(单词翻译:单击)
If you got to spend time with your family back during the holidays, you might have noticed that grandpa smells a little… old.
如果你的假期和家人待在一起,你可能会注意到爷爷笑起来有点...老 。
Not stinky or bad — he just had that distinctive old person smell which some people describe as grassy or greasy.
这样并不恶心也不糟糕—只是那种笑是典型的老年人式微笑,有些人将其描述为油脂过多的微笑 。
And you weren’t imagining it, either.
你也绝对想象不到 。
Like baby humans, older humans do have a certain odor, and it’s likely caused by the chemical nonenal.
就像是人类婴儿、老年人都会带有某种气味,这似乎是由化学壬烯醛所引起的 。
More specifically, that smell is caused by a version of the molecule called 2-nonenal, and it occurs naturally on human skin.
具体来说,这种气味是由被称为2-壬烯醛的分子的一种版本所引起的,通常反应于人类皮肤上 。
Researchers have found that nonenal begins appearing around age 40, and that the amount of it increases as you age.
研究员发现壬烯醛在约40岁时出现,并随着年龄的增长而增加 。
It all has to do with the complex chemistry in your skin.
这一切都与皮肤中复杂的化学物有关 。
See, your skin secrets fats to help form a barrier between your body and everything in the outside world.
你看,皮肤藏着的油脂能够帮助在你身体和外界物质之间形成屏障 。
It helps keep moisture in and bad things out. And these fats are found in the outer layer of your skin — the stratum corneum.
它能帮助锁住水分并排除有害物质 。这些油脂位于你皮肤的外层—角质层 。
Now, when those fats are exposed to oxygen in air, they start to break down and form other chemicals, also known as being oxidized.
现在当那些油脂暴露于空气中的氧气之中,就会开始分解并形成其他化学物质,同样也称为被氧化 。
But your body kind of needs those fats. So to help prevent this, your skin also produces antioxidants.
但你的身体又需要那些油脂 。所以为了预防流失,你的皮肤也同样产生抗氧化剂 。
But as you age, two things happen. One is that your skin produces fewer antioxidants, so more fats get oxidized.
但随着年龄增长,会发生两件事 。第一是你的皮肤产生越来越少的抗氧化剂,因此更多油脂会被氧化 。
And the other is that the types of fats your skin secretes also changes, which might have to do with how your hormones change over time.
另一件事是你皮肤所藏匿的油脂类型同样改变了,这或许和你的激素变化有关 。
And when those new fats get oxidized, that creates nonenal. As you get older, your skin produces more of these specific fats and fewer antioxidants.
当那些新油脂被氧化时,就会产生壬烯醛 。随着年龄增长,你的皮肤产生更多那种特别油脂以及更少的抗氧化剂 。
So you get more nonenal, and more Old People Smell.
所以你会获得更多的壬烯醛以及更多的老年人气味 。
So what can you do about it? Not much. Nonenal isn't water-soluble, which means it won't dissolve in water and it's hard to wash off.
那么我们能做些什么呢?能做的不多 。壬烯醛不是可溶于水的,这就意味着它无法在水中溶解,很难清洗掉 。
Soap can remove non-water soluble substances, but it doesn't remove all the fats from your skin.
肥皂能够洗掉非水溶性物质,但却不能洗掉你皮肤上的所有油脂 。
If it did, your skin would be really dry and uncomfortable. Which means that, even after bathing, some nonenal is still left on your body.
如果洗掉,你的皮肤会变得非常干燥且不适 。这就意味着,即使在洗完澡之后,仍有些壬烯醛会留在你的身体上 。
And while many commercial soaps contain deodorants to combat other bodily odors, most don't yet contain deodorants targeted for nonenal.
虽然许多售卖的肥皂都含有香体剂能够消除身体的体味,但多数肥皂却不含有对抗壬烯醛的香体剂 。
So smelling like it does not indicate poor hygiene.
所以闻起来臭臭的并不代表卫生情况糟糕 。
Whether or not you like the smell probably depends on your personal experiences, your culture, and how you feel about getting older,
你是否喜欢这种气味取决于你的个人经历、文化以及你如何看待衰老,
but by itself, that smell is a totally normal part of aging.
但是就其本身而言,那种气味完全是老年化的正常部分 。
In fact, in a blind sniff test, the body odor of people over age 75 was described as "neutral" and rated as less unpleasant than that of young or middle-aged people.
事实上,在一场盲嗅测试中,75岁以上老年人的体味被描述为“中性味道”并被认为比少年或中年人的味道要好些 。
And in general, you might even consider nonenal as the smell of a survivor, of experience...or of the most interesting people in the world.
通常你或许甚至将这种壬烯醛认为是幸存者、经历或者是世界上最有趣的人的味道 。
Thanks for asking, and thanks to all of our awesome patrons on Patreon who keep these answers coming.
感谢提问,感谢所有Patreon上一直提问的赞助人 。
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如果想要提问,请登录patreon.com/scishow 。