The prevalence of brain disorders, including stress-related neuropsychiatric disorders and conditions with cognitive dysfunction, is rising. Poor dietary habits contribute substantially to this accelerating trend. Conversely, healthy dietary intake supports mood and cognitive performance. Recently, the communication between the microorganisms within the gastrointestinal tract and the brain along the gut–brain axis has gained prominence as a potential tractable target to modulate brain health. The composition and function of the gut microbiota is robustly influenced by dietary factors to alter gut–brain signalling. To reflect this interconnection between diet, gut microbiota and brain functioning, we propose that a diet–microbiota–gut–brain axis exists that underpins health and well-being. In this Review, we provide a comprehensive overview of the interplay between diet and gut microbiota composition and function and the implications for cognition and emotional functioning. Important diet-induced effects on the gut microbiota for the development, prevention and maintenance of neuropsychiatric disorders are described. The diet–microbiota–gut–brain axis represents an uncharted frontier for brain health diagnostics and therapeutics across the lifespan.

脑部疾病（包括与压力相关的神经精神疾病和认知功能障碍）的患病率正在上升。不良的饮食习惯在很大程度上导致了这一加速趋势。相反，健康的饮食摄入可以支持情绪和认知能力。最近，胃肠道内的微生物与大脑之间沿肠-脑轴的通讯作为调节大脑健康的潜在易处理目标而受到重视。肠道微生物群的组成和功能受到饮食因素的强烈影响，从而改变肠-脑信号传导。为了反映饮食、肠道微生物群和大脑功能之间的这种相互联系，我们提出饮食-微生物群-肠-脑轴的存在支撑着健康和福祉。在这篇综述中，我们全面概述了饮食与肠道微生物群组成和功能之间的相互作用以及对认知和情绪功能的影响。描述了饮食对肠道微生物群的重要影响，以促进神经精神疾病的发生、预防和维持。饮食-微生物群-肠-脑轴代表了整个生命周期中大脑健康诊断和治疗的未知前沿。