The plant defence compound caffeine is widely consumed as a performance enhancer in a sporting context, with potential benefits expected in both physiological and psychological terms. However, although caffeine modestly but consistently improves alertness and fatigue, its effects on mental performance are largely restricted to improved attention or concentration. It has no consistent effect within other cognitive domains that are important to sporting performance, including working memory, executive function and long-term memory. Although caffeine’s central nervous system effects are often attributed to blockade of the receptors for the inhibitory neuromodulator adenosine, it also inhibits a number of enzymes involved both in neurotransmission and in cellular homeostasis and signal propagation. Furthermore, it modulates the pharmacokinetics of other endogenous and exogenous bioactive molecules, in part via interactions with shared cytochrome P450 enzymes. Caffeine therefore enjoys interactive relationships with a wide range of bioactive medicinal and dietary compounds, potentially broadening, increasing, decreasing, or modulating the time course of their functional effects, or vice versa. This narrative review explores the mechanisms of action and efficacy of caffeine and the potential for combinations of caffeine and other dietary compounds to exert psychological effects in excess of those expected following caffeine alone. The review focusses on, and indeed restricted its untargeted search to, the most commonly consumed sources of caffeine: products derived from caffeine-synthesising plants that give us tea (Camellia sinensis), coffee (Coffea genus), cocoa (Theabroma cacao) and guaraná (Paullinia cupana), plus multi-component energy drinks and shots. This literature suggests relevant benefits to mental performance that exceed those associated with caffeine for multi-ingredient energy drinks/shots and several low-caffeine extracts, including high-flavanol cocoa and guarana. However, there is a general lack of research conducted in such a way as to disentangle the relative contributions of the component parts of these products.

植物防御化合物咖啡因被广泛用作体育运动中的表现增强剂，预计在生理和心理方面都有潜在的好处。然而，尽管咖啡因可以适度但持续地提高警觉性和疲劳度，但它对精神表现的影响很大程度上仅限于提高注意力或注意力。它在对运动表现很重要的其他认知领域（包括工作记忆、执行功能和长期记忆）没有一致的影响。虽然咖啡因对中枢神经系统的影响通常归因于抑制抑制性神经调节剂腺苷的受体，但它也会抑制许多参与神经传递、细胞稳态和信号传播的酶。此外，它部分通过与共享细胞色素 P450 酶的相互作用来调节其他内源性和外源性生物活性分子的药代动力学。因此，咖啡因与多种生物活性药物和膳食化合物具有相互作用的关系，有可能扩大、增加、减少或调节其功能作用的时间进程，反之亦然。这篇叙述性评论探讨了咖啡因的作用机制和功效，以及咖啡因和其他膳食化合物的组合所产生的心理影响超过单独使用咖啡因后预期的影响的潜力。 该审查的重点是，实际上将其无针对性的搜索限制在最常消费的咖啡因来源：来自咖啡因合成植物的产品，这些植物为我们提供茶（ Camellia sinensis ）、咖啡（咖啡属）、可可（ Theabroma cacao ）和瓜拉纳（ Paullinia cupana ），加上多成分能量饮料和饮料。该文献表明，对于心理表现的相关益处超过了多成分能量饮料/饮料和几种低咖啡因提取物（包括高黄烷醇可可和瓜拉那）中咖啡因的相关益处。然而，普遍缺乏以理清这些产品组成部分的相对贡献的方式进行的研究。