Caffeine consumption

Coffee has been one of the most consumed beverages in the world for centuries. Historically, it has been surrounded by popular beliefs, although, at present, there are multiple scientific studies that attribute beneficial and also negative effects to it.

Caffeine is the most widely consumed psychostimulant substance in the world and can be found in coffee, tea and other food products.

Caffeine was discovered for the first time in 1819 and, since then, its consumption has been increasing worldwide. It is mainly consumed in infusions extracted from the fruit of the coffee plant and tea leaves, although it is also present in yerba mate and guarana fruit.

In humans, it acts as a central nervous system stimulant, restoring alertness and eliminating drowsiness, although studies to date attribute other effects to it:

  • Antioxidant effect: caffeinated beverages also contain antioxidant compounds such as flavonoids to which protective effects against various diseases are attributed.
  • Diuretic effect.
  • Neuroprotective in neurodegenerative diseases. Some studies show the protective character of moderate caffeine consumption in diseases such as Parkinson's or Alzheimer's disease.
  • Helps in migraine attacks and headaches due to its vasoconstrictor action and enhances the effect of some analgesic drugs.
  • It improves sports performance, with a peak of action between 2-4 hours after its consumption.

All the beneficial effects of caffeine are associated with moderate consumption, however, its abuse (more than 400mg per day) can produce harmful effects that include restlessness and tremors, insomnia, headache, tachycardia, anxiety and dependence.

Although the effects of caffeine are short-lived because it does not accumulate in the body, each person may react differently. For example, pregnant women can take up to three times longer to metabolize the compound, while smokers eliminate it much faster.

The factors involved in the greater or lesser consumption of caffeine from sources such as coffee, tea or others have been the subject of study in recent years, having been related to some medical pathologies such as diabetes or cardiovascular diseases.One of the largest GWAS studies carried out on coffee consumption, with more than 400,000 participants, has identified 31 associated markers, some of which belong to genes that regulate caffeine metabolism, such as the AHR gene and the CYP1A2 gene, or the ADORA2A gene, related to the development of anxiety from caffeine consumption.

Number of observed variants

13.5 million variants

Number of loci analyzed in the study

28 loci


Said MA, van de Vegte YJ, et al. Associations of Observational and Genetically Determined Caffeine Intake With Coronary Artery Disease and Diabetes Mellitus. Journal of the American Heart Association, 08 Dec 2020, 9(24):e016808

Kolahdouzan M, Hamadeh MJ. The neuroprotective effects of caffeine in neurodegenerative diseases. CNS Neurosci Ther. 2017 Apr;23(4):272-290.

Barcelos RP, Lima FD, Carvalho NR, Bresciani G, Royes LF. Caffeine effects on systemic metabolism, oxidative-inflammatory pathways, and exercise performance. Nutr Res. 2020 Aug;80:1-17.

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