Drinking coffee: advantages and disadvantages of its consumption

Neuroscience reveals some little-known aspects of the habit of consuming coffee.

The history of coffee dates back to the 14th century in Ethiopia.awhere it began to be attributed stimulant properties. From the Horn of Africa its use spread to Yemen in the XV century and from there it extended to the rest of the Middle East and North Africa. It was the trade of Venetian ships with the Middle East that brought coffee to Europe, from where it was introduced to America (Cano-Marquina, Tarín and Cano, 2013).

In Spain alone, 14 billion cups of coffee are consumed per year, with the average weekday coffee consumption being 3.6 cups per day among those over 15 years of age. It should be added that 22 million people in Spain drink at least one coffee daily (Ramírez, 2016). These consumption patterns are similar in America and the rest of Europe, with the Nordic countries leading in terms of per capita consumption.

Therefore, taking into account how established caffeinated beverages such as coffee are in the Western diet, the study of their short, medium and long term effects has become an important issue, the study of its effects in the short, medium and long term has become of great importance.. Analyses and research have been carried out at both the psychological and physiological levels.

What is coffee composed of?

One of the main components of coffee, and which acquires its name from it, is caffeine. This substance, which we ingest in each cup, is a vegetable alkaloid that acts as an antagonist of the adenosine receptors in the nervous system.. 

Caffeine prevents the degradation of cyclic adenosine monophosphate by phosphodiesterases, which enhances post-synaptic neurotransmission in the sympathetic nervous system. Because of this, one of the main effects of caffeine on the organism is, by increasing the intensity of transmission, to provoke an activation in the organism (Glade, 2010). Although caffeine is the best known, within a cup of coffee we can find, among others, components such as vitamin B3, magnesium and potassium, among others..

Beneficial effects of its consumption

According to the information provided by science over dozens of years of research, it seems that the positive effects of moderate and chronic coffee consumption far outweigh the possible harm that it can cause. In the consequences and effects of caffeine consumption are involved other factors that increase the state of alertness, besides the substance itself, such as, for example, the personality of the consumer and the time of day (moment of the circadian cycle).

Caffeine improves, above all, the performance in vigilance tasks and in other simple tasks that require sustained attention. It also increases the level of alertness and reduces the sensation of fatigue (both mental and physical), and this effect may be beneficial for sports practice. These effects are especially marked when, due to the situation, the subject's level of activation is markedly low (night work, driving on a highway with few curves, etc.). Taking the latter into account, the use of caffeine can lead to an increase in safety and efficiency in certain jobs and in environments such as driving (Smith, 2002). Moderate consumption has also been linked to a decrease in the incidence of Diabetes and liver disease (Cano-Marquina, Tarín, & Cano, 2013).

Returning to its relationship with adenosine, in recent years, studies have been carried out to evaluate the neuroprotective role of caffeine in certain diseases.. Adenosine itself plays an important role in the control of brain disorders, having inhibitory A1R receptors (which would function as an obstacle to neurodegeneration) and facilitatory A2AR receptors (whose blockade would alleviate the long-term damage of various neurodegenerative conditions). Caffeine would come into play by acting as an antagonist of the A2AR receptor, which would favor the phenomenon of synaptic plasticity and, like the other antagonists of this receptor, would act as a cognitive "normalizer", preventing deterioration and reducing its progression.

Therefore, this could be a promising start in the study of adenosine A2AR receptor blockers, bringing new and diverse therapeutic options for the treatment of early stages of, for example, Alzheimer's disease (Gomes et al., 2011).

The bitter side of caffeine

Regarding the harmful effects of caffeine, Smith (2002), in his review of the subject, states that these harmful effects only appear under certain conditions. One of them would be when consumed by people with anxiety problems, whose level of activation is already high.

In people not affected by this problem, the negative effects would occur when excessively high amounts are consumed. The ingestion of beverages such as coffee, in these situations, would provoke an increase in anxiety. and this would result, for example, in tachycardia, sleep difficulties, or even impaired fine motor control (Smith, 2002). When consumption exceeds approximately 300 mg per day, the motor system may be greatly activated, the sleep-wake cycle may be altered, and brain metabolic rates may be increased across the board.

Although, as with many other substances, inappropriate caffeine consumption can lead to various problems, there are reasons to be optimistic in this regard. Almost all consumers have a low to moderate intake (50-300 mg per day), and it is at these doses that the beneficial behavioral effects mentioned above appear. In spite of the fact that there are people who qualify coffee and, therefore, caffeine, as a socially accepted drug, the cerebral mechanisms that are affected when consuming this psychostimulant differ greatly with respect to other substances of abuse such as cocaine, amphetamines, alcohol, THC and nicotine (Nehlig, 1999).

Why then does this consumption not reach harmful levels?

The area of the brain most related to drug dependence is considered in neuroscience as the pleasure area, i.e., the nucleus accumbens. This nucleus is divided both functionally and morphologically into a central area and the area of the cortex. The mesolimbic dopamine system, which originates in the ventral tegmental area and ends in the nucleus accumbens, also plays an important role in the reinforcement of addictive behavior.

Sufficient quantities to feel the effects of drugs of abuse such as cocaine, alcohol and so on, selectively activate dopaminergic neurotransmission in the cortex of the nucleus accumbens, which sustains the very high addictive capacity of these substances.which sustains the very high addictive capacity of these substances. In contrast, the caffeine consumption necessary to activate their properties increases dopamine release only in the caudate nucleus without inducing any release in the nucleus accumbens. This selective activation of the caudate nucleus would be related to the stimulatory properties of caffeine on psychomotor activity.

On the other hand, caffeine also stimulates dopamine release in the prefrontal cortex, which would be consistent with its psychostimulant properties and with the reinforcement of drinking behavior. For caffeine to increase the functional activity of the nucleus accumbens cortex, it would have to be consumed in an amount five times the daily average. This high consumption would activate many other brain structures such as most of the limbic and thalamic regions and those related to the extrapyramidal motor system. This would explain the side effects of excessive consumption. As a conclusion to these data, Astrid Nehlig (1999) states that in spite of the fact that caffeine meets some criteria to be considered a drug of abuse, there is a very low risk of addiction..

Finally, taking into account the good capacity for self-regulation by the general population, both in terms of the amount to be consumed and the time of day, knowledge of the pros and cons of something as common as drinking a cup of coffee, will favor an even more responsible consumption. In light of the information provided by scientific research, there seems to be no more powerful excuse to take a break and have a coffee with friends, family or co-workers than to improve one's own health. All for the sake of well-being.

Bibliographic references:

• Cano-Marquina, A., Tarín, J. J., & Cano, A. (2013). The impact of coffee on health. Maturitas, 75(1), 7-21.
• Glade, M. J. (2010). Caffeine - not just a stimulant. Nutrition, 26(10), 932-938.
• Gomes, C. V., Kaster, M. P., Tomé, A. R., Agostinho, P. M., & Cunha, R. A. (2011). Adenosine receptors and brain diseases: neuroprotection and neurodegeneration. Biochimica et Biophysica Acta (BBA)-Biomembranes, 1808(5), 1380-1399.
• Nehlig, A. (1999). Are we dependent upon coffee and caffeine? A review on human and animal data. Neuroscience & Biobehavioral Reviews, 23(4), 563-576.
• Ramirez, E. (2016). The presence of coffee in the lives of Spaniards is increasing - elEconomista.es. Eleconomista.es. Retrieved from: http://www.eleconomista.es/empresas-finanzas/consumo/noticias/7174035/11/15/Crece-la-presencia-de-cafe-en-la-vida-de-los-espanoles.html
• Smith, A. (2002). Effects of caffeine on human behavior. Food and chemical toxicology, 40(9), 1243-1255.