关于咖啡的四问四答Four Questions and Four Answers about Coffee
□厦门大学附属第一医院临床营养科副主任医师 刘少杰
清晨提神、午后“续航”，咖啡已经成为不少职业人群的日常饮品。不过，同样叫咖啡，有的只是浓缩咖啡加水，有的却加入了大量的牛奶、糖浆和奶油；有人喝完精神抖擞，也有人喝完出现心慌、手抖和失眠等症状。咖啡究竟是健康饮品还是身体负担？答案并不是简单的能喝或不能喝，关键在于喝什么、喝多少、什么时候喝，以及是否适合自己。
问：适量饮用咖啡，对身体有哪些益处？
答：
咖啡还含有绿原酸等多酚类物质。研究发现，习惯性饮用咖啡与较低的全因死亡及2型糖尿病、部分肝病、帕金森病发生风险相关。但需要强调的是，“相关”不等于“因果”。咖啡不是药，也不意味着原本不喝咖啡的人必须为了健康开始喝。均衡饮食、规律运动、充足睡眠和不吸烟，仍然是维护健康的基础。
问：意式、美式、拿铁、摩卡、卡布奇诺有何区别？
答：
美式咖啡是在意式浓缩中加水。如果浓缩份数相同，加水只会让味道变淡，并不会减少咖啡因。因此，点单时应关注加了几份浓缩，而不能只看杯子大小。
拿铁由浓缩咖啡和较多牛奶组成，可以提供一定的蛋白质和钙，但选用全脂奶、大杯型或额外添加糖浆后，能量也会随之增加。
卡布奇诺同样含有浓缩咖啡、牛奶和奶泡，牛奶通常少于拿铁，咖啡味更突出。在不额外加糖的情况下，其能量一般低于同杯量拿铁。
摩卡可以理解为加入巧克力酱的拿铁，有时还会添加奶油，通常是这些咖啡中糖含量和能量较高的一种。
想控制体重、血糖或血脂的人群，可以优先选择不加糖的意式、美式，或者不加糖的小杯拿铁、卡布奇诺，尽量少加白砂糖、糖浆、炼乳、奶油和植脂末。
问：怎么喝咖啡更有利于健康？
答：
空腹喝咖啡并非一定伤胃，但如果出现反酸、胃痛、恶心或心慌，就应改在餐后饮用、减少剂量或选择低咖啡因咖啡。低咖啡因咖啡也不是完全不含咖啡因，敏感人群仍需留意。
没有适合所有人的咖啡最佳饮用时刻。多数人安排在早餐后至午后饮用咖啡较为合适。咖啡因的代谢速度存在明显个体差异。研究发现，即使在睡前6小时摄入较高剂量的咖啡因，也可能缩短睡眠时间。因此，一般建议睡前至少6小时停止摄入咖啡因；容易失眠或对咖啡因敏感的人，可以把截止时间提前到中午。若晚上睡不好，第二天再靠咖啡强撑，很容易形成“睡眠不足—喝咖啡—睡眠更差”的恶性循环。
适量咖啡通常不会让习惯饮用者明显脱水，但不能完全代替白开水。长期大量饮用后突然停掉，还可能出现头痛、乏力、注意力下降等短暂的停饮反应，逐渐减量通常比突然停止更容易耐受。
问：哪些人饮用咖啡要慎重？
答：
儿童和青少年不建议把咖啡、奶茶或能量饮料作为日常提神的手段。
容易失眠、焦虑、心悸、胃食管反流，或者血压控制不佳的人，尽量减少咖啡的摄入量。饮用后若出现持续心悸、胸闷、明显头晕等症状，应停止饮用并及时就医。
正在服药者若不确定是否与咖啡存在相互作用，可以先咨询医生或药师。
此外，缺铁性贫血、以植物性食物为主或正在服用铁剂的人，喝咖啡最好与正餐或铁剂间隔1～2小时，以减少对非血红素铁吸收的影响。
血脂偏高且经常饮用法压壶、土耳其咖啡等未经过滤咖啡的人，可以考虑改用纸滤咖啡，以减少可能升高低密度脂蛋白胆固醇的咖啡醇等物质的摄入量。
Liu Shaojie, Deputy Chief Physician of Clinical Nutrition Department, First Affiliated Hospital of Xiamen University
Coffee has become a daily drink for many professionals, as it helps to stay alert in the morning and provides energy in the afternoon. However, also known as coffee, some are just concentrated coffee with water, while others contain large amounts of milk, syrup, and cream; Some people feel refreshed after drinking, while others experience symptoms such as palpitations, hand tremors, and insomnia. Is coffee a healthy beverage or a burden on the body? The answer is not simply whether one can drink or not, the key lies in what to drink, how much to drink, when to drink, and whether it is suitable for oneself.
Q: What are the benefits of moderate coffee consumption for the body?
Answer: Caffeine can temporarily block adenosine receptors in the brain, reducing drowsiness. Therefore, moderate consumption can improve alertness, attention, and reaction speed, and also help some people's exercise endurance. But this effect only temporarily reduces drowsiness and cannot eliminate fatigue and cognitive decline caused by sleep deprivation. After staying up late and drinking coffee, people become more alert, but their judgment and ability to handle complex tasks may not be fully restored. Therefore, it is not recommended to use coffee as a "cure" for staying up late, let alone driving long distances, engaging in strenuous exercise, or engaging in high-risk activities after drinking it.
Coffee also contains polyphenolic substances such as chlorogenic acid. The study found that habitual coffee drinking was associated with a lower risk of all-cause death and type 2 diabetes, some liver diseases and Parkinson's disease. But it should be emphasized that 'correlation' does not equal 'causality'. Coffee is not medicine, nor does it mean that people who originally didn't drink coffee must start drinking it for the sake of their health. A balanced diet, regular exercise, adequate sleep, and non smoking are still the foundation for maintaining health.
Q: What is the difference between Italian, American, latte, mocha, and cappuccino?
Answer: Italian, also known as Italian espresso, is the "base" of most fancy coffees. An Italian espresso is about 30 milliliters, with a small amount and a strong flavor. It usually contains 60-75 milligrams of caffeine, and the specific content may vary depending on the type of coffee beans, powder amount, and extraction method.
American coffee is made by adding water to Italian espresso. If the concentration is the same, adding water will only dilute the taste and not reduce caffeine. Therefore, when placing an order, attention should be paid to how many concentrated portions have been added, rather than just looking at the size of the cup.
Latte is composed of espresso and a lot of milk, which can provide a certain amount of protein and calcium, but choosing whole milk, large cup or adding extra syrup will also increase energy.
Cappuccino also contains espresso, milk, and milk froth, with milk usually being less than latte and the coffee flavor being more prominent. Without additional sugar, its energy is generally lower than that of a latte of the same amount.
Mocha can be understood as a latte with chocolate sauce added, sometimes with cream, usually the one with higher sugar and energy content in these coffees.
People who want to control their weight, blood sugar, or blood lipids can prioritize choosing unsweetened Italian or American, or unsweetened small cup latte or cappuccino, and try to minimize the use of white sugar, syrup, condensed milk, cream, and vegetable powder.
Q: How is drinking coffee more beneficial to health?
Answer: For most healthy adults, the daily caffeine intake should generally not exceed 400 milligrams, and it is best not to exceed 200 milligrams per dose. This calculation includes all sources, including coffee, tea, cola, energy drinks, chocolate, and some medications. The caffeine content varies greatly among different stores, bean varieties, and cup types, so the statement 'how many cups of coffee to drink per day' is not accurate. When purchasing coffee, you can check the product label or inquire about the number of concentrated portions in a cup of coffee.
Drinking coffee on an empty stomach does not necessarily harm the stomach, but if you experience acid reflux, stomach pain, nausea, or palpitations, you should switch to drinking after meals, reduce the dosage, or choose low caffeine coffee. Low caffeine coffee is not completely caffeine free, and sensitive individuals still need to pay attention.
There is no perfect time to drink coffee for everyone. Most people prefer to drink coffee after breakfast until the afternoon. There are significant individual differences in the metabolic rate of caffeine. Research has found that even consuming higher doses of caffeine 6 hours before bedtime may shorten sleep time. Therefore, it is generally recommended to stop consuming caffeine at least 6 hours before bedtime; People who are prone to insomnia or sensitive to caffeine can advance the deadline to noon. If you can't sleep well at night and rely on coffee to support yourself the next day, it is easy to form a vicious cycle of "lack of sleep - drinking coffee - worse sleep".
Moderate coffee usually does not significantly dehydrate habitual drinkers, but it cannot completely replace plain water. After long-term heavy consumption, sudden cessation may also result in short-term cessation reactions such as headache, fatigue, and decreased attention. Gradually reducing the intake is usually easier to tolerate than sudden cessation.
Q: Who should be cautious when drinking coffee?
Answer: The total amount of caffeine in pregnant and preconception women should be controlled within 200 milligrams per day, as caffeine can enter breast milk. Therefore, lactating women should try to drink less or avoid coffee as much as possible, otherwise the baby may experience irritability or sleep changes.
It is not recommended for children and adolescents to use coffee, milk tea, or energy drinks as a daily way to refresh themselves.
People who are prone to insomnia, anxiety, palpitations, gastroesophageal reflux, or poor blood pressure control should try to reduce their intake of coffee. If there are persistent symptoms such as palpitations, chest tightness, and obvious dizziness after drinking, stop drinking and seek medical attention promptly.
If a person taking medication is unsure whether there is an interaction with coffee, they can consult a doctor or pharmacist first.
In addition, for people with iron deficiency anemia, who mainly consume plant-based foods, or are taking iron supplements, it is best to drink coffee 1-2 hours after meals or iron supplements to reduce the impact on non heme iron absorption.
Those who have high blood fat and often drink unfiltered coffee such as French coffee press and Türkiye coffee can consider using paper filter coffee to reduce the intake of caffeinated alcohol and other substances that may increase LDL cholesterol.
(Compiled by Chen Jing)
（陈静 整理）