Coffee does not produce energy, it is just a transporter of energy.

Coffee is native to north-central Africa and belongs to the Rubiaceae family. It has been consumed by humans for more than 3,000 years . It is one of the most popular beverages in the world. About 80% of Europeans and Americans have the habit of drinking coffee every day. The consumption of coffee in the Chinese market is also increasing year by year. People are keen on the refreshing effect of coffee, and the rich aroma is intoxicating.

The refreshing effect of coffee comes from the alkaloids in coffee beans, the most representative of which is caffeine . From the perspective of biological evolution, caffeine was originally a bitter and toxic chemical in plant fruits, used to protect plants from being eaten by animals . Many animals will be poisoned by consuming coffee, but primates have a strong detoxification ability in their livers due to long-term consumption of plant fruits.

☆Caffeine does not produce extra energy, but advances energy

The chemical structure of caffeine is very similar to adenosine in the human body, which is a product of energy metabolism. Adenosine is continuously produced from cells and secreted outside the cells. When it binds to the adenosine receptors on the cell membrane, it tells the cells: "The energy consumption is almost complete, I am tired and need to rest."

When people are awake, the adenosine on nerve cells increases every hour, and when it reaches a certain amount, they will feel sleepy. However, if you drink coffee at this time, it will cause caffeine to bind to adenosine receptors and occupy the binding sites of adenosine. But caffeine is not adenosine after all. After it binds to adenosine receptors, it does not trigger signal transduction in cells, so it will not cause sleepiness. At this time, adenosine is still being produced in human cells. Since it cannot bind to receptors on the cell membrane, it wanders in the intercellular space. After about four or five hours, the caffeine is metabolized by the human body, and the accumulated adenosine will occupy almost all adenosine receptors, and people will feel even sleepier. From this perspective, caffeine pre-empts people's energy instead of generating extra energy.

☆ Long-term drinking will cause reverse regulation

After long-term coffee drinking, adenosine receptors will be reversed and the expression level on nerve cells will increase. The human body gradually becomes tolerant to caffeine, and the initial high energy level will not be obvious after getting used to it. When habitual coffee drinkers quit coffee, their mental state and cognitive ability will decline, and they need to consume the same dose of coffee as usual to return to normal levels. In this way, drinking coffee to improve learning or work efficiency is not worth the loss, because you have to drink a certain amount every day to maintain normal energy, otherwise it is worse than normal.

I believe some coffee lovers will consider quitting coffee after seeing this conclusion. After a period of abstaining from coffee, the expression level of adenosine receptors in the human brain will return to normal, returning to the state before coffee addiction. Coffee is indeed an addictive substance, but it has no obvious physical and mental harm and withdrawal symptoms compared to drugs, which is why it can be a legally available commodity.

In addition to caffeine, coffee also contains hundreds of chemical substances such as sugars, organic acids, esters, sterols, diterpenes, etc., which regulate human functions in many aspects. The pros and cons of coffee on health have always been controversial. Scientists have compiled research reports on the relationship between coffee and health since the 1970s and concluded that: under the premise of moderate consumption, the benefits of coffee to the human body are slightly greater than the harm, and it can reduce the incidence of senile dementia and certain cancers. The harm is that it can easily cause difficulty in pregnancy in women and lead to osteoporosis.

☆It is recommended not to exceed two cups per day

Should you drink coffee? The answer varies from person to person. If you are attracted by the unique taste and aroma of coffee, and your love for coffee is deep in your bones, you don't have to deliberately reject its temptation. If you want to rely on coffee to refresh yourself, it is better to drink it occasionally at certain important moments to help you perform at an extraordinary level. It is said that some athletes do this. Coffee is not a banned stimulant. The upper limit of caffeine in urine tests in sports competitions is 12 micrograms per milliliter.

The effect of coffee on the human body is closely related to the dosage. The European Food Safety Authority recommends not to drink more than 400 mg of caffeine per day, which is about two cups of coffee. It is worth noting that for children and adolescents, since their brains are not yet fully developed, caffeine intake has a stronger stimulation on the nervous system. Therefore, experts in the field of educational neuroscience oppose minors to drink coffee. The medical community believes that people with insomnia, hyperthyroidism, digestive system diseases, cardiovascular diseases, and pregnant women should drink less or no coffee .

Finally, I would like to remind everyone that coffee is not the only source of caffeine. Caffeine is also found in tea, cocoa, Coca-Cola, and chocolate . If you are addicted to these foods, you should limit the total amount of intake.

Source: Popular Science Times

Author: Wang Xin (Associate Professor of Central China Normal University, Member of the Science Popularization and Continuing Education Committee of the Chinese Society of Neuroscience)