Is it possible to overdose on caffeine? Properties and effects on the body

For many people, starting the day without a cup of hot coffee is unimaginable. The caffeine contained in coffee stimulates circulation, increases motivation and has a positive effect on mood. Because caffeine has a stimulating effect, it helps us overcome minor and major fatigue. So let's take a closer look at caffeine. What is caffeine and how does it work, where can we find it besides coffee, and is it possible to overdose on it?

Caffeine – what exactly is it?

Caffeine is a stimulating substance. It occurs naturally in the leaves and seeds of many plants. On the other hand, this substance can also be produced in laboratory conditions and processed into stimulant supplements.

In medical terminology, caffeine itself is considered a psychoactive substance because it can stimulate the central nervous system, increasing the body's alertness. However, it should not be mistakenly identified with substances such as alcohol, as caffeine, despite the risk of side effects at higher doses, also belongs to the so-called nootropic drugs, i.e. substances that particularly improve cognitive functions, including memory and motivation in healthy individuals.

In its natural form, caffeine is bitter to the palate and reaches its maximum concentration in the blood within an hour of consuming the first cup of coffee. The effects of the substance can last up to six hours. It is estimated that 80 to 90% of the world's population consumes products containing caffeine on a daily basis. In Poland alone, approximately 60% of adults drink coffee every day.

Caffeine in nature – where is it found?

Caffeine is found in leaves, nuts, flowers and fruits all over the world. Plants containing caffeine are harvested from natural crops and then processed into products that we see every day on shop shelves or in our homes. The largest crops in the world are often coffee or black tea, plants that contain large amounts of caffeine.

Here are some of the most commonly consumed natural products that contain caffeine:

• Coffee
• Cocoa
• Yerba Mate
• Tea
• Guarana
• Kola nuts

Caffeine tablets – what is worth knowing about them?

Caffeine tablets are dietary supplements based on caffeine. Some contain natural caffeine, extracted, for example, during the coffee brewing process. Others may contain synthetic forms of the substance.

When taken as recommended, caffeine tablets provide a number of benefits associated with caffeine. Like all caffeine-based preparations, tablets are a relatively safe substitute for your morning cup of coffee.

It is a particularly recommended substitute for natural caffeine for people who do not like drinks made from natural plants containing caffeine. They are also recommended for people who practise all kinds of sports. One tablet containing 100 to 200 mg can improve the body's psychomotor performance, thereby increasing resistance to training-induced stress.

Anhydrous caffeine – how does it work?

Anhydrous caffeine is extracted from green tea leaves, coffee beans or cocoa beans. The remaining plant substances and water are filtered in a laboratory environment, leaving a white crystalline powder called anhydrous caffeine for our use.

Anhydrous caffeine works in the same way as naturally occurring caffeine. It mimics the neurotransmitter adenosine, which is present in the brain. As a result, it causes a feeling of stimulation or increased motivation similar to that of coffee.

However, it is important that anhydrous caffeine preparations are consumed in accordance with the manufacturer's recommendations. Due to its high concentration of active substance, powdered caffeine should be consumed in small amounts, as it is very easy to accidentally exceed the recommended dose.

Properties of caffeine – what are they?

Caffeine consumption is associated with a number of health benefits related to its properties. These include:

• Liver protection – caffeine can reduce the risk of liver damage (cirrhosis) by up to 84%. It can slow down the progression of the disease, improve response to drug treatment and reduce the risk of premature death. Anti-ageing effects of caffeine – drinking caffeinated beverages reduces the risk of premature death by 30%, especially in women and people with diabetes.
• Reduces the risk of cancer – 2-4 cups of coffee a day can reduce the risk of liver cancer by 64% and the risk of colon cancer by up to 38%. All thanks to the antioxidant effect of the substance, which supports the body's regenerative processes.
• Protects the skin – regular caffeine consumption can reduce the risk of skin cancer by 20%
• Reduces the risk of multiple sclerosis – some studies suggest that the antioxidant properties of caffeine may intervene in reducing the risk of developing multiple sclerosis.
• Supports healthy bowel function – caffeine, a stimulant, promotes proper bowel movement. It also increases the number and activity of beneficial intestinal bacteria.

It is worth knowing that caffeine, when combined with the active substances in coffee, green tea or yerba mate, has significantly greater health-promoting properties. Thus, some of the benefits mentioned above may also be caused or intensified by the synergistic effect of other plant substances with caffeine itself.

The effects of caffeine on the human body

Caffeine begins to affect the human body 35 to 45 minutes after consumption. It is absorbed by the stomach and small intestine, and from there it enters the bloodstream, which then distributes it throughout the body.

The main effect of caffeine is primarily on the central nervous system. Its structure is similar to a neurotransmitter called adenosine, which is produced by the human body itself. The role of adenosine is to induce fatigue in the body after strenuous physical and mental exertion. To do this, the neurotransmitter settles in specific receptors in the brain, which then switch off their activity.

Due to its similarity, caffeine binds to the above-mentioned receptors, which adenosine cannot dock to. The result is a reduced feeling of fatigue and stimulation of the circulatory system. The body begins to work even faster, and metabolism, heart rate, pulse and breathing accelerate after caffeine consumption.

The organs are supplied with blood more quickly and the body is ready for action in a shorter time. In addition, the secretion of the stimulating hormones cortisol and adrenaline also increases. Furthermore, caffeine increases physical and mental performance, improving, among other things, the ability to react quickly.

Caffeine overdose – what are its characteristics?

We talk about a caffeine overdose when a dose of one gram, or 1000 milligrams, has been consumed. An overdose is characterised by a significant increase in heart rate and additional contractions, which can cause the heart to beat outside its normal rhythm.

Too much caffeine at the time of overdose also leads to a significant increase in anxiety and insomnia. In the worst case, an overdose can cause serious circulatory collapse. It should be noted that elderly people, children or people who do not consume caffeine regularly may experience symptoms of overdose even with small amounts.

Caffeine itself is only lethal in very high doses. In adults, this is approximately 10 g, and in children, 5 g. This amount of caffeine corresponds to approximately 65 or 30 cups of coffee, if the caffeine content is particularly high.

Side effects of caffeine – are they dangerous?

Caffeine consumption is generally considered safe. The recommended daily dose of caffeine for adults is between 200 and 400 mg. However, it is worth remembering that some people may experience discomfort associated with caffeine consumption, mainly due to reduced adenosine activity in the central nervous system.

Some side effects associated with excessive caffeine consumption include:

• Nervousness
• Anxiety
• Panic attacks
• Tremors
• Sweating
• Irregular heart rate
• Sleep problems
• Headaches

In addition, caffeine can easily cross the placenta, which is associated with a significant risk of miscarriage or low birth weight. Pregnant women should limit their caffeine intake or avoid it altogether. The same applies to children and elderly people with high blood pressure.

References

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Caffeine – G. A. Spiller, CRC Press, 1998.

Caffeine and Health Research – K. P. Chambers, Nova Biomedical Books, 2009.

Caffeine and Activation Theory: Effects on Health and Behaviour – B. D. Smith, U. Gupta, B. S. Gupta, CRC Press, 2006.

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