Simple Sugars Wipe Out Beneficial Gut Bugs

　　单糖会破坏肠道益生菌

　　We all know that stuffing our faces with sweet treats is not good for us.

　　我们都知道，吃太多的甜食对我们的身体没有好处。

　　In part because it's bad for the health-promoting bacteria that inhabit our intestines. Now, researchers have figured out how simple sugars wipe out a particular strain of beneficial gut microbes.

　　部分原因是甜食会破坏我们肠道内对健康有益的细菌。如今，研究人员发现了单糖是如何对一种特殊的肠道益生菌造成破坏的。

　　"The underlying assumption that existed in the literature was that simple sugars such as fructose and sucrose which are prevalent in Western diet are not good for humans." Yale professor of Microbial Pathogenesis Eduardo Groisman, who led the study.

　　主导这项研究的耶鲁大学微生物病原学教授爱德华多·格罗伊斯曼说：“文献中的基本假设是，西方饮食中普遍存在的果糖和蔗糖不利于人体健康。”

　　Simple sugars—like those in high fructose corn syrup or the table sugar formally known as sucrose—were thought to be absorbed in the small intestine, so a lot of our gut bacteria would never actually be exposed to them.

　　此前人们认为，诸如高果糖玉米糖浆或食糖（正式名称为蔗糖）中的单糖是在小肠中被吸收的，因此许多肠道细菌是接触不到单糖的。

　　Because fiber and complex carbs, made of long chains of sugar molecules, are harder to digest, they make it all the way to the large intestine, where they promote the growth of good bugs like Bacteroides thetaiotaomicron—a microbe found in individuals who are healthy and lean.

　　由于纤维和由长链糖分子构成的复合碳水化合物很难被消化，所以它们会一路来到大肠，促进大肠中的多形拟杆菌（一种在健康、苗条者体内发现的微生物）等益生菌的生长。

　　"But now what our work actually shows is that both fructose and sucrose do make it to the colon where the microbiota exist. And second that these sugars impact a good bacterium even though nutrition is not involved."

　　“但现在我们的研究实际上表明，果糖和蔗糖确实能到达有微生物群存在的结肠。虽然这些单糖并不为它们提供营养，但还是会对益生菌产生影响。”

　　In other words, the bacteria are not using fructose and sucrose as food. Instead, the sugars serve as signals that shut down production of a protein that beneficial Bacteroides need to colonize the intestine.

　　换句话说，这些细菌不会将果糖和蔗糖作为食物。相反，单糖作为一种信号抑制了有益的拟杆菌在肠道内定植所需蛋白质的产生。

　　The findings appear in the Proceedings of the National Academy of Sciences. Groisman says he'd like to explore whether complex polysaccharides can save Bacteroides from this sugary death sentence. Because then maybe we can eat cake and have our gut bugs too.

　　这项研究结果发表于《美国国家科学院院刊》上。格罗伊斯曼表示，他想探究复合多糖能否使拟杆菌免于这种“甜蜜的死刑判决”。因为这样也许我们就既能吃蛋糕，又能保护我们的肠道益生菌。

　　(全文共286个词)

　　重难点词汇：

　　intestine  n. 肠；肠道 adj. 内部的；国内的

　　prevalent  adj. 流行的；普遍的，广传的

　　absorb  vt. 吸收；吸引；承受；理解；使…全神贯注