Caffeine is undoubtedly one of the world’s most widely used stimulant due to its stimulating effects on the central nervous system. According to the US Department of Agriculture, world coffee production for 2018/19 is forecast 11.4 million bags higher than the previous year at a record 171.2 million (1). Caffeine is a naturally occurring substance found in the leaves and seeds of many plants, including coffee beans, tea leaves, and cocoa nuts. It is also produced artificially and added to some food and beverages for flavor.
Research suggests there are many potential benefits associated with caffeine. Moderate coffee consumption (3 to 5 cups per day) (2), for example, may help protect against several chronic diseases, including type 2 diabetes and liver disease(3,4,5). Coffee, dark chocolate and tea (especially green tea) all contain caffeine and are loaded with antioxidants and nutrients that can greatly benefit the body.
How Our Genes Play a Role
Although caffeine has been shown to be beneficial, not all people react to caffeine in the same way. For individuals with a genetic predisposition towards being slow caffeine metabolizers, caffeine has the potential to build up in the bloodstream and, as a result, may do more harm than good. Here’s why:
CYP1A2 is the key liver enzyme (special proteins that breakdown and use other substances) responsible for metabolizing caffeine. Variations in the CYP1A2 gene have a big impact on how caffeine affects our bodies. Therefore, you may be a fast or slow caffeine metabolizer based on your CYP1A2 genetics.
If you are a Slow Metabolizer then your genetic makeup indicates you process caffeine at a slower rate and, as a result, caffeine may have longer-lasting stimulant effects. Slow metabolizers may experience negative side effects of caffeine consumption to a higher degree such as insomnia, anxiety, and upset stomach. There is also evidence linking slow metabolizers with an increased risk of having a nonfatal heart attack and/or high blood pressure with higher amounts of coffee intake(6,7). To reduce the risk of potentially serious health complications, slow metabolizers may need to limit or avoid caffeine based on their body’s individual response.
On the other hand, if you are a Fast Metabolizer, you process caffeine at a more rapid rate and, hence, caffeine might not have as great or as lasting of an effect. For fast metabolizers, coffee (independent of other risk factors) will not increase the risk of heart attack and hypertension, therefore coffee can be safely consumed while providing beneficial antioxidants and bioactive properties.
It is important to note that in addition to your genetics, your body’s ability to metabolize caffeine also depends on many lifestyle factors. For example, your diet, stress levels, sleep, or activity level, can impact how you respond to caffeine. How much coffee you drink, the time of day, whether you smoke, or whether you take hormonal birth control may also play a role. In other words, some people may still be adversely affected by caffeine regardless of genetics.
If you are curious or concerned about how your own body reacts to caffeine, it may be beneficial to run a genetic test. By knowing your genetic type, you can adjust your daily caffeine intake accordingly and better manage your overall well-being. Because when it comes to caffeine, what works for one person doesn’t always work for another.
- United States Department of Agriculture. Coffee: World Markets and Trade. (2018).
- Toner, C. A Deep Dive on the 2015-2020 Dietary Guideline’s Inclusion of Caffeine. (Food Insight 2017).
- Jiang, X., Zhang, D. & Jiang, W. Coffee and caffeine intake and incidence of type 2 diabetes mellitus: a meta-analysis of prospective studies. Eur J Nutr 53, 25-38 (2014).
- Lee, J.H., Oh, M.K., Lim, J.T., Kim, H.G. & Lee, W.J. Effect of Coffee Consumption on the Progression of Type 2 Diabetes Mellitus among Prediabetic Individuals. Korean J Fam Med 37, 7-13 (2016).
- Wadhawan, M. & Anand, A.C. Coffee and Liver Disease. J Clin Exp Hepatol 6, 40-6 (2016).
- Cornelis, M.C., El-Sohemy, A., Kabagambe, E.K. & Campos, H. Coffee, CYP1A2 genotype, and risk of myocardial infarction. JAMA 295, 1135-41 (2006).
- Palatini, P. et al. CYP1A2 genotype modifies the association between coffee intake and the risk of hypertension. J Hypertens 27, 1594-601 (2009).