A warm cup of coffee is a part of daily routine for most people across the world. As daylight saving fights with our sleeping patterns, most of the folks in the U.S run to grab a cup of coffee to kill that drowsiness. However, in case of some individuals, even a small amount of caffeine is enough to keep them up during the night. Why is it that caffeine affects people in different ways? The answer lies in our genes. We have inbuilt genetic factors that enable us to self regulate our caffeine intake.
Regular coffee people will develop some tolerance towards caffeine consumption which can be reversed by giving up the daily cup. However, if you prefer to not consume coffee because it makes you sleepless or anxious, it probably has more to do with small variations in your DNA- A, G, C & T.
All depends upon your metabolism- how your body deals with caffeine floating around in the system- two genes handle most of the work. CYP1A2 produces liver enzymes that metabolize 95% of ingested caffeine. AHR controls how much enzymes you produce. Together these 2 genes define how much caffeine is circulated in your bloodstream & for how long. People who have gene variants that drive low caffeine metabolism will consume less coffee compared to those who have gene variants that promote increased caffeine metabolism.
If you are a quick metaboliser, you process caffeine at a much faster rate. As such, caffeine will not linger long enough to impact your brain stimulus centers. Caffeine can be consumed safely while providing beneficial antioxidant properties.
However, if you make less caffeine metabolising enzymes, more of the chemical will circulate in your body longer. Slow metabolizers may face negative impacts of caffeine consumption to a higher degree such as insomnia, upset stomach & anxiety. There is also a possibility of slow metabolizers suffering from a nonfatal heart attack due to high blood pressure as a result of high amount of caffeine intake.
A completely different set of genes are said to impact brain activity & reward centers as well as anxiety, insomnia & stomach upset. Adenosine, one of the reasons for morning dizziness & post lunch slump, slows down your nerve activity and prevents release of feel good factors including dopamine. However when caffeine is circulated in your bloodstream, it takes place of Adenosine in receptors in your brain & boosts your wakefulness.
Expression of Adenosine receptor is regulated by gene-ADORA2A. Variants of this gene influence your reaction to caffeine. This variant could be a reason why people have insomnia after having a sip early in the day or suffer from anxiety with consumption of as low as 150 mm of caffeine. Variation in Dopamine receptor gene DRD2 may also impact your caffeine consumption. Besides, the ABCG2 gene may impact how much caffeine reaches your nervous system.
It is important to note that besides genetics, interplay between genes & your lifestyle also impact your body’s ability to metabolise caffeine. Your diet, stress & sleep pattern also impact how your body will respond to caffeine.
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