Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA 01760, USA.
Mil Med. 2021 Feb 26;186(3-4):e310-e318. doi: 10.1093/milmed/usaa261.
Respiratory tract infections (RTI), such as those caused by influenza viruses and, more recently, the severe acute respiratory syndrome coronavirus-2, pose a significant burden to military health care systems and force readiness. The gut microbiota influences immune function, is malleable, and may provide a target for interventions aiming to reduce RTI burden. This narrative review summarizes existing evidence regarding the effectiveness of probiotics, prebiotics, and synbiotics, all of which are gut microbiota-targeted interventions, for reducing the burden of RTI in military-relevant populations (i.e., healthy non-elderly adults).
A systematic search strategy was used to identify recent meta-analyses and systematic reviews of randomized controlled trials conducted in healthy non-elderly adults which examined effects of probiotics, prebiotics, or synbiotics on the incidence, duration, and/or severity of RTI, or on immune responses to vaccinations against viruses that cause RTI. Relevant randomized controlled clinical trials not included in those reports were also identified.
Meta-analyses and multiple randomized controlled trials have demonstrated that certain probiotic strains may reduce the incidence, duration, and/or severity of RTI and improve immune responses to vaccination against RTI-causing pathogens in various populations including healthy non-elderly adults. Fewer randomized controlled trials have examined the effects of prebiotics or synbiotics on RTI-related outcomes in healthy non-elderly adults. Nevertheless, some studies conducted within that population and other populations have observed that certain prebiotics and synbiotics reduce the incidence, duration, and/or severity of RTI or improve immune responses to vaccinations against RTI-causing viruses. However, across all product classes, not all product formulations have shown benefit, and most have not been tested in multiple randomized controlled trials in military-relevant populations.
Dietary supplementation with certain gut microbiota-targeted interventions, and certain probiotics in particular, may provide viable strategies for reducing RTI-related illness in military personnel. Research in military populations is warranted to fully understand the magnitude of any military health and cost benefits, and to establish definitive recommendations for use.
呼吸道感染（RTI），如流感病毒引起的感染，以及最近的严重急性呼吸综合征冠状病毒 2 型引起的感染，给军队的医疗保健系统和战备能力带来了重大负担。肠道微生物群会影响免疫功能，具有可变性，并且可能成为旨在减轻 RTI 负担的干预措施的目标。本综述总结了现有关于益生菌、益生元和合生元（均为肠道微生物群靶向干预措施）在减少与军事相关人群（即健康非老年人）RTI 负担方面的有效性的证据。
使用系统搜索策略来确定最近的荟萃分析和系统评价，这些分析和评价针对健康非老年人进行了随机对照试验，研究了益生菌、益生元或合生元对 RTI 的发生率、持续时间和/或严重程度，或对针对引起 RTI 的病毒的疫苗接种的免疫反应的影响。还确定了未包含在这些报告中的相关随机对照临床试验。
荟萃分析和多项随机对照试验表明，某些益生菌菌株可能降低 RTI 的发生率、持续时间和/或严重程度，并改善针对 RTI 病原体的疫苗接种的免疫反应，包括健康的非老年人。较少的随机对照试验研究了益生元和合生元对健康非老年人 RTI 相关结局的影响。尽管如此，在该人群和其他人群中进行的一些研究观察到，某些益生元和合生元可降低 RTI 的发生率、持续时间和/或严重程度，或改善针对 RTI 病毒的疫苗接种的免疫反应。然而，在所有产品类别中，并非所有产品配方都显示出益处，并且大多数产品尚未在与军事相关的人群中进行多次随机对照试验测试。
通过饮食补充某些肠道微生物群靶向干预措施，特别是某些益生菌，可能为减少军事人员 RTI 相关疾病提供可行的策略。需要在军事人群中进行研究，以充分了解任何军事健康和成本效益的程度，并为其使用建立明确的建议。
