When functioning properly, this ring of tissue plays a crucial role in helping us eat.

當這個組織妥當運作時，它是協助我們進食的關鍵角色。

But when the LES malfunctions, it becomes the main player in heartburn — a searing, sometimes sour-tasting chest-spasm that many people will experience at some point in their lives.

但當 LES 機能失常時，它就成了胃灼熱的主要原因。胃灼熱是一種燒灼且有時會帶有酸味的胸痙攣，許多人在一生中都會經歷到。

We know that humans have been battling heartburn for hundreds, if not thousands of years.

我們知道人類一直在對抗胃灼熱上，若沒有數千年也有數百年之久。

But recently the incidence has risen, making it a common stomach complaint worldwide.

但近期胃灼熱的發生率開始上升，使它成為全球一種常見的胃部不適。

When the symptoms of heartburn become more more regular and intense — such as twice a week week or more — it's diagnosed as Gastroesophageal Reflux Disease, or GERD.

當胃灼熱的症狀變得越來越頻繁且越來越強烈，比如一週兩次，甚至更頻繁時，它會被診斷為胃食道逆流，簡稱 GERD。

But what causes this problem, and how can it be stopped?

但是這個問題是什麼造成的呢？要如何讓它停止呢？

Heartburn starts in an area called the gastroesophageal junction, where the LES resides.

胃灼熱是在一個叫做食道胃接合處的區域開始發生的，也就是 LES 的所在。

This smooth, muscular ring of the LES is moderated by an intricate tree of nerve roots that connect to the brain, the heart, and the lungs.

LES 這一圈平滑的肌肉是由錯綜復雜的樹狀神經所管控， 這些神經與大腦、心臟和肺部相連。

After food enters the stomach from the esophagus, the muscle's task is to stop it from surging back up again.

當食物經由食道進入胃之後，這塊肌肉的工作就是要阻止食物回流到食道。

The LES contracts, squeezing the stomach entrance and creating a high pressure zone that prevents digestive acids from seeping out.

LES 會收縮，擠壓胃部的入口，並製造出一個高壓區， 防止胃酸流出。

But if the LES relaxes at the wrong moment or gradually weakens, it becomes like a faulty, ill-fitting lid, causing the area to depressurize.

但當 LES 在錯誤的時機放鬆，或是逐漸衰弱時，它會變成一個不完善且不吻合的蓋子，造成這塊區域的減壓。

That allows burning stomach acid — and even chunks of food — to spurt into the esophagus, sometimes going as far up as the mouth.

這會促使灼燒的胃酸，甚至食物噴進食道，有時還會衝到嘴巴那麼遠。

The cause of all this internal drama has long been put down to diet.

這些在體內上演的情節一直都被認為與飲食有關。

Foods like caffeine and peppermint contain ingredients that may have a relaxing affect on the LES, which makes it incapable of doing its job.

像是咖啡因和薄荷等食物含有會促使 LES 放鬆的成分， 使它無法好好工作。

Other acidic foods, like citrus and tomatoes, can worsen irritation of the esophagus when they leach out with stomach acid.

其他酸性食物，像是柑橘和番茄，與胃酸一起釋放到食道時，會使食道的刺激更加嚴重。

Carbonated beverages can similarly bubble up in the stomach, forcing open the valve.

汽水也很類似，會在胃部冒泡，促使閥門的開啟。

But researchers have discovered that food isn't the only trigger.

但是研究者發現，食物並不是唯一的起因。

Smoking poses a risk, because the nicotine in cigarettes relaxes the LES.

抽煙會增加風險，因為香菸裡的尼古丁會使 LES 放鬆。

Consuming excessive amounts of alcohol may have a similar effect.

飲酒過量也會有類似的反應。

Pregnant women often experience more heartburn due to the pressure of a growing baby on their stomachs and the levels of certain hormones in their bodies.

孕婦時常會發生胃灼熱，因為正在成長的胎兒會給胃部施加壓力，孕婦體內某種賀爾蒙的量也是一個原因。

Obesity can cause hernias that disrupt the anti-reflux barrier of the gastroesophageal junction that normally protects against heartburn.

肥胖會造成疝氣，這會破壞食道胃接合處 原本用來防止胃灼熱的抗逆流屏障。

Numerous medications, including those for asthma, high blood pressure, birth control, and depression can also have unintended effects on the LES.

許多藥物，包括氣喘、高血壓、避孕和憂鬱症的藥物都可能無意間對 LES 有影響。

An occasional bout of heartburn isn't necessarily something to worry about.

偶發的一次胃灼熱並不是一個需要擔心的事情。

But, if heartburn starts happening regularly, it can weaken the LES muscle over time, letting more and more acid escape.

但是如果胃灼熱開始頻繁的發生，它可能會使 LES 逐漸衰弱，讓更多的胃酸流出。

And if it goes untreated, this can cause bigger problems.

如果沒有治療，它可能會造成更大的問題。

Over time, constant acid leakage from heartburn may form scar tissue which narrows the esophageal tube, making it harder to swallow food.

當胃灼熱的胃酸外漏持續一段時間之後，它會形成疤痕組織，使食道變窄，讓吞嚥食物更加困難。

Ongoing reflux can also damage the cells lining the esophagus — a rare condition called Barrett's esophagus, which can elevate the risk of esophageal cancer.

不斷的逆流也會傷害食道細胞，這是一種罕見疾病，叫做巴瑞特氏食道，它會增加罹患食道癌的風險。

Luckily, heartburn is often treatable with a range of medicines that can help neutralize or reduce stomach acid.

幸運的是胃灼熱通常可以被許多可以中和或是減少胃酸的藥物所治療。

In extreme cases, some people have surgery to tighten the LES to minimize their distress.

有些極端的個案是透過手術讓 LES 變緊以減少其痛苦。

But we can often stop heartburn before it reaches that point.

但是我們通常可以在演變到這種地步之前阻止胃灼熱。

Reducing the consumption of certain foods, not smoking, and maintaining a healthy weight can all dramatically reduce reflux.

減少食用某些食物，不要抽煙和保持健康的體重可以顯著的降低逆流的發生。

With proper care, we can help our LES's keep the chemical fountain of our stomachs in proper order and avoid having to feel the burn.

在妥善的照顧下，我們可以幫助 LES 把我們胃部的化學噴泉給管控好，進而避免經歷這種灼熱感。