupt withdrawal from caffeine can cause them anyway.

The bottom line?

  1. Moderation is key; 1-2 cups of coffee or 2-3 cups of tea (ideally including some green tea) a day is a sensible amount of caffeine intake for most people (without added sugar!)
  1. For some people, however, cutting out caffeine completely may be appropriate. I usually recommend that this is done slowly over time. If you are not sure whether or not this is a good idea for you, please feel free to book an appointment with me to discuss your personal concerns in more detail.
  1. If you love the taste of tea and coffee but would still like to cut down on your caffeine consumption, do try to look out for organic decaffeinated versions. Clipper does the best decaf tea I have personally tasted!
  1. Avoid caffeinated ‘energy drinks’ where possible. These often contain significant amounts of sugar, sweeteners and other ingredients as well as potentially excessively high doses of caffeine.
  1. However, as with all things nutrition-related, there are no hard and fast rules. What is right for one person may not be appropriate for the next. If in doubt, it is always best to seek professional advice.

For more information;

This fact sheet on Caffeine is produced by the European Food Standards Agency and is a treasure trove of information;


If you are interested in understanding more about how your lifestyle and nutritional choices may be affecting your health, drop me an email [info@sagehealthnutrition.com] to arrange an initial consultation.

For more information on me and my services; www.sagehealthnutrition.com


Costa J., Lunet N., Santos C., Santos J., Vaz-Carneiro A. (2010) Caffeine Exposure and the Risk of Parkinson’s Disease: A Systematic Review and Meta-Analysis of Observational Studies, Journal of Alzheimer’s Disease, 20(1); S221-S238

Doherty M. and Smith P. (2005) Effects of caffeine ingestion on rating of perceived exertion during and after exercise: a meta-analysis, Scandinavian Journal of Medicine & Science in Sports, 15 (2); 69-78

Noordzij M., Uiterwaal S, Arends LR, Kok FJ, Grobbee DE, Geleijnse JM. (2005) Blood pressure response to chronic intake of coffee and caffeine: a meta-analysis of randomized controlled trials. Journal of Hypertension, 23(5); 921-928

Pang, J., Zhang, Z., Zheng, T., Bassig, B.A., Mao, C. and Liu, X. (2016) ‘Green tea

consumption and risk of cardiovascular and ischemic related diseases: A meta-analysis’, International Journal of Cardiology, 202, pp. 967–974.

Scalbert A., Manach C., Morand C., Remesy C., Jimenez L., (2005) Dietary polyphenols and the prevention of diseases. Critical Reviews in Food Science and Nutrition 45 (4): 287-306

Wikoff D., et al. (2017) Systematic review of the potential adverse effects of caffeine consumption in healthy adults, pregnant women, adolescents, and children, Food and Chemical Toxicology, 109(1); 585-648.