Caffeine is an alkaloid which occurs naturally in about sixty different plant species.  The most common of these include cocoa beans, kola nuts, some tea leaves and coffee beans.  Also, coffee, certain sodas, energy drinks, soft drinks and tea contain caffeine which may be obtained from the raw materials used in their preparation or otherwise. 
Caffeine is reported to be the most commonly consumed psychoactive drug in the world. Its consumption has become very popular among children and adolescents, with statistics showing a 70% increase in the last 30 years.[2, 3] From the 1980s to the year 2005, the average amount of caffeine consumed by children and teenagers (ages 5 to 18) has increased from 38 mg per day to 69.5 mg per day. The December 2010 issue of the Journal of Pediatrics shows an increase to about 109 mg of caffeine consumed in a day for children in a similar age range. These constantly increasing values show the need for individuals to check the amount of caffeine taken daily and how this could affect their health positively or negatively.
Several studies have been carried out to determine the optimum amount of caffeine required by a healthy individual. It is recommended that the daily intake of caffeine for developing teens should not exceed 100 mg ( this is equivalent to 3 cans of coke, 1.25 cans of red bull energy drink, 0.6 of a 16 fl. oz. can of Monster Energy Drink, and 0.2 of a Starbucks Venti brewed coffee). For most healthy adults, the recommended daily allowance is 400 mg. It is advised that a maximum of 2.5 mg of caffeine per kg of body weight should be consumed by children. It must be noted that variations in population, as well as changes in the health condition of individuals over time, play a major role in the amount of caffeine required by an individual irrespective of his or her age group.
The intake of caffeine through major sources such as cola beverages (55%), tea (30%), and chocolate (14%) may have positive and negative implications on the consumer depending on the health status of the consumer as well as the amount of caffeine being consumed. 
Research by the US Food and Drugs Administration, amongst others, has shown that moderate caffeine intake can play an important role in enhancing a variety of health benefits. 
Firstly, consuming 3-4 cups of coffee a day may reduce the risk of developing some cancers such as cancer of the liver, mouth and throat in the average individual.  Secondly, some studies suggest that adults who consume between 2-4 cups of coffee daily are less likely to commit suicide.  The biochemistry of this finding is suspected to involve the inhibition of the brain chemical adenosine (a depressant) and stimulation of dopamine (a stimulant), which makes one feel good. 
Another benefit of caffeine intake is that it improves metabolism (about 3-11%) and the rate of fat breakdown (about 10% and 29% in obese and slim persons respectively).  Some observational studies indicate that individuals who regularly take in an ideal amount of caffeine may also reduce their risk of developing brain disorders such as Alzheimer’s disease. 
Although caffeine can have the above-mentioned health benefits, it can also have adverse effects on the body, especially when taken in excess. These negative effects can be categorized under psychological effects including disorders, dependence and withdrawal, and certain adverse effects.
The psychological effects of caffeine overdose include disorders such as anxiety disorders, sleep disorders and eating disorders.  Excessive intake of caffeine and anxiety are known to share similar symptoms, and both conditions are suspected to be the underlying factors for increased activity of the sympathetic nervous system.  Some studies suggest that caffeine overdose may trigger and reinforce the symptoms of anxiety by increasing the level of lactate in the brain. [12, 13]
The quantity and quality of sleep can be altered by caffeine overdose.  Insomnia is the most common symptom observed in most individuals. This effect may be very disadvantageous for older people and children. Sleeplessness may cause headaches, lack of concentration and irregular daytime sleeping among children. 
Caffeine overdose can worsen the condition of individuals suffering from eating disorders such as bulimia nervosa and anorexia nervosa. Patients with anorexia and bulimia sometimes consume excess caffeine with the hope of boosting metabolism and suppressing appetite. However, the stimulant effect of caffeine can increase the risk of cardiac arrhythmias and osteoporosis, especially among anorexia patients 
Caffeine, like other psychoactive substances, results in certain desirable stimulant effects and undesirable withdrawal symptoms. The difference is that the effects of caffeine are less dangerous as compared to those of other psychoactive substances such as cocaine.  The common withdrawal symptoms associated with caffeine overdose include insomnia, nausea, confusion and anxiety.  These symptoms normally disappear after ingestion of caffeine.
Large doses of caffeine intake have adverse diuretic and gastrointestinal effects. In the gastrointestinal tract, it causes the esophageal sphincter to relax and thus leads to gastro-esophageal reflux disease. [19, 20]
Lastly, caffeine overdose increases the risk of developing sinus tachycardia, migraine, and miscarriage or low birth weight in pregnancy. [21 – 23] Pregnant women are advised to consume less than 300 mg per day of caffeine. 
Conclusively, caffeine could be beneficial when taken in the right amount but excess intake can be very harmful to one’s health.
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- National Council on Strength & Fitness. Caffeine Consumption Among Children and Adolescents – Online Articles: National Council on Strength and Fitness Trainer’s Tools [Internet]. [cited 2016 Sep 6]. Available from: https://www.ncsf.org/enew/articles/articles-caffeineconsumptionchildrenadolescents.aspx
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- Caffeine Informer. Caffeine Safe Limits: Determine Your Safe Daily Dose [Internet]. [cited 2016 Sep 6]. Available from: http://www.caffeineinformer.com/caffeine-safe-limits
- Caffeine Consumption in Children and Teens [Internet]. myVMC. 2010 [cited 2016 Sep 6]. Available from: http://www.myvmc.com/lifestyles/caffeine-consumption-in-children-and-teens/
- Whiteman H. Caffeine: how does it affect our health? [Internet]. Medical News Today. [cited 2016 Sep 6]. Available from: http://www.medicalnewstoday.com/articles/271707.php
- Dwyer M. Coffee drinking tied to lower risk of suicide [Internet]. Harvard Gazette. [cited 2016 Sep 6]. Available from: http://news.harvard.edu/gazette/story/2013/07/drinking-coffee-may-reduce-risk-of-suicide-by-50/
- Gunnars K, | Bs. 13 Proven Health Benefits of Coffee [Internet]. Authority Nutrition. 2013 [cited 2016 Sep 6]. Available from: https://authoritynutrition.com/top-13-evidence-based-health-benefits-of-coffee/
- Maia, L., & De Mendonça, A. (2002). Does caffeine intake protect from Alzheimer’s disease? European Journal of Neurology, 9(4), 377–382. http://doi.org/10.1046/j.1468-1331.2002.00421.x
- Winston, A. P., Hardwick, E., & Jaberi, N. (2005). Neuropsychiatric effects of caffeine. Advances in Psychiatric Treatment, 11(6), 432–439. http://doi.org/10.1192/apt.11.6.432
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By: Millicenta Ampiah, final year Biochemistry student of Kwame Nkrumah University of Science and Technology (KNUST), Ghana.
©2016 Scientect e-mag | Volume 1 (1): A11