本文选自《经济学人》10月17日刊文章。剖腹产在增加新生儿的存活率、降低孕妇死亡率方面功不可没，但剖腹产毕竟不是自然生产过程，正是它的好处给人类带来潜在风险。剖腹产实际是人类干预自然选择的过程，女性盆腔口径决定胎儿的头颅直径不能过大，否则会难产。在剖腹产出现之前，头骨过大的胎儿在生产过程中自然淘汰掉了，这就保证了存活下来的新生儿的头骨尺寸在一定的范围内。但剖腹产的引入则打破了这种自然选择，这给人类未来命运带来隐患。本文讲述的则是剖腹产的另一种风险——剖腹产新生儿缺乏必要的细菌暴露，比如粪便中的细菌暴露，这可能会影响新生儿免疫系统的发育，在之后的人生中出现过敏、糖尿病的风险更高。而最新的研究发现，在喂新生儿的母乳中加入些许母亲的粪便，可以弥补这一缺陷。这虽然有些不可思议，但也许会让剖腹产新生儿更健康。
选文精讲
How to arm Caesarean babies with the gut bacteria they need
Into the mouths of babes and sucklingsCHILDBIRTH IS MESSY. When a baby comes out, a lot else comes out with it. Some of this material is inevitable, such as the amniotic fluid that presages birth and the placentawhich follows it. But a fair bit of faeces is discharged, too.
- discharge: 这里指“排出”的意思，此外该词还有“出院、解雇”的意思
分娩是混乱的。当一个婴儿出生时，很多其他的东西也随之出来，有些东西是不可避免的，比如预示生产的羊水和随后会出来的胎盘，但是一部分粪便也会被排出。From an evolutionary perspective, that seems surprising. Exposing newborns to such bacteria-laden excrement looks risky. Yet no mechanism has arisen to stop it happening. Evidence is mounting, moreover, that far from being harmful, this exposure is actually important for the development of the child’s immune system. Interaction with the multitude of microscopic organisms a baby picks up when it is born helps that system to learn friend from foe. Without it, immune disorders like allergies and type-1 diabetes may follow. Components of the gut flora are also involved in digesting certain foodstuffs containing complex carbohydrates, and an unbalance in the relevant microbial mix is implicated inobesity.
从进化的角度来看，这似乎很让人吃惊。将新生儿暴露在这种充满细菌的粪便中似乎很危险，然而，还没有一种机制能够阻止它的发生。不过越来越多的证据表明，这种暴露在细菌中不仅没有害处，反而对儿童免疫系统的发展非常重要，婴儿出生时与众多微生物的相互作用有助于免疫系统的提升。没有这种接触过程的话，免疫系统就会紊乱，像过敏、1型糖尿病就可能随之而来。肠道菌群的部分菌落也参与消化某些含有复杂碳水化合物的食物，而相关微生物组合的不平衡与肥胖有关。Babies born via Caesarean section (ie, surgical removal directly from the womb) do not get such a biological baptism, and their guts are left bacterially bereft as a consequence. That has left doctors wondering how best to give them what they are missing. In the past, researchers have skirted around the central point by swabbing the faces of newborns with bacteria collected from their mothers’ vaginas. To no avail. Willem de Vos and Sture Andersson of the University of Helsinki, have therefore taken the bull by the horns. In a paper just published in Cell they demonstrate that feeding newborns a dose of their mothers’ gut bacteria, in the form of faeces inoculated into breast milk, seems more fruitful.
- take the bull by the horns: 不畏艰险
通过剖腹产出生的婴儿(即通过外科手术直接从子宫中取出)不会有这样的微生物考验，结果他们的内脏就没有这样的细菌，这就让医生们在想如何用最好的方式弥补这些剖腹产婴儿所缺失的细菌。过去，研究人员用从新生儿母亲的阴道中收集的细菌来擦拭新生儿的脸来解决这个问题，但无济于事。赫尔辛基大学的威廉·德·沃斯和斯图尔·安德森因此不畏挫折，在刚刚发表在《细胞》杂志上的一篇论文中，他们证明给新生儿喂食一定剂量的母体肠道细菌，以粪便的形式注入母乳中，似乎效果更好。
