Caffeine's Neurologic and Metabolic Effects

This study aims to identify the metabolic pathways that caffeine in the body upregulates and their impact on physical activity. Caffeine's effects on the metabolism and bodily activities can be mapped using thorough study and successfully performed studies. Caffeine metabolism is influenced by the user's genotype and physical condition. Pregnancy, illness, genotype, and personal choice all affect caffeine usage and effects differently. Caffeine's natural effect on the body's mental and physical activity is directly influenced by the mechanism by which it is metabolized. Use of caffeine has been related to both negative effects in specific circumstances and enhanced immunity to some diseases. Research further indicates that withdrawal from caffeine use can lead to undesired results like insomnia and anxiety. The different metabolism pathways of caffeine lead to varying physical effects in different individuals as detailed in this research paper



Introduction

Caffeine is arguably the most widely consumed drug in the world. The widespread use of caffeine is due to its presence in coffee, tea, chocolate and other beverages. For its obviously psychoactive effects, caffeine has been labeled a harmful drug by many. Nevertheless, research into the modus operandi of caffeine in the Central Nervous System (CNS) indicates that this conclusion about caffeine is mostly unjustified. When used in moderation, caffeine can improve mental and physical ability of the user. Caffeine binds to the adenosine receptors in the brain to induce activity rather than inactivity propelled by adenosine. However, as with any other drug, prolonged caffeine use causes addiction and can have adverse effects on the user’s overall health. Addiction is the yardstick used by critics to beat caffeine with despite the lack of conclusive evidence on the subject. One thing is for sure. However, caffeine is a psychoactive drug that, in the least, affects the neurology and metabolism of the user.

Chemical Composition of Caffeine

Caffeine is a natural stimulant of the methylxanthine class, and its biological nomenclature is 1, 3, 7-trimethylxanthine. Caffeine can be found inherently in tea, coffee, and even cocoa. Humans mostly ingest caffeine orally as drink or food. The chemical structure of caffeine allows it to embed into the central nervous system where it can influence metabolism, heart rate, and dieresis. Caffeine is an alkaloid that can have both positive and negative effects on the body depending on its consumption.





Metabolism of Caffeine

Metabolism of caffeine in the body is at an astonishing 96-97%; meaning only about 3% of the caffeine consumed fails to be metabolized. In humans, about 80% of caffeine follows the metabolic pathway from N, 3-demethylation to 1, 3 dimethylxanthine by CYP1A2 in the liver. Of the remaining 20%, 17% of ingested caffeine follows the pathway from demethylation to either theobromine or theophylline. Such is the high rate of metabolism of caffeine that only the remaining 3% finds its way into the urine. Secondary metabolism of primary metabolites leads to urinary metabolites of methyluric acid, methylxanthines, and dimethyluric acid. CYP1A2 is the chief primary metabolism agent of caffeine in the body.

Unlike conventional drugs, caffeine is known to trigger the prefrontal cortex to release dopamine rather than in the typical nucleus accumbens that controls dopaminergic activity. This property of caffeine of switching the timing and location of dopamine release is in line with its reinforcement abilities. Reinforcement is the ability of a drug to influence the future likelihood of usage by the user. For this reason, caffeine has been reported to be liked by virtually all its users. However, reinforcement of caffeine is only useful when the drug is consumed moderately, or in low quantities.1 Caffeine has a half-life of about 4-6 hours in the human body. Nonetheless, it requires only less than two hours for caffeine to be integrated into the bloodstream.









Effect of Caffeine on Physical Performance

Caffeine is proven to be a catalyst for increased physical activity and endurance. Anaerobic metabolism induced by caffeine enables the muscles to relax and build up a tolerance. The chemical structure of caffeine allows it to bind to adenosine receptors in the brain and induce a reverse effect. Adenosine receptors are released in the brain to control the sleep-wake cycle in humans. Adenosine released in the central nervous system serves to increase drowsiness and inactivity in the body. Caffeine fundamentally disrupts this process by upregulating the release of adenosine in the brain.2 Instead of causing the muscles and heart rate to go to sleep, caffeine engineers the opposite effect.

Caffeine increases vasodilatation when used in low to moderate amounts. Theobromine released during metabolization of caffeine is responsible for causing this dilation of blood vessels.1 This feature also coincides with increased urine production in the body. Also, caffeine stimulates the body to feel more energized, active and mobile. It is this effect that endears so many users of caffeine to the drug. Theophylline production by CYP1A2 metabolism of caffeine leads to relaxation of the gastroesophageal muscles. Study of variants like CYP1A2 allele shows increased levels of metabolism in specific groups of people; heavy smokers, for instance, have a high metabolism rate for caffeine. This is due to the direct effect of smoking on CYP1A2 that reduces the half-life of caffeine in smokers. Other groups like a pregnant woman, newborn babies, and people with liver complications possess a considerably low caffeine metabolism rate regardless of their genotype.





Effect of Caffeine on Mental Performance

Caffeine has been discovered to induce increased cognitive abilities in the users. Additionally, the use of caffeine in women is linked to a slower rate of loss of cognitive abilities with age. The users of caffeine cite increased mental activity and capacity as compared to non-users of caffeine. Caffeine is undetectable in the brain as it embeds into adenosines and sends stimulating instructions to the rest of the body rather than the lulling effect usually induced by adenosines. However, the brain learns to develop resistance to caffeine over time with increased use. The resistance to caffeine varies in humans and also in other animals as indicated by research.2 Animals easily builds resistance as compared to humans who are likely to uphold caffeine consumption for a more extended period.

Withdrawal from constant caffeine use leads to upregulation of adenosine in the central nervous system. Upon reduced consumption or withdrawal from caffeine, the mind releases more adenosine in anticipation of the usual increased level of caffeine use. Smokers indicate a higher addiction rate and a higher consumption rate of caffeine as compared to non-smokers. Nevertheless, it is difficult for biologists to ascertain the exact effect of caffeine use due to the use of many other drugs by caffeine users; caffeine is mostly treated as a mild drug.

Health Effects of Caffeine

Caffeine is attributed to some adverse health effects in the body. Insomnia, anxiety, pregnancy complications, hypertension and bladder problems are some of the issues linked to caffeine use. Pregnant mothers are warned against dependence on caffeine as it could cause spontaneous miscarriages or lack of fetal growth. A small section of the human population has also reported allergic reactions to caffeine saying it brings them negative effects.

However, caffeine use has been proven to have some beneficial effects on humans. Caffeine has been attributed to lower the risk of Parkinson’s disease in its users of CYP1A2 rs762551 genotype CC and rs2470890 genotype CC. Furthermore, research indicates that the C allele of CYP1A2 rs762551 caffeine users has an inherently lower risk of contracting breast cancer than same type non-consumers of caffeine. Research further indicates that caffeine use leads to lower risk of cardiovascular diseases as compared o non-users.



























Conclusion

Caffeine is a highly-consumed drug and will remain so for a while. Nevertheless, it has splitting effects upon its various users. For some users, caffeine offers stimulation, mental and physical stimulation and protection from diseases like cancer and Parkinson’s disease. For others, however, caffeine brings negative effects namely insomnia, anxiety and pregnancy failures. The effect of caffeine on the user depends on the metabolic pathway inherent to the user’s neural composition and situation. Smokers exhibit a higher metabolism of caffeine as opposed to a lower rate in non-smokers. Pregnant women, neonates, and people with liver problems have a significantly lower rate of caffeine metabolism. Generally, caffeine metabolism varies from person to person and determines its effect on the user’s physical activity.



















Reference

Dar´ıo Echeverri, F´elix R.Montes,Mariana Cabrera, Ang´elica Gal´an, Ang´elica Prieto. "Caffeine’s VascularMechanisms of Action." International Journal of Vascular Medicine (2010): 163-185. Print.

Gerald C. Claghorn, Zoe Thompson, Kristianna Wi, Lindsay. "Caffeine stimulates voluntary wheel running in mice without." Physiology & Behavior (2016): 1-32. Document.