Why more and more young people cannot live without "life-saving coffee" every day?

Audit expert: Yin Tielun

Deputy Chief Physician, Department of Neurology, Airport Branch, Peking University Third Hospital

Nowadays, whether in first-tier or second-tier cities or third-tier or fourth-tier small towns, you can see a coffee shop within a dozen minutes' walk, and many of my colleagues and friends have drunk coffee to some extent. Coffee is one of the three major beverages in the world, and it has received more and more attention and love in recent years. As we all know, drinking coffee helps to refresh the mind, so how does it work? What kind of coffee is healthier? Let's take a look at the "secret secret of coffee".

Coffee source | pixabay

1How does coffee refresh you?

You should know that after a series of physical and mental labor, the human body will produce a neurotransmitter called "adenosine". This neurotransmitter can bind to the adenosine receptors in the human body; when the number of adenosine bound to the adenosine receptors is large enough, they will begin to transmit fatigue signals to the brain. After the brain receives the signal, it will inhibit nerve excitement, so we will feel tired. The key to coffee's ability to refresh is its main ingredient - caffeine. Caffeine is a methylxanthine alkaloid compound. Its chemical structure is very similar to that of adenosine and can compete for central adenosine receptors. When we drink coffee, caffeine enters the human body and it will replace adenosine to bind to adenosine receptors , which is equivalent to occupying the position originally belonging to adenosine.

Caffeine (C) replaces adenosine (A) in binding to adenosine receptors (AR) Source | sleepopolis.com

If adenosine cannot bind to adenosine receptors, it will not release fatigue signals to the brain, and we will not feel tired. However, it should be noted that although adenosine is squeezed out by caffeine, it does not mean that it is metabolized by the human body. In fact, adenosine will remain in the human body until the caffeine is metabolized, and then adenosine will re-bind to the adenosine receptors. Therefore, the effect of drinking coffee to refresh is only temporary, and it only treats the symptoms but not the root cause . If the body does not get rest, fatigue will sooner or later sweep in. In addition, the metabolism of caffeine is mainly completed by an enzyme called "CYP1A2" in the liver. The activity of this enzyme varies in different human bodies, so the metabolic efficiency of caffeine varies from person to person. After some people drink coffee, caffeine is metabolized very quickly, and caffeine is excreted from the body before it has time to play a role, so this type of people do not have much effect of drinking coffee to refresh themselves .

Coffee source | pixabay

2Why do people who exercise regularly like to drink coffee?

In 2008, researchers asked 20 subjects to drink different drinks in the same exercise environment simulated in the laboratory to test their exercise effects. The results showed that those who supplemented with carbohydrates and caffeine at the same time had better batting performance and alertness than those who only supplemented with carbohydrates. Therefore, for those who exercise and keep fit, drinking coffee can improve their athletic ability to a certain extent . Before 2003, caffeine was once a "banned drug" for athletes. If they were found to have excessive caffeine in the arena, they would even be disqualified. Of course, this ban has now been lifted.

For most ordinary people, they can drink coffee in moderation for better athletic performance. Drinking coffee can not only refresh the mind and increase the effect of exercise, but it also has a great effect, which is to help us lose fat! A study measured the body temperature of the subjects after drinking coffee and found that after the subjects drank coffee, the temperature of the brown fat area in the body increased significantly .

The picture on the right shows that after the subjects drank coffee, the body temperature in the neck (the main distribution area of ​​brown fat in the human body) increased significantly Source | Caffeine exposure induces browning features in adipose tissue in vitro and in vivo

Brown fat is one of the two types of fat in the human body. Its main function is to promote the consumption of fat and sugar . The other type of fat is called white fat, which mainly stores energy. Therefore, caffeine can activate brown fat to a certain extent, which helps to accelerate the burning of body fat. One thing to note is that the coffee mentioned here refers to black coffee , that is, pure coffee with no other sugar or milk added, only coffee and water.

American coffee source | pixabay

3. Caffeine’s Multiple Identities

In addition to being used for refreshing and reducing fat, caffeine has many other functions. We all know that coffee beans contain caffeine, but other natural plants such as tea leaves and cocoa beans also contain caffeine. Therefore, the chocolate and tea we consume daily contain caffeine. In addition, caffeine is also used as a food additive and is added to functional drinks, cola, soda water, and chewable vitamin tablets.

The source of caffeine in a certain functional beverage | A shopping website

Caffeine is also an important neurostimulant. A large number of studies have shown that caffeine can prevent or treat certain central nervous system diseases, such as Parkinson's disease, Alzheimer's disease, hypoxic-ischemic encephalopathy, neuroinflammatory reactive diseases, etc. The pharmacological effects of caffeine in the treatment of different diseases are very complex. Different doses and intakes will produce different effects, which still need further research. So, since caffeine is so helpful to human health, can we drink a lot of it? At present, the obvious disadvantage of caffeine is that it can easily lead to calcium loss . If you consume too much caffeine, it may aggravate osteoporosis in the human body. Apart from this, no research has shown that consuming caffeine will have serious adverse effects.

Coffee source | pixabay

Some people may say that the symptoms of palpitations and heart discomfort after drinking coffee do not mean that caffeine has adverse effects on cardiovascular system? In fact, caffeine promotes the release of "norepinephrine" from the sympathetic nerve endings in the human body, which in turn leads to faster heart rate , but this effect disappears after a period of time. Therefore, if caffeine is consumed normally, it will not have much effect on the human body. China has no clear regulations on caffeine intake. Internationally, the European Food Safety Authority recommends that healthy adults should consume less than 200 mg of caffeine at a time and should not consume more than 400 mg of caffeine throughout the day, which is about the amount of 2 cups of American coffee .

In general, coffee is good, but if drinking coffee makes you feel very uncomfortable, don't force yourself to drink it. If you like drinking coffee and have no discomfort, it is recommended not to exceed 400mg of coffee per day. You can also take some calcium and vitamin D to maintain a healthy body.