科学美国人60秒:Fat Gets Gut Bacteria Working against the Waistline

Think it’s your inability to resist cheesecake that’s making it tough to fit into your skinny jeans? Well, your bacteria may share some of the blame. Because a new study in mice shows that the response of intestinal microbes to a high-fat diet ends up triggering the release of a hormone that makes mammals feel hungry, causing them to eat even more. The finding is served up in the journal Nature. [Rachel J. Perry et al., Acetate mediates a microbiome–brain–β-cell axis to promote metabolic syndrome]
设想一下，由于你无法抗拒奶酪蛋糕的诱惑致使你很难穿上你的紧身牛仔裤，那么，你体内的细菌可能要承担部分责任了。一项新的小鼠研究实验表明肠道微生物对高脂饮食的反应会最终引发荷尔蒙的释放，这会使哺乳动物感到饥饿，从而导致吃的更多。该项发现由《自然》杂志所提供。

Previous work has shown that the types of bacteria in the gut in diabetic or obese individuals are different from the bacteria in healthy people. But does this bacterial make up contribute to these disorders? Or is it just a side effect?
先前的研究已经表明在糖尿病患者或肥胖群体的肠道中其细菌类型不同于健康人。但是这些细菌是否会导致患上这些疾病呢？还是只是一种副作用呢？

To unravel this mystery, researchers put mice on a high-fat diet. The animals experienced a build-up of a chemical called acetate, particularly in the large intestine.
为了解开这个谜团，研究人员让小鼠高脂饮食。这些动物经历了一种化学物质的积累过程，称为醋酸。尤其在大肠中。

That location points to gut bacteria, which can produce acetate, as a possible culprit. So the researchers wiped out the microbes using antibiotics or a simple saline wash. And acetate levels plummeted.
该位置指向肠道细菌，它能产生醋酸，是一个潜在的罪魁祸首。因此，研究人员使用抗生素或简单的生理盐水冲洗来消灭微生物并且使醋酸眼浓度下降。

Okay, so the gut bacteria in fat-fed mice make acetate. What does acetate do? Well, it gets the involuntary part of the nervous system, the parasympathetic nervous system, to put out the call to produce more insulin. Unfortunately, in this case, acetate also gets the parasympathetic nervous system to stimulate production of a hunger hormone called ghrelin.  And the more fats an animal consumes, the more acetate it makes—which means the more ghrelin it produces and, of course, the more it eats. And bacteria make the whole sequence happen.
因此，高脂饮食小鼠其肠道细菌可以产生醋酸。醋酸的作用是什么呢？它可以抓住神经系统、副交感神经系统中的无意识部分向其发出信号，产生更多的胰岛素。不幸的是，在这种情况下，醋酸也会促使副交感神经系统刺激产生饥饿激素，称之为胃饥饿素。并且脂肪消耗的越多，体内产生的醋酸就越多。这意味着如果它体内产生更多的生长激素，理所当然，它吃的越多。并且细菌使得整个序列发生。

The researchers are now investigating whether the same biochemical events happen in humans. If they do, it’s possible that obtaining a better assortments of gut bacteria could help us control our weight. Of course, the best way to get those good bacteria is from a fecal transplant—in which bacteria-rich feces come out of one person and into you. The very thought of which could help curb your appetite.
研究人员正在研究是否相同的生化反应会在人类身上发生。假如人类也会这样，那么对肠道细菌更好的分类可以帮助我们控制体重。当然，摄取这些有益细菌的最佳方式是通过粪便移植——出自某一人的装载大量细菌的排泄物将进入到你的体内，想到这儿，可能有助于抑制你的食欲。

—Karen Hopkin
霍普金报道。