Adjusting Your Body Clock May Stave Off Cancer调生物钟可防癌

莉迪娅·登沃思/文　张瑶/译

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

研究表明，擾乱人体昼夜节律会增加患癌风险，重置生物钟则可降低风险。

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点之前起床，晚上10点之前睡觉，就连用餐时间也相对固定。这样的安排或许听起来有些枯燥，但对保持我的工作效率至关重要。而且，这种作息时间几乎不会扰乱我的生物钟。最新研究表明，对于包括我在内的许多人来说，生物钟稳定或许有助于避免癌症等疾病。

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.

我所说的生物钟实际上是指“昼夜节律”。英文circadian源于拉丁语的“大约”和“日”。昼夜节律是人体内部的生物节拍器，通过与光线、暗度、温度和食物摄入等环境信号同步，产生的生理波动会帮助我们适应一天24小时的不同阶段。这些节律会影响到睡眠与清醒、进食与禁食、内分泌周期、免疫功能和细胞生长。

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.

一段时间以来，针对夜班工作人员的流行病学调查发现昼夜节律紊乱与癌症等疾病相关。多数证据指向乳腺癌，其次是前列腺癌。倒班工作年限影响患癌几率——轮值夜班满30年的护士罹患乳腺癌的风险略高于夜班工作年限较短的同行，夜班经历超过30年的护士风险最高。2019年，世界卫生组织再度确认并且更新了该机构的一份研究报告，表明倒班工作可能属于致癌因素。

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.

时至今日，大量新研究还提供了涉及其他恶性肿瘤的依据，包括肝癌、肺癌、肠癌等。加州大学欧文分校研究昼夜节律的生物学家塞尔玛·马斯里表示：“我们渐渐明白此类事情发生的原因。”此前，她已证明昼夜节律紊乱会干扰某些基因的表达方式，加速结肠癌进展。

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.”

癌癥发生机制并不单一。昼夜节律紊乱会影响代谢途径，即为人体供能的一系列化学反应。它还会干扰免疫功能，并且降低细胞中DNA修复的保真度。成年人的细胞每隔18到24小时分裂一次，生物钟的职责之一就是告诉细胞在夜里分裂，以免阳光照射造成DNA损伤。索尔克生物研究所研究昼夜节律的生物学家萨奇达南达·潘达说：“生物钟一乱，细胞就不知该何时分裂，分裂速度可能会加快，然后形成肿瘤。”

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.

昼夜节律紊乱并不仅见于倒班人群。我们普通人若是一直睡眠不足，按照科学家的说法也就是每周不止一次在晚10点到早5点之间清醒两三个小时，一样会造成生物钟紊乱。没能入睡的原因可能包括时差、晚归或者夜里看手机——手机屏幕会释放蓝光，光线和日光类似。环境的明暗变化调整昼夜节律，进食时间和摄入的食物也一样，会对生物钟产生一定影响，所以半夜吃零食这种事情还是别干为好。

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.

人们对昼夜节律的了解日渐深入，也可能通过所谓的“时间疗法”提供帮助。比如，如若配合病人生物钟进行某些化疗，疗效或许更好。如今研究人员正在探索不同放疗时间对疗效的影响，改善节律的药物也在研发之中。

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昼夜节律的生物学家卡特娅·拉米亚认为，倒班制度极为重要，而且还会一直存在，但我们或许可以想法减少倒班工作对身体的损害。她的研究表明：体温小幅升高可能是引起昼夜节律紊乱的一个重要因素。拉米亚说，若果真如此，“我们可以对倒班工作人员进行无创体温监测，评估个体风险，采取个性化的排班方法”。

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变一些生活习惯即可，最重要的是夜里睡个好觉。饮食习惯也有一定影响。潘达和同事正在研究“限时进食”，也叫“间歇性禁食”。意思大概是早餐推迟一两个小时，等到皮质醇水平下降，并且在日常就寝前至少3个小时吃完晚饭。一项对消防员进行的为期12周的研究发现，限时进食有利于其代谢健康并改善其睡眠。小鼠实验表明，这种方法可以降低患癌风险，减缓肿瘤生长。

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

潘达表示，或许尊重昼夜节律能够帮助我们保护对时间敏感的身体。

（译者单位：中央民族大学外国语学院）

1 circadian昼夜的。

2 stint工作期限。  3 carcinogen致癌物质。  4 spate of sth一连串。

5位于美国加州南部拉霍亚，系美国生命科学领域成果最多、品质最高的研究机构之一。

6美国斯克里普斯研究所，国际知名的综合性医学研究及教育机构。