Caffeine is a naturally occurring substance.
Caffeine is found in the leaves, seeds, and/or fruit of more than 60 plants1.
Caffeine belongs to a group of compounds called methylxanthines2, derived from purine, a nitrogenous base. Plants produce caffeine as a defense mechanism against insects and herbivores, as it can act as a neurotoxin and a repellent.
Some of the most common plants that contain caffeine are coffee, tea, cacao, guarana, and kola.
Caffeine is not only found in coffee and tea.
Caffeine is also present in energy drinks, sodas, chocolates, and medications.
Caffeine is added to enhance their flavor, appeal, and effectiveness.
The amount of caffeine in different products can vary widely, depending on the type, quality, and preparation method. Caffeine in these products can range from 1 to 100 mg per serving.
Caffeine is a natural stimulant.
Caffeine can affect the brain and the nervous system3. It can have various effects on the body and the mind, such as increasing alertness, energy, mood, and cognition and enhancing physical performance and endurance.
Caffeine can also have some adverse effects, such as causing anxiety, insomnia, headaches, heart problems, and stomach issues, especially when consumed in excess or by sensitive individuals4.
Caffeine is the fourth most widely used drug.
Caffeine ranks behind alcohol, tobacco, and marijuana as the most widely used drug.
According to the World Health Organization, about 90% of adults consume caffeine in some form4, and the global average intake is about 76 mg per person daily5.
The most common sources of dietary caffeine are coffee (64%), tea (18%), and soda (15%), which account for about 87% of global caffeine consumption6.
The maximum daily caffeine intake for adults is 400 mg7.
This equals about 4 cups of brewed coffee, ten cans of cola, or two energy-shot drinks.
However, the amount of caffeine safe for each person may vary depending on their age, weight, genes, health conditions, and sensitivity to caffeine.
Pregnant and breastfeeding women, children, and people with certain health conditions or medications should limit or avoid caffeine intake, as they may be more sensitive to its effects than healthy individuals.
Sources and References
- International Food Information Council. (2019, October 7). Natural vs. added caffeine: What’s the difference? [Blog post]. https://foodinsight.org/natural-vs-added-caffeine-whats-the-difference/
- Fredholm, B. B. (Ed.). (2020). Caffeine. In Encyclopedia of neuroscience (pp. 1-14). Academic Press. https://www.sciencedirect.com/referencework/9780323908160
- Nehlig, A. (2018). Caffeine and the central nervous system: Mechanisms of action, biochemical, metabolic and psychostimulant effects. In J. Preedy (Ed.), Coffee in health and disease prevention (pp. 191-204). Academic Press. https://www.ncbi.nlm.nih.gov/books/NBK519490/
- Meredith, S. E., Juliano, L. M., Hughes, J. R., & Griffiths, R. R. (2013). Caffeine Use Disorder: A Comprehensive Review and Research Agenda. Journal of caffeine research, 3(3), 114–130. https://doi.org/10.1089/jcr.2013.0016
- Rodak, K., Kokot, I., & Kratz, E. M. (2021). Caffeine as a Factor Influencing the Functioning of the Human Body-Friend or Foe?. Nutrients, 13(9), 3088. https://doi.org/10.3390/nu13093088
- Samoggia, A., & Rezzaghi, T. (2021). The Consumption of Caffeine-Containing Products to Enhance Sports Performance: An Application of an Extended Model of the Theory of Planned Behavior. Nutrients, 13(2), 344. https://doi.org/10.3390/nu13020344
- U.S. Food and Drug Administration. (2018, December 12). Spilling the beans: How much caffeine is too much?. https://www.fda.gov/consumers/consumer-updates/spilling-beans-how-much-caffeine-too-much