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Most of us are unable to start out the day without a shot of coffee.  According to the International Coffee Organization, almost 2 billion cups of coffee are consumed globally every day.


The US Food and Drug Administration (FDA) states that the average amount of caffeine which is consumed daily in the US is approximately 300mg per person - the equivalent to between two and four cups of coffee. This is considered to be a moderate daily caffeine intake, which according to many studies, can promote a variety of health benefits.

However, some studies claim otherwise, going as far as suggesting that one or two cups of coffee a day may have a negative impact on our health.


So, what are we to believe?


Let’s examine the potential health benefits, as well as the negative side effects of consuming caffeine.


Caffeine is a natural stimulant - The main ingredient in coffee is caffeine - a compound that is derived naturally from over 60 different plant sources, including coffee beans, tea leaves, cacao seeds and cola nut seeds.  Caffeine is known to act as a stimulant by activating the central nervous system. It can combat fatigue and improve concentration and focus.


According to the University of Michigan Health Service, caffeine’s stimulating effects can start as soon as 15 minutes after consumption and may last up to 6 hours.


Other than coffee, caffeine is often consumed through tea, soft drinks - particularly energy drinks - and chocolate. It is also found in some prescription and non-prescription medications, such as cold, allergy and pain medication.

Caffeine's potential health benefits – aside from its effects as a stimulant, caffeine has been regarded as providing an array of health benefits.

Recently, Medical News Today reported on a study suggesting that consuming three cups of coffee a day may reduce the risk of liver cancer by 50%, while another study suggests that drinking four cups a day could halve the risk of mouth and throat cancer.


Caffeine consumption has also been associated with positive effects on our brain.  Lately, a study from the Harvard School of Public Health suggested that drinking between two and four cups of coffee a day may reduce suicide risk in adults, whilst a more recent research found that ingesting 200 mg of caffeine each day may boost long-term memory.  Other studies have also suggested that caffeine intake may protect against type 2 diabetesParkinson's disease, cardiovascular disease and stroke.


Caffeine: the socially acceptable ‘psychoactive drug' – There is a lot of research that suggests that caffeine consumption can benefit our health, and considering the number of products that contain the stimulant, there is little wonder caffeine consumption is so common.  Nonetheless, we mustn’t forget that caffeine is a psychoactive substance - a drug that crosses the blood-brain barrier to stimulate the central nervous system.  This is notwithstanding the fact that unlike most other psychoactive substances, caffeine use is socially acceptable, and the drug is widely used. In fact, caffeine is the most commonly used psychoactive substance globally.


Furthermore, the great majority of caffeine consumers use the substance regularly without apparent harm. These factors are likely contribute to the perspective that caffeine is a benign substance that everyone can use without suffering from any negative consequences.


The negative effects of caffeine consumption – Yet, there can be negative consequences from caffeine consumption, particularly if consumed in high quantities.  The Mayo Clinic state that consuming more than 500-600 mg of caffeine a day may lead to insomnia, nervousness, restlessness, irritability, an upset stomach, a fast heartbeat and even muscle tremors.  However, earlier research has linked even moderate amounts of caffeine to negative health effects.


In 2014, Medical News Today reported on a study suggesting that consuming 300 mg of caffeine a day during pregnancy may increase the risk of low birth weight babies, while other research suggests that drinking four cups of coffee a day may increase the risk of early death.


Effects of caffeine vary from person to person – This may explain why there are mixed messages surrounding whether caffeine is good or bad for us.  For example, individuals with anxiety disorders are more susceptible to the anxiogenic effects of the caffeine.  Caffeine can also metabolise at different rates amongst individuals for various reasons. For example, cigarette smokers metabolize caffeine twice as fast as non-smokers.  However, caffeine metabolism is slower among infants, pregnant women and individuals with liver disease. In addition, some medications slow caffeine metabolism, which may increase the risk for caffeine intoxication. But the effects of caffeine also vary simply because we're all different.


It is very likely that the effects of caffeine are dependent on each person's genetic characteristics and lifestyle factors.  Thus, some people may have difficulty sleeping or experience tremors or stress with relatively low caffeine intakes and it is useful to be aware of these symptoms and reduce caffeine intake if these occur.


Caffeine addiction and withdrawal – Taking into account the positive effects caffeine can have as a stimulant, for some people this can result in caffeine addiction.  Caffeine activates many of the same behavioural and neuropharmacological mechanisms that are activated by other ‘reinforcers’, including other abusive drugs.


And, like many other reinforcers, caffeine is associated with various positive subjective effects like increased wellbeing, sociability, and feelings of energy and alertness. Partly this is why a small percentage of the population develops caffeine use disorder.  Furthermore, some people can become physically dependent on caffeine, with absence or reduction of coffee consumption in these individuals resulting in caffeine withdrawal.  This can trigger symptoms such as headache, fatigue, drowsiness, depression, irritability, concentration difficulties, nausea and vomiting.  Dependence can become so strong for some individuals that they're unable to reduce consumption despite knowledge of recurrent physical or psychological problems associated with continued use.


Kids and adolescents 'should avoid caffeine consumption' - Based on the negative side effects caffeine consumption can cause, doctors should be discussing caffeine use with their patients to determine whether they are consuming safe levels of the stimulant.  Especially when it comes to children and adolescents.  The majority of paediatricians recommend that children and teens should avoid caffeine consumption, particularly since it is unknown as to how excessive caffeine intake may impact brain development.  Notably, caffeine interferes with sleep, and sleep plays a critical role in learning. Some research suggests that caffeine interferes with sleep and learning among teens, which, which in turn, obstructs normal neurological development that is noticeable into adulthood.  Some psychologists are also concerned that a pattern of caffeine use or abuse among young people may lead to subsequent problematic drug and alcohol use.


The FDA clearly hold a similar view to paediatricians. In May 2014, the FDA announced it would be investigating the safety of caffeine in food products, particularly products aimed at children and teens.  The FDA are concerned that many food and drink products, such as jelly beans, waffles, syrup and chewing gum, now have caffeine added to them to enhance their stimulating effect. 


Michael R. Taylor, deputy commissioner for foods and veterinary medicine at the FDA, said:


"We're particularly concerned about children and adolescents and the responsibility FDA and the food industry have to protect public health and respect social norms that suggest we shouldn't be marketing stimulants, such as caffeine, to our children."


Studies have shown high caffeine intake may also produce negative side effects in pregnant women and individuals with heart conditions or anxiety disorders.  However, the majority of us consume caffeine in moderation without any harmful side effects, so healthy adults should not be overly concerned.  Yet we should be mindful that when we consume caffeine, we are consuming a psychoactive substance that can cause or exacerbate some pre-existing health problems.


20 Harmful Effects of Caffeine

18 Good Health Reasons To Drink Coffee




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