Abstract：
Coffee is one of the three most consumed beverages in the world. It is made by first roasting coffee beans, and then grinding and boiling or steeping the roasted beans in water (brewing). The process of roasting and brewing produces a complex mix of bioactive compounds, including methylxanthines (caffeine, theobromine, theophylline), diterpenes, chlorogenic acid, trigonelline, flavonoids, and hydroxycinnamic acid. In the body, these compounds may be metabolized to produce other bioactive compounds. For example, caffeine is primarily (80%) broken down by demethylation to produce paraxanthine. In the post-ingestion period, levels of paraxanthine may be higher than caffeine due to its slower elimination. Hence, while paraxanthine is not found in coffee itself, it has many of the same properties as caffeine and may be a major contributor to its metabolic effects. The impacts of caffeine and paraxanthine on metabolism relate to their impact on adenosine receptors (notably the A2A receptor). It has been known for almost 100 years that intake of coffee stimulates metabolism by between 5% and 20% for at least 3 h. About half of the increase in metabolic rate after drinking coffee is due to caffeine and derivatives, but the source of the other half is unclear. There are large differences in the response to the same amount of coffee in different individuals, which may be related to caffeine clearance rates, effects of other unknown pathways, genetic polymorphism, age, sex, and body composition.
摘要：
咖啡是世界上消耗最多的三种饮料之一。它是通过首先烘烤咖啡豆，然后将烘烤过的咖啡豆研磨并煮沸或在水中浸泡（冲泡）制成的。烘烤和酿造过程产生了复杂的生物活性化合物混合物，其中包括甲基黄嘌呤（咖啡因，可可碱,茶碱)，二萜,绿原酸,三七碱,黄酮类化合物和羟基肉桂酸。在体内,这些化合物可被代谢以产生其它生物活性化合物。例如,咖啡因主要（80％）通过去甲基化分解产生黄嘌呤。在摄入后的时期，由于其消除速度较慢，对黄嘌呤的水平可能高于咖啡因。因此，虽然咖啡本身中没有副黄嘌呤，它具有许多与咖啡因相同的特性，并且可能是其代谢作用的主要原因。咖啡因和对黄嘌呤对代谢的影响与它们对腺苷受体(特别是A2A受体)的影响有关。近100年来，人们已经知道，摄入咖啡会在至少3小时内刺激5％至20％的新陈代谢。大约一半的代谢率增加后喝咖啡是由于咖啡因和衍生物，但另一半的来源不清楚。不同个体对相同量咖啡的反应存在很大差异，这可能与咖啡因清除率有关，其他未知途径的影响，遗传多态性,年龄,性和身体成分。
