When you get your caffeine fix do you feel jittery, on-edge, or maybe you just don’t get the ‘buzz’? The way that your body responds to the effects of caffeine might lie in your genetics. Knowing what’s in your DNA may help you decide whether to finish off your evening meal with a cappuccino or just an after-dinner mint …
On average in the UK, we drink nearly 123 million cups of tea and 90 million cups of coffee per day. The morning brew is somewhat of an institution for us Brits – it wakes us up in the morning and keeps us alert throughout the day. The effects of caffeine can improve our focus and concentration so that we can be more productive and ready for the daily ‘grind!’
As well as tea and coffee, it’s particularly prevalent in popular fizzy drinks like cola, energy drinks and chocolate – so most of us will end up having some amount of caffeine each day. That caffeine ‘hit’ can be addictive, but the effects of caffeine can also leave us feeling less than perky so it’s good to keep a check-up on your caffeine intake and understand how your body reacts to caffeine.
Caffeine – how much is too much?
Do you find yourself regularly having mugs of strong coffee? Maybe you prefer drinking sugary energy drinks … Whatever your preferred caffeine source, how much you consume can be directly linked to your genetic makeup. In a large study into DNA and coffee drinking, people with a certain version of the CYPIA1 gene drank an extra 0.25 cups a day than the average.
What you especially need to keep an eye on is whether your DNA indicates a tendency to consume higher than average amounts of caffeine. If you’ve got the TT genotype, you’re likely to opt for a highly caffeinated drink more often than others.
For more details on caffeine sources, the potential benefits and possible risks, check out our caffeine guide.
Caffeine and your metabolism – why we have different reactions to the effects of caffeine
How your body breaks down caffeine determines your caffeine metabolism. When you have coffee, tea or an energy drink, the caffeine is processed by an enzyme in the liver. Variations in the CYP1A2 gene cause different levels of enzyme activity – but what are the consequences of having different metabolic speeds when it comes to caffeine?
Fast caffeine metabolism
If you’ve got the AA genotype, your body will likely metabolise caffeine faster than others. Fast metabolisers tend to be less sensitive to its typical effects – you might experience less caffeine-related sleep disruption, because the stimulant effects of caffeine may be shortened for you.
It’s important to understand whether you’re a fast metaboliser, as you may drink more and more caffeine in order to maintain that ‘coffee buzz’ over a long time. This could mean you’ll end up drinking more than is healthy for you.
Slow caffeine metabolism
Having either the AC or CC genotype means that you’ve probably got slow caffeine metabolism. The enzyme that metabolises caffeine doesn’t work properly in some people, so they’ll have to adapt their daily dose of coffee to ensure they don’t suffer from the negative effects of caffeine.
After drinking the exact same amount as others, slower metabolisers might get the jitters and feel anxious. It’s especially important for these people to monitor their caffeine intake, because they’ll suffer from more sleep disturbances like insomnia.
If you’re having difficulty sleeping,it may be wise to limit caffeine to the mornings because you may be sensitive to it. As a general rule, you could restrict caffeine after 2pm and have decaffeinated coffee, herbal teas or water instead and see how you feel. You may even wish to explore cutting caffeine out earlier. Experiment and see how you react.
Reviewed by:
Dr Brian Fisher MBBch MBE MSc FRSA – Clinical Director
Anna Keeble MA BA Head of Content and Wellbeing Expert
