Extrinsic factors, such as lifestyle and diet, are shown to be essential in the control of human healthy aging, and thus, longevity. They do so by targeting at least in part the gut microbiome, a collection of commensal microorganisms (microbiota), which colonize the intestinal tract starting after birth, and is established by the age of three. The composition and abundance of individual microbiota appears to continue to change until adulthood, presumably reflecting lifestyle and geographic, racial, and individual differences. Although most of these changes appear to be harmless, a major shift in their composition in the gut (dysbiosis) can trigger harmful local and systemic inflammation. Recent reports indicate that dysbiosis is increased in aging and that the gut microbiota of elderly people is enriched in pro-inflammatory commensals at the expense of beneficial microbes. The clinical consequence of this change remains confusing due to contradictory reports and a high degree of variability of human microbiota and methodologies used. Here, we present the authors’ thoughts that underscore dysbiosis as a primary cause of aging-associated morbidities, and thus, premature death of elderly people. We provide evidence that the dysbiosis triggers a chain of pathological and inflammatory events. Examples include alteration of levels of microbiota-affected metabolites, impaired function and integrity of the gastrointestinal tract, and increased gut leakiness. All of these enhance systemic inflammation, which when associated with aging is termed inflammaging, and result in consequent aging-associated pathologies.

中文翻译：

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肠道菌群是老年人“健康”衰老的关键控制者

外在因素，例如生活方式和饮食习惯，对于控制人类健康的衰老和延年益寿至关重要。他们通过至少部分靶向肠道微生物组（共生微生物（微生物群））来做到这一点，这些微生物从出生后就开始在肠道内定植，并在三岁时建立。各个微生物群的组成和丰度似乎一直在变化，直到成年，大概反映了生活方式以及地理，种族和个体差异。尽管这些变化中的大多数似乎无害，但它们在肠道中的组成发生重大变化（营养不良）会触发有害的局部和全身性炎症。最近的报道表明，病态菌增多随着年龄的增长而增加，老年人的肠道菌群富含促炎功能，却以有益微生物为代价。由于矛盾的报道以及人类微生物群和所使用方法的高度变异性，这种改变的临床结果仍然令人困惑。在这里，我们提出作者的思想，即强调病态发展是衰老相关疾病的主要原因，因此是老年人过早死亡的主要原因。我们提供的证据表明，该病会引发一系列病理和炎症事件。例子包括受微生物群影响的代谢物水平的改变，胃肠道功能和完整性的受损以及肠道渗漏的增加。所有这些都会加剧全身性炎症，