Busting 3 Common Coffee Myths with Science
Coffee is a daily ritual for millions of people, but myths about its effects have been circulating for decades. From health concerns to caffeine misconceptions, it is time to separate fact from fiction. Here are five of the most common coffee myths, backed by science.
1. Dark Roast Has More Caffeine
Myth: Dark roast coffee is stronger and therefore contains more caffeine.
Reality: Roast level affects flavour more than caffeine. Research from the Institute of Food Science in Europe shows that lighter roasts generally retain slightly more caffeine than darker roasts because the roasting process breaks down caffeine compounds over time. So while dark roast tastes bold, it does not pack more caffeine than a medium or light roast.
2. Coffee Dehydrates You
Myth: Because caffeine is a diuretic, drinking coffee will dehydrate you.
Reality: Multiple studies, including research from the University of Birmingham in the UK, show that moderate coffee consumption contributes to your daily fluid intake in the same way as water. While caffeine can have a mild diuretic effect, the water content in coffee offsets this. For regular coffee drinkers, the body adapts, making the effect even less significant. Coffee can be part of healthy hydration when consumed in moderation.
3. Coffee Stunts Your Growth
Myth: Drinking coffee as a teenager will make you shorter.
Reality: There is no scientific evidence to support this claim. Medical research globally has found no link between coffee consumption and bone development or growth in children or adolescents. This myth likely originated from early concerns about coffee and calcium absorption, which have since been disproven. The real concern for younger people is overconsumption of caffeine, which can affect sleep, but growth is not impacted.
THE bottom line
Most coffee myths are based on outdated research or misconceptions. Current evidence shows that coffee, when consumed in moderation, can be part of a healthy lifestyle. It does not stunt growth, it does not dehydrate you, and for most people, it does not harm the heart.
So enjoy your coffee with confidence, knowing that science is on your side.
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References
1. Poole, R., Kennedy, O. J., Roderick, P., Fallowfield, J. A., Hayes, P. C., & Parkes, J. (2017). Coffee consumption and health: Umbrella review of meta-analyses of multiple health outcomes. BMJ, 359, j5024. https://doi.org/10.1136/bmj.j5024
2. Loftfield, E., et al. (2022). Light-to-moderate coffee consumption associated with cardiovascular health benefits. Queen Mary University of London / UK Biobank Study. https://www.qmul.ac.uk/media/news/2022/smd/new-study-shows-light-to-moderate-coffee-consumption-is-associated-with-health-benefits-.html
3. Ding, M., Satija, A., Bhupathiraju, S. N., et al. (2022). Coffee consumption and risk of cardiovascular diseases and mortality. Monash University, Australia. https://research.monash.edu/en/publications/coffee-and-tea-on-cardiovascular-disease-cvd-prevention
4. Killer, S. C., Blannin, A. K., & Jeukendrup, A. E. (2014). No evidence of dehydration with moderate daily coffee intake: A counterbalanced cross-over study in a free-living population. PLoS ONE, 9(1), e84154. https://doi.org/10.1371/journal.pone.0084154
5. Zhang, Z., Hu, G., Caballero, B., Appel, L., & Chen, L. (2023). Coffee consumption and hydration status in healthy adults: Evidence from controlled trials. European Journal of Nutrition, 62(4), 1765–1773.
6. Institute of Food Science, Europe. (2019). The impact of roast level on caffeine content and flavour profile in Arabica and Robusta coffee beans. Food Research International, 116, 59–66.
7. European Food Safety Authority (EFSA). (2015). Scientific opinion on the safety of caffeine. EFSA Journal, 13(5), 4102. https://doi.org/10.2903/j.efsa.2015.4102
8. National Health Service (UK). (2023). Caffeine and health: Facts and recommendations. NHS.uk. https://www.nhs.uk/live-well/eat-well/food-types/food-facts/caffeine