Adjusting Your Body Clock May Stave Off Cancer調生物鐘可防癌

莉迪婭·登沃思/文　張瑤/譯

Research shows that disrupting the bodys circadian rhythm raises cancer risk， and resetting it may bring that risk down.

研究表明，擾亂人體晝夜節律會增加患癌風險，重置生物鐘則可降低風險。

I usually get up by 7 A.M. and am in bed by 10 P.M. I tend to eat meals at the same times of day， too. This may sound a little dull， but its essential for my productivity. Its also a schedule that rarely disrupts my body clock. And a steady clock， it turns out， just might help me and many other people avoid cancer and some other diseases， according to new research.

我通常早上7點之前起床，晚上10點之前睡覺，就連用餐時間也相對固定。這樣的安排或許聽起來有些枯燥，但對保持我的工作效率至關重要。而且，這種作息時間幾乎不會擾亂我的生物鐘。最新研究表明，對于包括我在內的許多人來說，生物鐘穩定或許有助于避免癌癥等疾病。

What I call a body clock really means circadian1 rhythms， from the Latin for “about” and “day.” These are the bodys internal biological pacemakers， physiological fluctuations that help us adjust to the phases of a 24-hour day by synchronizing with environmental cues such as light， dark， temperature and food intake. These rhythms affect sleeping and waking， feeding and fasting， endocrine cycles， immune function， and cell growth.

我所說的生物鐘實際上是指“晝夜節律”。英文circadian源于拉丁語的“大約”和“日”。晝夜節律是人體內部的生物節拍器，通過與光線、暗度、溫度和食物攝入等環境信號同步，產生的生理波動會幫助我們適應一天24小時的不同階段。這些節律會影響到睡眠與清醒、進食與禁食、內分泌周期、免疫功能和細胞生長。

For some time now epidemiological studies of night-shift workers have linked disruptions in circadian rhythms to cancer and other diseases. Much of the evidence concerned breast cancer and to a lesser extent prostate cancer. Duration of shift work made a difference—nurses who worked night shifts for up to 30 years were at moderately increased risk for breast cancer compared with those who did shorter stints2， and those who worked such shifts for more than 30 years had the highest risk. In 2019 the World Health Organization reaffirmed and updated a research statement from the agency showing that shift work is a probable carcinogen3.

一段時間以來，針對夜班工作人員的流行病學調查發現晝夜節律紊亂與癌癥等疾病相關。多數證據指向乳腺癌，其次是前列腺癌。倒班工作年限影響患癌幾率——輪值夜班滿30年的護士罹患乳腺癌的風險略高于夜班工作年限較短的同行，夜班經歷超過30年的護士風險最高。2019年，世界衛生組織再度確認并且更新了該機構的一份研究報告，表明倒班工作可能屬于致癌因素。

Now there is even more evidence involving other types of malignancies， including liver， lung and colorectal cancers， from a spate of4 new studies. “Were starting to understand the reasons these things happen，” says Selma Masri， a circadian biologist at the University of California， Irvine， who has shown how circadian disruption pushes colon cancer progression by interfering with the way certain genes are expressed.

時至今日，大量新研究還提供了涉及其他惡性腫瘤的依據，包括肝癌、肺癌、腸癌等。加州大學歐文分校研究晝夜節律的生物學家塞爾瑪·馬斯里表示：“我們漸漸明白此類事情發生的原因。”此前，她已證明晝夜節律紊亂會干擾某些基因的表達方式，加速結腸癌進展。

The cancer connection comes about through several mechanisms. Circadian disruption affects metabolic pathways， the chemical reactions that produce energy in the body. It tampers with immune function. It also compromises the fidelity of DNA repair in cells. Adult human cells divide every 18 to 24 hours， and one function of the circadian clock is to tell cells to do that at night to avoid DNA damage from sunlight. “When the clock gets disrupted， cells dont know when to divide，” says circadian biologist Satchidananda Panda of the Salk Institute for Biological Studies5. “They can divide faster and become a tumor.”

癌癥發生機制并不單一。晝夜節律紊亂會影響代謝途徑，即為人體供能的一系列化學反應。它還會干擾免疫功能，并且降低細胞中DNA修復的保真度。成年人的細胞每隔18到24小時分裂一次，生物鐘的職責之一就是告訴細胞在夜里分裂，以免陽光照射造成DNA損傷。索爾克生物研究所研究晝夜節律的生物學家薩奇達南達·潘達說：“生物鐘一亂，細胞就不知該何時分裂，分裂速度可能會加快，然后形成腫瘤。”

Circadian disruption doesnt only occur in shift workers. It happens when we consistently dont get a good nights sleep—scientists say this can mean waking up for two or three hours between 10 P.M. and 5 A.M. at least once a week. Wakeful episodes can be caused by jet lag， staying out late， or looking at blue-light-emitting phone screens—which mimic daylight—at night. When and what we eat also cues our rhythms， just as light and dark do， so add snacking at midnight to the list of things to avoid.

晝夜節律紊亂并不僅見于倒班人群。我們普通人若是一直睡眠不足，按照科學家的說法也就是每周不止一次在晚10點到早5點之間清醒兩三個小時，一樣會造成生物鐘紊亂。沒能入睡的原因可能包括時差、晚歸或者夜里看手機——手機屏幕會釋放藍光，光線和日光類似。環境的明暗變化調整晝夜節律，進食時間和攝入的食物也一樣，會對生物鐘產生一定影響，所以半夜吃零食這種事情還是別干為好。

The growing understanding of circadian rhythms also could offer help through whats known as chronotherapy. Certain chemotherapy treatments， for example， are more effective when given in accordance with a patients rhythms. Now researchers are exploring differences in the timing of radiation therapy. Drugs that bolster natural rhythms are also under investigation.

人們對晝夜節律的了解日漸深入，也可能通過所謂的“時間療法”提供幫助。比如，如若配合病人生物鐘進行某些化療，療效或許更好。如今研究人員正在探索不同放療時間對療效的影響，改善節律的藥物也在研發之中。

Shift work is critical and not going away， says Katja Lamia， a circadian biologist at Scripps Research6， but there might be ways of reducing its toll on the body. Her research suggests that subtle increases in body temperature might be an important factor in circadian disruption. If that turns out to be right， Lamia says， “we can use noninvasive monitoring of body temperature in shift workers to evaluate whos at risk and take a personalized scheduling approach.”

斯克里普斯研究所研究晝夜節律的生物學家卡特婭·拉米亞認為，倒班制度極為重要，而且還會一直存在，但我們或許可以想法減少倒班工作對身體的損害。她的研究表明：體溫小幅升高可能是引起晝夜節律紊亂的一個重要因素。拉米亞說，若果真如此，“我們可以對倒班工作人員進行無創體溫監測，評估個體風險，采取個性化的排班方法”。

For those who dont work at night， changing some routines might be enough. A good nights sleep should be a priority. Eating habits can also play a role. Panda and his colleagues are investigating a practice known as time restricted eating （TRE） or intermittent fasting. That might mean delaying breakfast by an hour or two until cortisol levels drop and eating dinner at least three hours before your habitual bedtime. In a 12-week study of firefighters， TRE benefited their metabolic health and improved their sleep. In mice， it has been shown to reduce the risk of cancer or to slow the growth of tumors.

不用上夜班的人也許只需改變一些生活習慣即可，最重要的是夜里睡個好覺。飲食習慣也有一定影響。潘達和同事正在研究“限時進食”，也叫“間歇性禁食”。意思大概是早餐推遲一兩個小時，等到皮質醇水平下降，并且在日常就寢前至少3個小時吃完晚飯。一項對消防員進行的為期12周的研究發現，限時進食有利于其代謝健康并改善其睡眠。小鼠實驗表明，這種方法可以降低患癌風險，減緩腫瘤生長。

Maybe， Panda says， respecting our circadian rhythms can help protect our time-sensitive bodies.

潘達表示，或許尊重晝夜節律能夠幫助我們保護對時間敏感的身體。

（譯者單位：中央民族大學外國語學院）

1 circadian晝夜的。

2 stint工作期限。? 3 carcinogen致癌物質。? 4 spate of sth一連串。

5位于美國加州南部拉霍亞，系美國生命科學領域成果最多、品質最高的研究機構之一。

6美國斯克里普斯研究所，國際知名的綜合性醫學研究及教育機構。