How much do you know about the health benefits of coffee?

Author: Zhang Yu, researcher at Chinese Center for Disease Control and Prevention, master's supervisor

Reviewer: Fu Rui, Chief Physician, Beijing Century Altar Hospital, Capital Medical University

The word coffee comes from Arabic, which means plant beverage. Later, it gradually evolved into a drink made by mixing roasted and ground coffee beans with water. The reason why coffee is so popular is not only because of its unique taste, but also because it can bring pleasure and refresh the mind. Coffee contains caffeine, tannin, fat, protein, carbohydrates, minerals, and trace amounts of lime. It is the interaction of complex ingredients that makes different types of coffee show different sweetness, acidity, aroma and purity in taste.

Caffeine is the most important active ingredient in coffee and also the main source of bitterness. It is a xanthine alkaloid compound. A moderate intake can stimulate the central nervous system, help people stay awake, and improve concentration and thinking ability. The bitterness of coffee is also mostly due to the taste of caffeine. In addition, coffee also contains a variety of mineral components, such as potassium, magnesium, zinc and chromium, which are also very beneficial to the body's metabolism and various physiological functions.

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The health effects of coffee are all based on moderate drinking, so how much is considered moderate?

This mainly depends on the caffeine content in the coffee. Generally speaking, if a normal person consumes more than 400 mg of caffeine at a time, the risk of discomfort symptoms will increase significantly. Therefore, it is recommended that the daily caffeine intake should be controlled below 400 mg. Taking instant coffee as an example, the caffeine content of each serving (usually a small bag or a cup) is 50 to 70 mg, so it is not advisable to drink more than 6 servings a day. For hand-brewed coffee, the caffeine content of each cup is about 100 mg, so it is more appropriate to drink 3 to 5 cups a day.

In addition, the amount of coffee you drink every day is also related to factors such as your weight and the type of coffee you drink. People who are lighter are advised to reduce their coffee intake accordingly; if you are drinking espresso, which has a high caffeine content, you should also reduce your coffee intake appropriately. In addition to coffee, many daily drinks such as cola, tea, and milk tea also contain caffeine, so after drinking these drinks, remember to reduce your coffee intake.

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My heart rate increases after drinking coffee. Is this a heart attack?

An increased heart rate after drinking coffee does not directly indicate heart disease, but this phenomenon still needs to be taken seriously. The caffeine in coffee can stimulate the central nervous system, causing a significant increase in heart rate, increased myocardial contractility, vasodilation and increased blood flow, as well as increased respiratory rate and gastrointestinal motility. The extent of these physiological reactions varies from person to person and is affected by the individual's tolerance to coffee and the concentration of the coffee consumed. For example, people who drink coffee regularly may not feel anything at all, but people who are intolerant to caffeine may feel panic, palpitations, dizziness and discomfort. Moreover, the higher the concentration of coffee, the more obvious the symptoms will be. Therefore, while enjoying the refreshing effect of coffee, you also need to pay attention to your own body's reactions and drink in moderation.

So if you drink too much coffee, will it really cause heart disease?

Moderate coffee consumption does not usually increase the risk of cardiovascular and cerebrovascular diseases, but long-term excessive coffee consumption may increase the risk of cardiovascular system diseases.

On the one hand, large amounts of caffeine intake will increase the burden on the heart and may induce cardiovascular disease. This is because high doses of caffeine will significantly increase heart rate and blood pressure, put pressure on the cardiovascular system, and increase the risk of arrhythmia or irregular heartbeat. The increase in heart rate will lead to an increase in myocardial oxygen consumption, and arrhythmia may also cause insufficient blood supply to the heart, all of which will increase the risk of coronary heart disease, myocardial infarction and other diseases.

On the other hand, excessive coffee intake can also cause blood vessels to constrict, leading to insufficient blood supply to organs. Certain acidic substances and caffeine in coffee have the effect of constricting blood vessels, which may reduce blood flow to major organs of the body, causing ischemia and hypoxia, thereby increasing the risk of heart attack and stroke.

In addition, excessive coffee consumption may accelerate hardening of blood vessels and increase the risk of atherosclerosis.

Does drinking coffee cause osteoporosis?

Drinking coffee is only a risk factor for osteoporosis, not a direct cause of the disease. Drinking coffee in moderation does not directly lead to osteoporosis. Although ingredients such as caffeine and oxalic acid in coffee may affect calcium absorption and increase calcium loss, this effect is relatively limited. There is a dynamic balance in calcium metabolism in the human body. When the amount of calcium excreted through urine and other pathways increases, the intestines will increase the calcium absorption rate accordingly to compensate for the loss. Therefore, as long as you maintain a balanced diet, drinking coffee in moderation will not lead to calcium deficiency.

Is coffee really addictive?

Coffee is indeed addictive, but its withdrawal reaction usually does not cause long-term physical and mental effects. Long-term coffee drinking can make the body mildly dependent on caffeine, because caffeine can stimulate the brain to produce mild euphoria, and bind to adenosine receptors in the brain, so that the activity of neurons "does not decay", making people feel relieved from fatigue. When the daily caffeine intake exceeds 100 mg, the body may become dependent. If you stop consuming caffeine for 12 to 24 hours, you may experience symptoms such as headache, fatigue, anxiety, and inability to concentrate, which is called "caffeine withdrawal." However, this reaction is different from the persistent reaction produced during withdrawal from drugs and psychotropic drugs. Most people can recover within 2 to 3 days.

Who is not suitable for drinking coffee?

Although coffee can bring physical and mental pleasure, it is not suitable for everyone. Coffee is not recommended for children and adolescents who are in an important period of physical and neurological development, people who are sensitive to caffeine, people with long-term insomnia, people with gastrointestinal diseases and osteoporosis. Coffee may also affect the absorption of iron in food, so patients with iron deficiency anemia should also avoid drinking it. Pregnant women should also be cautious when drinking coffee, and it is recommended not to exceed 1 cup per day. Coffee should also not be taken with ephedrine cold medicines to avoid symptoms of "overdose".

In addition, for people who often stay up late and work overtime, it is unrealistic to try to "extend life" by drinking coffee. Coffee can only provide a short-term brain excitement. Increasing the amount of coffee will not only lead to caffeine dependence, but may also aggravate mental anxiety and insomnia. Therefore, it is recommended to consider the long-term perspective and give the brain and body enough rest.