How does caffeine make you excited? It's a plant pesticide, but it's hard to quit

In a corner of the city, we looked at the work in our hands tiredly and drank another cup of warm coffee.

The coffee is absorbed into your body through your intestines, and your attention gradually becomes focused, and the feeling of excitement lingers.

This magical experience makes us increasingly addicted to it, and we can’t be happy without drinking it when we are tired.

For us, the slightly bitter taste of coffee can always snatch time away from sleepiness.

In fact, the caffeine contained in coffee is the main contributor to refreshing the brain.

As the most popular psychiatric drug, it is not only not rejected, but also gathers a large number of people to become its supporters.

Coke, tea, coffee, medicines, chocolate, various energy drinks, endless stream of products have already penetrated into our lives.

Coffee tasting

Going back to the origin, the Chinese Shennong discovered tea from a leaf that fell into hot water.

At this time, the Native Americans on the other side of the ocean happened to use holly as a tea substitute to make black holy water.

The unusual vitality of several sheep in Ethiopia, Africa after accidentally eating coffee beans also aroused people's curiosity.

At almost the same time, caffeine was turned into beverages in the three continents of Asia, Africa and America.

Tea substitute holly

Our ancestors, who had insufficient knowledge of nature, were always full of doubts about these things that could refresh the mind.

However, after 1819, scientists gradually unveiled the mystery of caffeine.

German chemist Runge first extracted pure caffeine from coffee beans, and then E. Fischer, also a German chemist, successfully synthesized caffeine.

The vigorous development of modern medicine has allowed people to gradually understand the properties of alkaloids such as caffeine.

Coffee Beans

It turns out that there are adenosine and adenosine receptors in the central part of the human brain that are specifically responsible for responding to fatigue.

When the human body's physical energy is exhausted, only by combining adenosine with adenosine receptors to transmit the body's information to the brain can the brain feel tired and send out a signal that it needs sleep.

However, caffeine can easily cross the blood-brain barrier and, with a structure similar to adenosine, sneakily bind to adenosine receptors.

After caffeine actively competes for the receptors, the adenosine signal cannot be transmitted to the brain, and it can only stand by and worry.

Molecular formula of caffeine

In addition, caffeine increases dopamine levels through more complex neural mechanisms.

When the brain is unable to sense sleepiness, the increase in dopamine levels makes the user feel more alert and excited.

Studies have also shown that caffeine not only acts on nerves, it can also lower the threshold of endorphins and cortisol *, thereby enhancing a person's endurance.

It also improves neuromuscular transmission and alters intracellular calcium concentrations to enhance the contractility of muscle fibers.

This is helpful for increasing instantaneous burst or improving endurance, so many functional drinks contain caffeine.

However, the instantaneous increase is not conducive to maintaining neuromuscular stability, and some sports that require precision are not suitable for the use of caffeine.

*Note: Endorphins can relieve the soreness caused by fatigue, while cortisol promotes energy release.

Caffeine can also be used as a medicine. It can tighten the blood vessels in the brain and reduce blood flow to the brain. It can be used as a "miracle medicine" to relieve headaches.

At the same time, it can also promote the synthesis and release of catecholamines*, so it can be used as a positive cardiovascular drug.

Even a small dose taken at one time can produce positive psychological effects such as increased heart rate and blood pressure.

Some studies also believe that caffeine is beneficial in preventing type 2 diabetes and is also effective in preventing Parkinson's disease.

*Note: Catecholamines include norepinephrine (NAd), epinephrine (Ad), and dopamine (DA). The secretion of catecholamines can increase blood pressure and increase heart rate.

Caffeinated headache medicine

But why do plants produce so much powerful caffeine?

Could it be that, like fruits, the purpose is to attract animals and make them addicted to spreading their seeds?

In fact, caffeine is the plant’s own secret weapon, with many magical effects.

To repel insects, some plants secrete caffeine to protect themselves.

Caffeine can cause insects to become anorexic after ingesting it, and in large doses it can even cause death.

Spiders can't even weave a web properly when they're addicted to caffeine

Plants use caffeine not only to repel pests, but also to attract bees for precise pollination.

Because caffeine can enhance bees' long-term memory of plants, it greatly increases the possibility of bees going back and forth to collect nectar on the same plants.

If leaves containing caffeine fall to the ground, the caffeine enters the soil and can inhibit the growth of surrounding plants that compete with it.

The fact that animals treat caffeine as food is definitely something that plants never expected .

Of course, it is not just caffeine that has suffered. Many alkaloids have had such experiences. For example, nicotine is used as an insecticide in farmland, ephedrine is used as a cold medicine, berberine in berberine, etc., are all alkaloids that have been brought into human society.

It can be said that alkaloids are a discovery no less important than penicillin.

Pure caffeine is white, not the black color of coffee.

As a pesticide that plants use to protect themselves, caffeine is certainly not created to help humans.

Caffeine, as a psychotropic drug, can cause dependence. When you try hard to quit it, you will experience withdrawal symptoms such as headaches, fatigue, and irritability .

Although this is much better than drug withdrawal reactions, many accidents are often caused by ignoring these possible problems.

News of the day

At the end of 2015, Japan's NHK TV station reported a case in which a 20-year-old man died of caffeine poisoning due to excessive intake.

This young man works at a gas station. Because he often works day and night, he often drinks energy drinks as a daily refreshment to stay awake.

Perhaps the refreshing effect was not obvious enough, so he also took drugs containing caffeine, and eventually died from excessive caffeine intake in a short period of time .

If you continue to take large doses to maintain your mental state, death is not far away.

Data shows that the lethal oral dose of caffeine for adults is generally 10g, a value that is easily reached only when consuming the pure product directly.

According to the average 130~240mg of caffeine in 500ml of coffee on the market (the amount of caffeine in instant coffee is relatively lower), drinking 20 liters of coffee would reach the lethal dose, and the probability of dying from overeating would be even greater.

However, according to the standards given by the FDA, a safe dose is 400 mg per day. Exceeding the dose will lead to dependence or even addiction. Once discontinued, symptoms such as mental depression and general fatigue will appear .

Caffeine content of coffee and tea, pay attention to volume

But it is not enough to be cautious about the lethal dose, because caffeine does not reawaken people's vitality, but rather pre-empts future vitality .

When many people feel sleepy, they will consider drinking coffee continuously in order to get rid of the unpleasant micro-sleep phenomenon such as drooping eyelids.

Caffeine lived up to expectations and inhibited the binding of adenosine to adenosine receptors, but adenosine did not disappear.

Adenosine queues up next to the adenosine receptors waiting to bind, and the human body's fatigue is only masked by caffeine. In fact, the fatigue is still accumulating, and adenosine accumulates more and more.

When the effect of caffeine wears off, far more adenosine than normal binds to adenosine receptors, causing extreme fatigue. This is known as "caffeine crash."

Moreover, the safe dose of 400 mg may not be suitable for everyone.

Europeans and Americans have a long coffee culture and their coffee tolerance is higher than that of Asians to a certain extent.

If your parents can drink two large cups of coffee without batting an eyelid, that means your tolerance isn't too bad.

But some people only need a small cup to fight off a whole night of sleep, so the dosage still varies from person to person .

While it's bad enough that coffee drinking has risks, it's even worse: That "high" might not be what you want .

Caffeine can effectively alleviate the attention deficit caused by lack of sleep, but this is only helpful for simple and boring overtime work.

In jobs that require more judgment and thinking, caffeine can no longer mask the lack of risk perception caused by lack of sleep.

Serious cognitive biases will make the final work results unsatisfactory, which will be no different from you forcing yourself to do things.

Moreover, after staying up all night, the metabolism of caffeine in the body will affect the subsequent restorative sleep.

The time it takes to metabolize caffeine in the body is also affected by individual differences. Generally speaking, the half-life of caffeine in adults is about 5 to 6 hours.

Lifestyle habits can also affect the time of metabolism. Pregnant women and alcoholics have relatively slow metabolism, while smokers have a faster metabolism.

If the body's metabolism is incomplete, sleep quality is often poor, and if you still consume caffeine to maintain your energy, you will fall into a vicious cycle .

*Note: This refers to the time it takes for half of the caffeine to be metabolized.

There is also data showing that even after caffeine’s half-life has expired, the quality of restorative sleep may still be affected.

So the greatest help that caffeine can provide to people is actually not as useful as imagined. If you have a choice, it is better to get some sleep .

As for caffeine, there is no need to be afraid of it.

After all, caffeine has long been a part of beverage culture. Functional drinks, cola, milk tea, coffee, and tea drinks, which one of them is not seen every day?

Among those scientists and researchers who debate the pros and cons of caffeine every day, which one of them is not working day and night in the laboratory drinking coffee?

Instead, we watch the news reports with fear all day long, but never care about the dosage.

*References

McHill, AW, Smith, BJ, & Wright, KP. Effects of caffeine on skin and core temperatures, alertness, and recovery sleep during circadian misalignment. Journal of biological rhythms, 2014. 29(2), 131-143.

Zhai Jinxiao, Cui Wen, Zhu Jun. Research progress on caffeine intoxication, detection and application[J]. China Forensic Identification, 2017, (05): 30-35.

Li Haixia, Chen Rong, Zhou Dan, Wu Liang. Research progress on the synthesis and pharmacological effects of caffeine[J]. West China Journal of Pharmaceutical Sciences, 2011, 26(02): 182-187.

Yi Chaoran, Wei Zhongqing. Pharmacological effects and applications of caffeine[J]. Journal of Medical Postgraduates, 2005, (03): 270-272.