What is Caffeine?

Many of us consider caffeine as a delightful addition to our daily routine. It is sometimes celebrated, sometimes scorned. Both a saviour and an aggressor. Caffeine is the most commonly ingested psychoactive substance globally, yet it is mostly misunderstood. But what is caffeine?

Caffeine is a natural stimulant that belongs to a class of compounds called xanthines. It is found in various plants, most notably in coffee beans, tea leaves, cacao pods (used to make chocolate), and kola nuts (used in some soft drinks). Different cultures have ingested these plants worldwide for centuries, sometimes millennia, as they were prized by various cultures for their power to bestow "vitality" upon people. 

And good on you if you're intelligent enough to understand this, but its chemical structure is C8H10N4O2, and its systematic name is 1,3,7-trimethylxanthine. 

Where Does Caffeine Come From?

Plants produce caffeine as a natural defence mechanism to deter herbivores, with its bitter taste acting as a pesticide. However, studies have shown that caffeine can improve bees' memory, helping connect sweet nectar with the flowers of coffee plants and any others that have caffeine. This, in turn, ensures their return and aids the plants in their quest for pollination. All across the globe, certain plants evolved to have it independently. This phenomenon is known as convergent evolution. Below is a list of some of the most famous plants to contain caffeine.

  • Coffee Beans: Coffee is one of the most well-known sources of caffeine. And if you're on this site reading this, you probably already know that. The caffeine is found in the coffee plant's seeds, commonly called coffee beans.
  • Tea Leaves: Tea, whether black, green, white, or oolong, contains caffeine. The caffeine content in tea leaves can vary depending on the type of tea and how it's prepared.
  • Cacao Beans: Cacao beans, used to make chocolate and cocoa products, also contain caffeine. However, chocolate's caffeine content is relatively lower than coffee and tea.
  • Kola Nuts: Kola nuts, native to Africa, contain caffeine and are used in some traditional beverages and soft drinks. They are the source of caffeine for cola-flavoured sodas.
  • Guarana Seeds: Guarana is a plant native to the Amazon basin. Its seeds contain a significant amount of caffeine and are used in some energy drinks and dietary supplements.
  • Yerba Mate: Yerba mate is a South American beverage made from the leaves of the yerba mate plant. It contains caffeine and is popular in various countries in South America.

How Does Caffeine Affect the Body?

Most people get their caffeine kick by drinking it. Either in coffee, tea or soft drinks. Once consumed, caffeine is absorbed into the bloodstream from the stomach and intestines. It takes approximately 30-60 minutes for the effects to kick in. Caffeine does not actually wake you up but instead tricks your brain into believing you are not tired. 

Throughout the day, your brain creates a neurotransmitter called Adenosine. This neurotransmitter interacts with neurons in our brain, instructing us to eat, drink, or use the loo. Adenosine is what provokes drowsiness and promotes sleep. Our neurons identify various neurotransmitters because they have distinct shapes that attach in different ways, similar to a lock and key relationship. Interestingly, caffeine and Adenosine have almost identical chemical structures. Caffeine binds to the neurons and blocks Adenosine, causing the brain to stop producing it, resulting in increased alertness. 

It is this little trick that has ensured the enduring popularity of caffeine. 

What are the Potential Benefits of Consuming Caffeine?

The Health benefits of caffeine have proved hard to pin down. However, studies are increasingly showing that caffeine can benefit treating both Alzheimer's and Parkinson's disease. It has also shown potential as a preventative aid to both these conditions. Here are some of the potential benefits of caffeine consumption:

  • Increased Alertness and Focus: Caffeine is well-known for increasing alertness, improving concentration, and enhancing mental clarity. This can help individuals stay awake and attentive when they need to be alert, such as during work or studying.
  • Enhanced Cognitive Function: Caffeine has been proven to enhance memory, reaction time, and problem-solving skills, improving clarity of thought and more effective task performance.
  • Improved Physical Performance: Caffeine can boost physical performance by increasing the release of adrenaline, leading to improved endurance, strength, and athletic performance. Athletes and fitness enthusiasts often use it. In fact, it was a banned substance at the Olympics between 1984 and 2004.
  • Reduced Risk of Certain Diseases: Some research suggests that moderate caffeine consumption may be associated with a reduced risk of certain diseases. For example, studies have linked coffee consumption to a lower risk of Parkinson's disease, type 2 diabetes, and certain types of cancer.

It's important to note that the benefits of caffeine can vary from person to person. Every one of us metabolises caffeine differently. Individual tolerance to caffeine can also play a significant role in how it affects you, so it's essential to be mindful of your response to caffeine and adjust your consumption accordingly.

What are the Potential Negative Effects of Consuming Too Much Caffeine?

Unlike the health benefits of caffeine, the adverse effects of caffeine have been known for some time. Consuming too much caffeine can lead to various unfavourable effects, and individual tolerance to caffeine can vary widely. The negative consequences of excessive caffeine intake can include:

  • Insomnia and Sleep Disturbances: One of the most common side effects of excessive caffeine consumption is difficulty falling asleep or staying asleep. Caffeine can disrupt sleep patterns, leading to insomnia and poor sleep quality.
  • Nervousness and Anxiety: High doses of caffeine can lead to increased nervousness, restlessness, and heightened anxiety. Some individuals are more sensitive to these effects than others.
  • Increased Heart Rate and Blood Pressure: Excessive caffeine can stimulate the heart and lead to a rapid heart rate (tachycardia) and elevated blood pressure. This can be especially concerning for individuals with preexisting heart conditions.
  • Digestive Issues: Caffeine can act as a mild irritant to the gastrointestinal tract, potentially causing stomach discomfort, acid reflux, or even more severe digestive problems in some individuals.

What constitutes excessive caffeine intake can vary from person to person, but generally, consuming more than 400 milligrams of caffeine per day (equivalent to about four cups of brewed coffee) can increase the risk of experiencing negative side effects. Individual tolerance to caffeine can also change over time, so paying attention to how caffeine affects you and adjusting your consumption accordingly is important. If you have any underlying medical conditions or concerns about caffeine's impact on your health, it's advisable to consult with a healthcare professional.

What is the Caffeine Content of Coffee?

The caffeine content of coffee can vary widely depending on several factors, including the type of coffee bean, the brewing method, the serving size, and the brewing time. These variables make it challenging to gauge how much caffeine is in any given cup of coffee. Here are some approximate caffeine levels for common types of coffee:

  • Brewed Filter Coffee: On average, a 240ml cup/mug of brewed coffee contains about 95 milligrams of caffeine. However, this can range from 70 to 140 milligrams or more, depending on factors like the coffee blend and brewing method.
  • Espresso: Espresso is known for its concentrated caffeine content. A single shot (approx 30ml) of espresso typically contains about 63 milligrams of caffeine; a double shot, therefore, has approximately 126mg of caffeine. Any milky coffee made with espresso (Cappuccino, Latte, etc.) will have these same numbers.
  • Instant Coffee: Instant coffee usually contains slightly less caffeine than brewed coffee. A 250ml cup of instant coffee typically contains around 63 milligrams of caffeine, but this can vary from brand to brand.
  • French Press Coffee: French press coffee can have a caffeine content similar to filter coffee, around 70 to 140 milligrams per 250ml cup, depending on the coffee bean and brewing time.
  • Cold Brew Coffee: Cold brew coffee tends to have a higher caffeine content than regular brewed coffee due to its extended brewing time. A 250ml cup of cold brew coffee can contain around 100 to 200 milligrams of caffeine or more.

It's important to note that these figures are approximate and can vary based on many factors. Additionally, coffee shop servings can vary in size, so the caffeine content in a coffee shop drink may differ from standard measurements.

Is it Possible to Overdose on Caffeine?

Yes, too much caffeine can indeed be toxic and even lethal. But the good news is that it's hard to do through coffee alone. Any cases of fatalities have involved caffeine pills or medications that contain caffeine. Reaching toxicity means ingesting 10g of pure caffeine, equating to drinking between 50-100 cups of coffee in one day. While some days may make us feel like consuming that amount is necessary, in reality, it isn't easy to do. The current advice is for adults to consume no more than 400mg per day, with that number falling to 200mg if you're pregnant.