科学美国人60秒：你是不是又吃多了?

This is Scientific American’s 60-Second Science, I’m Karen Hopkin.

这里是《科学美国人》的60 秒科学，我是凯伦·霍普金。

‘Tis the season…for overeating! But it’s not just your lack of willpower or the omnipresent holiday treats. No, you can lay some of the blame on ghrelin. Because a new study shows that ghrelin, the hormone that makes you hungry, also makes food…and food smells…irresistibly appealing. The finding appears in the journal Cell Reports. [Jung Eun Han et al, Ghrelin Enhances Food Odor Conditioning in Healthy Humans: An fMRI Study]

这是暴饮暴食的季节!但这并不仅仅是因为你缺乏意志力或无处不在的节日大餐。不，你可以把部分责任归咎于饥饿激素。因为一项新的研究表明，让你感到饥饿的激素——胃饥饿素，也会让食物……而且食物的气味……难以抗拒地诱人。这项发现发表在《细胞》杂志上。

Ghrelin is produced in the stomach, and its levels rise before your habitual mealtimes and after you haven’t eaten for an extended period. So the hormone reminds you to put something in your belly. Injecting rats with ghrelin encourages them to eat…and people who receive a dose of ghrelin grab extra helpings from the buffet.

胃促生长素是在胃里产生的，它的水平在你平时吃饭之前和你长时间没吃东西之后会上升。所以荷尔蒙会提醒你在肚子里放点东西。给老鼠注射胃促生长素会鼓励它们进食……而那些吃了胃促生长素的人则会从自助餐中多拿一份。

But how does the hormone induce overindulgence? To find out, researchers at McGill University trained volunteers to associate random images with the smell of food. For example, every time they saw a tree, they might get a whiff of freshly baked bread. At the same time, some of the subjects received ghrelin; others got only saline.

但是荷尔蒙是如何诱导过度放纵的呢?为了找到答案，麦吉尔大学(McGill University)的研究人员训练志愿者将随机图像与食物的气味联系起来。例如，每当他们看到一棵树，他们可能会闻到新鲜烤面包的味道。同时，部分受试者接受饥饿素治疗;另外一些人只喝了生理盐水。

The volunteers were then ushered into an fMRI machine, where the researchers watched their brains to see which parts got turned on by different images.Seems that in subjects under the influence of ghrelin, the brain region involved in pleasure and reward lit up only when volunteers viewed the images they associated with food aromas. Their brain pleasure centers were disinterested in images that had not been paired with food smells.

然后，志愿者们被引导进入fMRI机器，研究人员观察他们的大脑，看哪些部位被不同的图像激活。似乎在饥饿激素的影响下，只有当志愿者看到与食物香味有关的图像时，大脑中与愉悦和奖励有关的区域才会被激活。他们的大脑愉悦中心对没有与食物气味配对的图像不感兴趣。

Also, when participants were then asked to rate the pleasantness of the images, the ones who’d been exposed to ghrelin gave higher grades to the food-associated pictures than did folks who got no ghrelin. So when visions of sugarplums…or the smell of apple pie…get your stomach growlin’…you can thank—or blame—your ghrelin. As you reach for a fork.

同时，当参与者被要求评价图片的愉悦度时，那些接触饥饿素的人比那些没有接触饥饿素的人对食物相关的图片给出了更高的评分。所以，当你看到甜李子……或者苹果派的味道……让你的胃咕咕叫……你可以感谢——或者责备——你的胃饥饿素。当你伸手拿叉子的时候。

Thanks for listening for Scientific American’s 60-Second Science, I’m Karen Hopkin.

感谢收听《科学美国人》的60 秒科学，凯伦·霍普金报道。