Caffeine, the most commonly consumed psychoactive drug to date, has been subject to praise and scrutiny since 3000 BCE; its history, usage, and health effects are well worth discussion.
It’s difficult to imagine a person in today’s society that hasn’t heard of caffeine, whether as a daily essential or absolute abstinence; caffeine has likely found its way into your life – otherwise, why would you be reading this?
Caffeine can help bring focus and clarity to some while also bringing anxiety, ulcerations, and high blood pressure. Regardless of how it affects us, it depends on the individual, Its source and dosage.
What is Caffeine?
Caffeine is a bitter organic compound of the methylxanthine class that acts as a central nervous system (CNS) stimulant, also known as a cognitive enhancer. Structurally, caffeine is an alkaloid and purine very closely related to adenine & guanine – one of four nucleotides that form DNA and RNA. Caffeine can go by a few names, such as guaranine in guarana, theine in tea, and mateine in mate.
Biologically caffeine is thought to act as a deterrent to herbivores due to its bitter taste but to entice other species (such as Honey Bees)
Caffeine was first identified after it was isolated from coffee by German chemist Friedlieb Ferdinand Runge 200 years ago in 1819. However, the discovery of caffeine-containing sources was much further back in 3000 BCE when Emperor Shennong of China discovered tea. After, he noticed certain leaves added to boiling water had a specific aroma and restorative nature (the aroma is because of Tannins, but we’ll discuss that later).
Because of this effect, many regulations and restrictions have been imposed on caffeine throughout history. From the Ottomans making it illegal for some lower classes to Sweden, which banned coffee for nearly a century!
Caffeine can help bring focus and clarity to some while also bringing anxiety, ulcerations, and high blood pressure. Regardless of how it affects us, it depends on the individual, its source and dosage. Get in touch with me to find out how it affects you, personally.
How Does Caffeine Work In Our Body?
One of the reasons we feel tired towards the end of the day is due to the build-up of a compound called Adenosine. Adenosine binds to receptors in our synapses which causes our cells to signal that tired feeling. After a sound, restful night’s sleep (the kind where you wake up with sleep marks and a little drool), adenosine has been filtered out, allowing us to start the day fresh and alert.
Caffeine is very similar to adenosine, which means it competes with the same receptors as adenosine – think of a game of musical chairs; the more caffeine playing, the less adenosine can take a chair, leaving them floating around while caffeine enjoys the luxury of sitting. As a result, it stops adenosine from accumulating, making us feel awake.
Caffeine will also cause more Acetylcholine to be released, which will further the effects of caffeine’s mental alertness. Depending on age, genetics, and liver function, caffeine generally lasts in the body for 3-7 hours.
Other Caffeine Effects On Our Bodies
Given what is said above, it is obvious caffeine can wake us up – which I’m sure most of us have experienced first-hand – but what else does it do?
Arguably the best use for caffeine is its medical uses – especially for premature infants. It is often prescribed to premature infants with apnea (inability to breathe) to prevent and treat bronchopulmonary dysplasia (underdeveloped, immature lung function), reduce cognitive and language delays in infants and even promote healthy weight gain.
It has also been used therapeutically in adults to treat orthostatic hypotension (drop in blood pressure from postural changes), as a second-line treatment for ADHD, and even to reduce the length of hospital stay after bowel surgeries.
Caffeine is often prescribed with paracetamol as it enhances paracetamol’s pain-relieving effects. The caffeine/paracetamol/aspirin combination is a preferred first-line treatment for mild pain relief and temperature regulation.
Caffeine has also been shown to reduce or minimise the effects of depression. It has also been said to have protective effects against Alzheimer’s and dementia, although more research is needed.
Caffeine is mainly used as a performance enhancer and ergogenic aid. It has improved performance for anaerobic exercises (sprinting, running) and strength exercises. It delays muscle fatigue, initiates lipolysis (fatty acid breakdown), and increases basal metabolic rate.
Despite this medicinal use of caffeine, it is not without its flaws. Its adverse effects are also crucial to consider. For example, caffeine is known to worsen reflux by increasing gastric acid secretion, which can worsen gastritis and cause peptic ulcer disease.
Another risk with caffeine is its diuretic effect. It causes an increase in urination which causes fluid loss and can lead to dehydration. However, this effect is minimised with chronic consumption due to developed tolerance.
Caffeine is notorious for its psychological side effects. Because of its stimulant nature, caffeine can cause mild anxiety and jitteriness, insomnia and sleep disruption, worsening anxiety disorders, and even causing caffeine-induced anxiety disorder.
Although caffeine is thought to be addictive, there isn’t much literature that supports this. Still, withdrawal and dependence on caffeine are acknowledged.
Caffeine will also cause more Acetylcholine to be released, which will further the effects of caffeine’s mental alertness. Depending on age, genetics, and liver function, caffeine generally lasts in the body for 3-7 hours. So if you’d like to learn more about optimising your diet so you don’t feel tired at the end of the day — with or without caffeine — let’s talk.
Caffeine Dosage and Sources
How much caffeine is too much? Paracelsus, the father of toxicology, said, “All things are poison, and nothing is without poison, but the dose makes it clear that a thing is not a poison.” So too much of anything is bad; everything is in moderation!
The FDA believes that caffeine is ‘generally regarded as safe’, and EFSA has stated that up to 400 mg of caffeine (5.7 mg/kg of body weight) shows no adverse effects and does not raise any safety concerns. However, for pregnant women, the recommended limit for pregnant women is 200 mg of caffeine per day. One study, it was shown that only doses above 600 mg of caffeine resulted in increased blood pressure and an increased risk of cardiac distress. Furthermore, toxic doses of caffeine can go up to 10 g or a lethal amount of up to 200 mg/kg body weight. So how much caffeine can we consume in a day?
Sources Of Caffeine
Over 60 plants contain caffeine in their leaves, flowers, and seeds. The most common sources of caffeine come from coffee beans and tea leaves, while often added to soft drinks and energy drinks.
Coffee
Coffee is the most well-known caffeine-containing beverage – with about 90% of the global population consuming coffee. The question of modern-day society is how much caffeine is in your coffee? Answering that question is tricky because caffeine content varies drastically depending on the bean used (Robusta can have more than double the caffeine as Arabica) and the preparation methods used. Even espresso caffeine content can vary by the powder’s grams, the water’s temperature, and the time spent pressing water through the beans. Generally, french-press coffee will have higher caffeine content than espressos and cappuccinos. Notably, water, milk and sugar added to coffee do not affect the caffeine content.
Furthermore, instant coffee is said to be lower in caffeine than espresso, which is valid to some extent; however, this still depends on how many grams of instant coffee is used. For example, 1.8 grams (1 level teaspoon) of instant coffee will have less caffeine (57 mg) than a cappuccino (63 mg), but 2.5 g of instant coffee can give you 85 mg per cup. As a good rule of thumb, you can assume one cup of coffee (1 tsp of instant and 15 grams of ground coffee) will give you 60-100 mg; therefore, recommendations suggest that coffee intake be limited to 4 cups daily.
Tea
Tea leaves are also a source of caffeine. Although tea contains half the caffeine content of coffee, generally. However, just like coffee, tea’s caffeine content varies based on the types of leaves used, the preparation method, and the ageing of the tea. For example, black tea (roughly 40 mg per cup) is made by allowing the tea leaves a long period to oxidise and dry, increasing caffeine concentration. On the other hand, green tea (approximately 18 mg per cup) is given a brief period to oxidise and has a much lower caffeine content.
Soft Drinks, Energy Drinks, Decaf
Most soft drinks contain caffeine; the label indicates the amount. In comparison, your average energy drink (Monster, Redbull, Switch) contains about 150 – 300 mg per serving. The caffeine in these drinks usually comes from excess caffeine as a result of producing decaffeinated coffee.
Decaf coffee still contains caffeine, much less than regular coffee, as it is impossible to remove all caffeine.
Caffeine has many health benefits, from improving blood pressure to preventing depression, but just like everything else in life, overconsumption may lead to adverse effects. Caffeine is in varying quantities in cacao beans, coffee beans, and tea leaves. Four cups of regular coffee are likely to provide more than 400 mg of caffeine, increasing the risk of adverse effects. It’s an age-old stimulant with a deep-routed history in human cultures and is the most commonly consumed psychoactive by far!
Caffeine affects us all differently, and to determine if it harms your health, see your health professional! You can book a session with your favourite dietitian (me) here. If you want to know more about caffeine and its products, click the link to see more resources or contact me with your question!
