The understanding that changes in microbiome composition can influence chronic human diseases and the efficiency of therapies has driven efforts to develop microbiota-centred therapies such as first and next generation probiotics, prebiotics and postbiotics, microbiota editing and faecal microbiota transplantation. Central to microbiome research is understanding how disease impacts microbiome composition and vice versa, yet there is a problematic issue with the term ‘dysbiosis’, which broadly links microbial imbalances to various chronic illnesses without precision or definition. Another significant issue in microbiome discussions is defining ‘healthy individuals’ to ascertain what characterises a healthy microbiome. This involves questioning who represents the healthiest segment of our population—whether it is those free from illnesses, athletes at peak performance, individuals living healthily through regular exercise and good nutrition or even elderly adults or centenarians who have been tested by time and achieved remarkable healthy longevity. This review advocates for delineating ‘what defines a healthy microbiome?’ by considering a broader range of factors related to human health and environmental influences on the microbiota. A healthy microbiome is undoubtedly linked to gut health. Nevertheless, it is very difficult to pinpoint a universally accepted definition of ‘gut health’ due to the complexities of measuring gut functionality besides the microbiota composition. We must take into account individual variabilities, the influence of diet, lifestyle, host and environmental factors. Moreover, the challenge in distinguishing causation from correlation between gut microbiome and overall health is presented. The review also highlights the resource-heavy nature of comprehensive gut health assessments, which hinders their practicality and broad application. Finally, we call for continued research and a nuanced approach to better understand the intricate and evolving concept of gut health, emphasising the need for more precise and inclusive definitions and methodologies in studying the microbiome.

中文翻译：

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什么定义了健康的肠道微生物组？


认识到微生物组组成的变化会影响慢性人类疾病和治疗效率，这推动了开发以微生物群为中心的疗法的努力，例如第一代和下一代益生菌、益生元和后生元、微生物群编辑和粪便微生物群移植。微生物组研究的核心是了解疾病如何影响微生物组组成，反之亦然，但“菌群失调”一词存在一个问题，它将微生物失衡与各种慢性疾病广泛联系起来，但没有精确或定义。微生物组讨论中的另一个重要问题是定义 “健康个体 ”，以确定健康微生物组的特征。这包括询问谁代表了我们人口中最健康的部分——无论是那些没有疾病的人、处于最佳表现的运动员、通过定期锻炼和良好营养健康生活的人，甚至是经过时间考验并实现非凡健康长寿的老年人或百岁老人。本综述通过考虑与人类健康和环境对微生物群影响相关的更广泛的因素，来描述“什么定义了健康的微生物组？健康的微生物组无疑与肠道健康有关。然而，由于除了微生物群组成之外，测量肠道功能的复杂性，因此很难确定“肠道健康”的普遍接受定义。我们必须考虑个体差异、饮食、生活方式、宿主和环境因素的影响。此外，还提出了区分肠道微生物组与整体健康之间的因果关系和相关性的挑战。 该综述还强调了综合肠道健康评估的资源密集型性质，这阻碍了其实用性和广泛应用。最后，我们呼吁继续研究和采取细致入微的方法，以更好地了解肠道健康的复杂性和不断发展的概念，强调在研究微生物组时需要更精确和包容的定义和方法。