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  • There is a curse that has plagued humanity since ancient times.


  • The Greeks fought it by chewing aromatic resins, while the Chinese resorted to egg shells.


  • In the ancient Jewish Talmud, it's even considered legal grounds for divorce.


  • This horrible scourge is halitosis, otherwise known as bad breath.


  • But what causes it, and why is it so universally terrifying?


  • Well, think of some of the worst odors you can imagine, like garbage, feces or rotting meat.


  • All of these smells come from the activity of microorganisms, particularly bacteria, and, as disgusting as it may sound, similar bacteria live in the moisture-rich environment of your mouth.


  • Don't panic.


  • The presence of bacteria in your body is not only normal, it's actually vital for all sorts of things, like digestion and disease prevention.


  • But like all living things, bacteria need to eat.


  • The bacteria in your mouth feed off of mucus, food remnants, and dead tissue cells.


  • In order to absorb nutrients through their cell membranes, they must break down the organic matter into much smaller molecules.


  • For example, they'll break proteins into their component amino acids and then break those down even further into various compounds.


  • Some of the foul-smelling by-products of these reactions, such as hydrogen sulfide and cadaverine, escape into the air and waft their way towards unsuspecting noses.


  • Our sensitivity to these odors and interpretation of them as bad smells maybe an evolutionary mechanism warning us of rotten food and the presence of disease.


  • Smell is one of our most intimate and primal senses, playing a huge role in our attraction to potential mates.


  • In one poll, 59% of men and 70% of women said they wouldn't go on a date with someone who has bad breath, which maybe why Americans alone spend $1 billion a year on various breath products.

    根據調查,59% 的男人和 70% 的女人表示不會跟有口臭的人約會,這可能就是美國人每年花十億美元在各種口腔清潔產品上的原因。

  • Fortunately, most bad breath is easily treated.


  • The worst smelling byproducts come from gram-negative bacteria that live in the spaces between gums and teeth and on the back of the tongue.


  • By brushing and flossing our teeth, using antibacterial mouthwash at bedtime, gently cleaning the back of the tongue with a plastic scraper and even just eating a healthy breakfast, we can remove many of these bacteria and their food sources.


  • In some cases, these measures may not be enough due to dental problems, nasal conditions, or rarer ailments, such as liver disease and uncontrolled diabetes.


  • Behaviors like smoking and excessive alcohol consumption also have a very recognizable odor.


  • Regardless of cause, the bad smell almost always originates in the mouth and not the stomach or elsewhere in the body.


  • But one of the biggest challenges lies in actually determining how our breath smells in the first place, and it's unclear why.


  • It maybe that we're too acclimatized to the smell inside our own mouths to judge it.


  • And methods like cupping your hands over your mouth, or licking and smelling your wrist don't work perfectly either.


  • One study showed that even when people do this, they tend to rate the smell subjectively according to how bad they thought it was going to be.


  • But there's one simple, if socially difficult way of finding out how your breath smells: just take a deep breath and ask a friend.


There is a curse that has plagued humanity since ancient times.


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B2 中高級 中文 美國腔 TED-Ed 口臭 細菌 味道 分解成 氨基酸

【TED-Ed】深受口臭所擾?引發口臭的原因 (What causes bad breath? - Mel Rosenberg)

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    稲葉白兎 發佈於 2020 年 11 月 06 日