儿童营养不良是很多低收入国家的一个主要健康问题，虽然死亡率可以通过治疗性食物干预降低，但在严重急性营养不良情况下却难以实现健康生长的完全恢复。在这项研究中，Jeffrey Gordon及同事识别出一组24种细菌，它们在微生物群落中所占比例决定孟加拉国一组健康儿童在出生后前两年是否会形成一个健康的微生物群落。他们定义了一个可以对个体之间进行比较的“微生物群落相对成熟度指数”和“不同年龄微生物群落Z-值”(microbiota-for-age Z-score)，并利用这些指数证明：严重营养不良与微生物群落显著的相对不成熟有关，这种不成熟只能通过两种被广泛采用的营养干预方法得到部分改善。这项工作表明，可能需要时间更长的食物干预措施和/或肠道微生物的增添来实现儿童营养不良中微生物群落不成熟问题的持久修复和更好的临床结果。
Therapeutic food interventions have reduced mortality in children with severe acute malnutrition (SAM), but incomplete restoration of healthy growth remains a major problem1, 2. The relationships between the type of nutritional intervention, the gut microbiota, and therapeutic responses are unclear. In the current study, bacterial species whose proportional representation define a healthy gut microbiota as it assembles during the first two postnatal years were identified by applying a machine-learning-based approach to 16S ribosomal RNA data sets generated from monthly faecal samples obtained from birth onwards in a cohort of children living in an urban slum of Dhaka, Bangladesh, who exhibited consistently healthy growth. These age-discriminatory bacterial species were incorporated into a model that computes a ‘relative microbiota maturity index’ and ‘microbiota-for-age Z-score’ that compare postnatal assembly (defined here as maturation) of a child’s faecal microbiota relative to healthy children of similar chronologic age. The model was applied to twins and triplets (to test for associations of these indices with genetic and environmental factors, including diarrhoea), children with SAM enrolled in a randomized trial of two food interventions, and children with moderate acute malnutrition. Our results indicate that SAM is associated with significant relative microbiota immaturity that is only partially ameliorated following two widely used nutritional interventions. Immaturity is also evident in less severe forms of malnutrition and correlates with anthropometric measurements. Microbiota maturity indices provide a microbial measure of human postnatal development, a way of classifying malnourished states, and a parameter for judging therapeutic efficacy. More prolonged interventions with existing or new therapeutic foods and/or addition of gut microbes may be needed to achieve enduring repair of gut microbiota immaturity in childhood malnutrition and improve clinical outcomes.