关于咖啡的健康知识您了解多少？ How much do you know about the health knowledge of coffee?

咖啡之所以深受喜爱，除了其独特的味道外，更在于它能带来愉悦感及提神醒脑的功效。咖啡中含有咖啡因、丹宁酸、脂肪、蛋白质、碳水化合物、矿物质，以及微量石灰等成分。正是复杂成分的相互作用，使得不同种类的咖啡在味觉上展现出各异的甜度、酸度、香醇度与纯净度。

咖啡因作为咖啡中最为关键的活性成分，同时也是苦味的主要来源。它是一种黄嘌呤生物碱化合物，适量摄入能刺激中枢神经系统，帮助人们保持清醒，提升注意力和思维能力。咖啡的苦涩感也多源于咖啡因的味道。此外，咖啡中还含有多种矿物质成分，如钾、镁、锌和铬等，这些矿物质对身体的新陈代谢和各项生理功能也有很大的助益作用。

咖啡的健康效应都是建立在适当饮用基础上，那么，究竟多少才算适量呢？

这主要取决于咖啡中咖啡因的含量。一般而言，正常人若一次性摄入超过400毫克的咖啡因，出现不适症状的风险会明显增加。因此，建议每日摄入咖啡因的量应控制在400毫克以下。以速溶咖啡为例，每份（通常指一小包或一杯的量）的咖啡因含量为50～70毫克，所以每日饮用不宜超过6份。而对于手冲咖啡，其每杯的咖啡因量约为100毫克左右，因此每日饮用3～5杯较为适宜。

此外，每日咖啡的饮用量还与个人体重、咖啡种类等因素存在一定的相关性。体重较轻的人建议相应减少饮用量；若饮用的是咖啡因含量较高的意式浓缩咖啡，也应适当减少饮用量。除了咖啡，许多日常饮品如可乐、茶、奶茶等也含有咖啡因，因此在喝了这些饮料后，也要记得减少咖啡的饮用量。

喝完咖啡之后心跳加快，这是心脏病吗？

喝完咖啡后心跳加快，并非直接表明患有心脏疾病，但这一现象仍需引起重视。咖啡中的咖啡因能够刺激中枢神经系统，导致心率明显加快，心肌收缩力增强，血管扩张并促进血流速度加快，同时还会增加呼吸频率和胃肠道蠕动速度。这些生理反应的程度因人而异，受个体对咖啡的耐受性以及所饮咖啡浓度的影响。例如，经常喝咖啡的人可能对此一点感觉都没有，但对咖啡因不耐受的人则会觉得心慌、心悸、头晕不适。而且，咖啡浓度越高，症状就会越明显。因此，在享受咖啡带来的提神效果时，也需留意自身的身体反应，适量饮用。

那如果咖啡喝多了，真会诱发心脏疾病吗？

适量饮用咖啡通常不会增加患心脑血管疾病的风险，但长期过量饮用则可能增加心血管系统疾病的风险。

一方面，大量咖啡因的摄入会增加心脏负担，可能诱发心血管疾病。这是因为高剂量的咖啡因会显著提高心率和血压，给心血管系统带来压力，进而增加心律失常或心跳不规则的风险。而心率的增加又会导致心肌耗氧量上升，心律失常还可能引发心脏供血不足，这些都会增加发生冠心病、心肌梗死等疾病的风险。

另一方面，过量咖啡摄入还会使血管收缩，导致脏器供血不足。咖啡中的某些酸性物质和咖啡因均具有收缩血管的作用，这可能使身体主要脏器的血流减少，出现缺血缺氧的情况，进而增加心脏病发作和中风的风险。

此外，过量饮用咖啡还可能加速血管硬化，增加动脉粥样硬化的风险。

喝咖啡会导致骨质疏松吗？

喝咖啡只是骨质疏松的一个危险因素，而非直接致病因素。适量饮用咖啡并不会直接导致骨质疏松。尽管咖啡中的咖啡因和草酸等成分可能会影响钙的吸收，增加钙的流失，但这种影响相对有限。人体内的钙代谢存在着动态平衡，当通过尿液等途径排泄的钙增多时，肠道会相应提升钙的吸收率来弥补损耗。因此，只要保持饮食均衡，适量喝咖啡并不会导致钙缺乏。

咖啡真的会让人上瘾吗？

咖啡确实具有一定的成瘾性，但其戒断反应通常不会对身体和精神造成长期影响。长期饮用咖啡会使身体对咖啡因产生轻度的依赖，因为咖啡因能刺激大脑产生轻度欣快感，并与脑内的腺苷受体结合，让神经元的活动“不衰减”，让人有缓解疲劳的感觉。当每日咖啡因摄入量超过100毫克时，身体可能依赖。若停止摄入咖啡因12～24小时，可能会出现头疼、疲劳、焦虑和注意力无法集中等症状，即“咖啡因戒断”。但这种反应与毒品和精神类药物戒断时产生的持续性反应不同，大多数人可在2～3天内恢复。

哪些人不适合喝咖啡呢？

尽管咖啡能够带来身心愉悦，但并不适合所有人群。对于正处于身体和神经发育重要时期的儿童青少年，以及对咖啡因敏感的人，长期失眠的人，患有胃肠道疾病和骨质疏松的人，不建议喝咖啡。咖啡还可能影响食物中铁的吸收，因此缺铁性贫血患者也应避免饮用。孕妇喝咖啡也需谨慎，建议每日不超过1杯。咖啡也不宜与麻黄碱类感冒药同服，以免出现“过量服药”的症状。

此外，对于经常熬夜和加班情况的人，试图通过喝咖啡“续命”是不现实的。咖啡只能提供短暂的大脑兴奋，一味增加咖啡的量，不仅会导致咖啡因依赖，还可能加剧精神焦虑和失眠。因此，建议从长远角度考虑，给予大脑和身体充分的休息。

作者：张 宇 中国疾病预防控制中心 研究员 硕士研究生导师

审核：付 睿 首都医科大学附属北京世纪坛医院 主任医师

The reason why coffee is so popular is not only because of its unique taste, but also because it can bring a sense of pleasure and refresh the mind. Coffee contains caffeine, tannic acid, fat, protein, carbohydrates, minerals, and trace amounts of lime. It is the interaction of complex components that causes different types of coffee to exhibit varying degrees of sweetness, acidity, richness, and purity in taste.

Caffeine, as the most critical active ingredient in coffee, is also the main source of bitterness. It is a xanthine alkaloid compound that, when consumed in moderation, can stimulate the central nervous system, help people stay alert, and enhance their attention and thinking abilities. The bitterness of coffee also comes from the taste of caffeine. In addition, coffee also contains various mineral components such as potassium, magnesium, zinc, and chromium, which greatly benefit the body's metabolism and various physiological functions.

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

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

In addition, there is a certain correlation between daily coffee consumption and factors such as personal weight and coffee type. People with lighter body weight are advised to reduce their consumption accordingly; If you are drinking Italian espresso with high caffeine content, you should also reduce your consumption appropriately. In addition to coffee, many daily drinks such as cola, tea, milk tea, etc. also contain caffeine, so after drinking these drinks, it is also important to remember to reduce the amount of coffee consumed.

After drinking coffee, the heart rate increases. Is this heart disease?

After drinking coffee, the heart rate increases, which 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, leading to a significant increase in heart rate, enhanced myocardial contractility, vasodilation, and increased blood flow velocity. It also increases respiratory rate and gastrointestinal motility. The degree of these physiological reactions varies from person to person, influenced by an individual's tolerance to coffee and the concentration of coffee consumed. For example, people who frequently drink coffee may not feel anything about it, but those who are intolerant to caffeine may feel palpitations, dizziness, and discomfort. Moreover, the higher the concentration of coffee, the more obvious the symptoms will be. Therefore, when enjoying the refreshing effect of coffee, it is also necessary to pay attention to one's own physical reactions and drink in moderation.

Can drinking too much coffee really trigger heart disease?

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

On the one hand, excessive intake of caffeine can increase the burden on the heart and may trigger cardiovascular disease. This is because high doses of caffeine can significantly increase heart rate and blood pressure, putting pressure on the cardiovascular system and increasing the risk of arrhythmia or irregular heartbeat. The increase in heart rate can lead to an increase in myocardial oxygen consumption, and arrhythmia may also cause insufficient blood supply to the heart, which can increase the risk of developing diseases such as coronary heart disease and myocardial infarction.

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

In addition, excessive coffee consumption may also accelerate atherosclerosis and increase the risk of atherosclerosis.

Does drinking coffee cause osteoporosis?

Drinking coffee is only a risk factor for osteoporosis, not a direct pathogenic factor. Moderate consumption of coffee does not directly lead to osteoporosis. Although 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 intestinal tract will correspondingly increase the absorption rate of calcium to compensate for the loss. Therefore, as long as you maintain a balanced diet and drink coffee in moderation, it will not lead to calcium deficiency.

Is coffee really addictive?

Coffee does have some addictive properties, but its withdrawal symptoms usually do not have long-term effects on the body and mind. Long term consumption of coffee can lead to a mild dependence on caffeine in the body, as caffeine can stimulate the brain to produce mild pleasure and bind to adenosine receptors in the brain, allowing neuronal activity to "not decay" and providing a feeling of relief from fatigue. When the daily intake of caffeine exceeds 100 milligrams, the body may become dependent. If caffeine intake is stopped for 12-24 hours, symptoms such as headache, fatigue, anxiety, and difficulty concentrating may occur, known as "caffeine withdrawal". But this reaction is different from the persistent reactions that occur during withdrawal from drugs and psychotropic drugs, and most people can recover within 2-3 days.

Who is not suitable for drinking coffee?

Although coffee can bring physical and mental pleasure, it is not suitable for all people. For children and adolescents who are in an important period of physical and neurological development, as well as those who are sensitive to caffeine, suffer from long-term insomnia, gastrointestinal diseases, and osteoporosis, it is not recommended to drink coffee. 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 not be taken together with ephedrine cold medicines to avoid symptoms of "overdose".

In addition, it is unrealistic for people who frequently stay up late and work overtime to try to "prolong their lives" by drinking coffee. Coffee can only provide brief brain stimulation, and blindly increasing the amount of coffee can not only lead to caffeine dependence, but may also exacerbate mental anxiety and insomnia. Therefore, it is recommended to consider from a long-term perspective and give the brain and body sufficient rest.

Author: Zhang Yu, Researcher and Master's Supervisor at the Chinese Center for Disease Control and Prevention

Reviewed by: Fu Rui, Chief Physician of Beijing Century Altar Hospital Affiliated to Capital Medical University