Immigrants to the U.S. might lose touch with certain customs and traditions back home. But here's something else they lose: their microbes. 

移民到美国可能会失去与某些习俗和传统的联系。但这是他们失去的其他东西：他们的微生物。

"When they came to the U.S. almost immediately they began losing their native microbes." Dan Knights, a computational biologist at the University of Minnesota. "And over time the balance shifted to the point where they were dominated by the U.S. associated microbes."

“当他们几乎立即来到美国时，他们开始失去他们的原生微生物。” Dan Knights，明尼苏达大学的计算生物学家。 “随着时间的推移，这种平衡转移到了美国相关微生物占主导地位的地步。”

He's referring to first- and second-generation immigrant women, from the Hmong and Karen ethnic minorities in southeast Asia. His team sequenced the DNA found in their feces.

他指的是来自东南亚的苗族和克伦族少数民族的第一代和第二代移民妇女。他的团队对他们粪便中发现的DNA进行了测序。

And they saw that there was an immediate decline in the number and diversity of gut microbes among the immigrants, compared to their counterparts still living back home. And the decline continued over time.

他们发现移民中肠道微生物的数量和多样性与其仍然居住在那里的同行相比立即下降。随着时间的推移，这种下降趋势

If you're thinking, well, maybe the women just switched up their diets - started eating more hamburgers, more bacon and eggs? Dietary surveys don't bear that out. The women weren't changing their diets nearly fast enough to explain the drop in diversity. 

如果您正在思考，那么，也许女性只是改变了饮食习惯 - 开始吃更多的汉堡包，更多的培根和鸡蛋？饮食调查不能证明这一点。这些女性并没有快速改变饮食习惯来解释多样性的下降。

"It seems as though there's something else going on that has to do with the U.S. lifestyle… Antibiotics could be playing a role. The water supply could be playing a role. Could be other aspects of lifestyle, stress, exercise, hygiene. But we don't have enough information yet to be able to pin it down." 

“好像还有其他事情与美国生活方式有关......抗生素可能起到一定作用。供水可能起到一定作用。可能是生活方式，压力，运动，卫生等其他方面。但我们没有足够的信息可以将其固定下来。“

The results are in the journal Cell. [Pajau Vangay et al, US Immigration Westernizes the Human Gut Microbiome] 

结果发表在Cell杂志上。 [Pajau Vangay等人，US Immigration Westernizes the Human Gut Microbiome]

Some of the missing microbes helped digest traditional foods like tamarind, palm and coconut. But the consequences could be more severe than indigestion. "We have evidence from many studies now, especially even causal evidence in a number of animal studies, that having the wrong set of microbes, or missing the right set of microbes, can cause many of the diseases that are rising in industrialized nations." Things like obesity, metabolic disease. 

一些遗失的微生物帮助消化了罗望子，棕榈和椰子等传统食物。但后果可能比消化不良更严重。 “我们现在从许多研究中得到证据，特别是在许多动物研究中的证据，即拥有错误的微生物，或错过了正确的微生物，可能导致工业化国家中出现的许多疾病。”肥胖，代谢疾病等。

Which we might be able to fix, he says, if we're able to solve this microbial mystery.

他说，如果我们能够解决这个微生物之谜，我们可以解决这个问题。

—Christopher Intagliata 

[The above text is a transcript of this podcast.]