Early-onset colorectal cancer incidence among the young, defined as those under age 50, has been rising globally since the early 1990s. Rates for colon and rectal cancers are expected to increase by 90 percent and 124 percent, respectively, by 2030.

从20世纪90年代初开始，早发型大肠癌在年轻人（指50岁以下的人群）中的比率在世界各地都有所增加。到2030年，结肠癌和直肠癌的发生率预计会增加90%和124%。

Early-onset：早发型

One suspected reason behind this trend is increased global consumption of a Westernized diet that consists heavily of red and processed meats, added sugar, and refined grains. Sixty percent of the Standard American Diet, also known as "SAD," is made up of ultra-processed food such as industrial baked sweets, soft drinks, and processed meat. SAD is associated with an increased risk of colorectal cancer.

导致这一上升趋势的一个疑似原因是全球对西式饮食的摄入不断增加。西式饮食包括大量红肉和加工肉类、添加糖以及精制谷物。60%的美国标准饮食，也成为SAD，由过度加工的食品，比如工业烘焙的甜品、软饮料和加工肉类组成。SAD与大肠癌风险增加有关。

One aspect of ultra-processed foods I'm concerned about is how colorful they are. This characteristic is on full display in many delicious foods and treats present during the year-end holidays.

我对过度加工食物比较担心的一点是它们的颜色非常多样。这一特点在许多美味的食物和年末节日中的零食中有充分展现。

However, many of the colors that make up candy canes, sugar cookies, and even cranberry sauce and roast ham, are synthetic. And there's some evidence that these artificial food dyes may trigger cancer-causing processes in the body.

然而，拐杖糖、糖饼干，甚至是蔓越莓酱和烤火腿的许多颜色也是人造的。有一些证据证明，这些人工食用色素也许会触发身体产生致癌反应。

As the director of the Center for Colon Cancer Research at the University of South Carolina, I have been studying the effects of these synthetic food dyes on colorectal cancer development.

作为南卡罗莱纳大学结肠癌研究中心的主任，我一直都在研究这些人工食用色素对大肠癌病程发展的作用。

While research on the potential cancer risk of synthetic food dyes is only just starting, I believe that you may want to think twice before you reach for that colorful treat this holiday season.

尽管关于人工食用色素潜在致癌风险的研究才刚刚开始，我相信在这个节日期间，在拿起色彩鲜艳的零食之前，你可能会三思而后行。

What are synthetic food dyes?

什么是人工食用色素？

The food industry uses synthetic dyes because they make food look better. The first food dyes were created from coal tar in the late 1800s. Today, they are often synthesized from a chemical derived from petroleum called naphthalene to make a final product called an azo dye.

食用行业食用人工食用色素的原因是它们会让食物看上去更诱人。第一批食用色素来自于19世纪的煤焦油。如今，这些色素通常从一种化学物质中合成。这种化学物质提取自被称为萘的石油。从化学物质中合成后，色素就会成为被称为偶氮染料的成品。

coal tar：煤焦油

azo dye：偶氮染料

Food manufacturers prefer synthetic dyes over natural dyes like beet extract because they are cheaper, brighter, and last longer. While manufacturers have developed hundreds of synthetic food dyes over the past century, the majority of them are toxic. Only nine are approved for use in food under U.S. Food and Drug Administration policy, and even fewer pass European Unionregulations.

相较天然色素，比如甜菜提取物，食品制造商更青睐人工色素，这是因为人工色素价格更低、色彩更鲜亮以及更加持久。尽管食品制造商在过去的1个世纪中开发出数百种人工食用色素，但是绝大多数色素都是有毒的。仅有9种食用人工色素获得了美国FDA的使用许可，而通过欧盟法规的则更是少上加少。

What drives colorectal cancer?

是什么导致了大肠癌？

DNA damage is the primary driver of colorectal cancer. When DNA damage occurs on cancer driver genes, it can result in a mutation that tells the cell to divide uncontrollably and turn cancerous.

DNA受损是大肠癌的主要原因。当癌症诱发基因中的DNA受损后，其会导致突变并会命令细胞出现不受控制的分离并具有癌症特性。

Another driver of colorectal cancer is inflammation. Inflammation occurs when the immune system sends out inflammatory cells to begin healing an injury or capture disease-causing pathogens.

When this inflammation persists over time, it can harm otherwise healthy cells by releasing molecules called free radicals that can damage DNA.

另一个导致大肠癌的因素是炎症。当免疫系统送出炎症细胞并开始治愈伤口或捕获致病病原体时，就会出现炎症。当炎症持续不退时，其会通过释放一种被称为自由基的分子（会伤害DNA）而伤害到其他健康的细胞。

Another type of molecule called cytokines can prolong inflammation and drive increased cell division and cancer development in the gut when there isn't an injury to heal.

Long-term poor dietary habits can lead to a simmering low-grade inflammation that doesn't produce noticeable symptoms, even while inflammatory molecules continue to damage otherwise healthy cells.

另一种被称为细胞激素的分子会在肠道没有任何伤口的情况下延缓炎症，促使更多细胞分裂并导致癌细胞生长。

长期不良饮食习惯会导致慢性低度炎症，这种炎症不会产生明显症状，甚至是在炎症分子继续破坏其他健康细胞时亦如此。

Synthetic food dyes and cancer

人工食用色素和癌症

Although none of the FDA-approved synthetic food colors are classified as carcinogens, currently available research points to potential health risks I and others find concerning.

尽管FDA 所批准的人工食用色素都没有被列为致癌物，但是目前现有的研究则证明了我和其他人所关注的，食用色素所具有的潜在健康危害。

For example, the bacteria in your gut can break down synthetic dyes into molecules that are known to cause cancer. More research is needed on how the microbiome interacts with synthetic food coloring and potential cancer risk.

比如，肠道内的细菌可以将人工色素分解为可以引起癌症的分子。关于微生物如何与人工食用色素相互作用以及潜在的癌症风险则需要更多的研究。

Studies have shown that artificial food dyes can bind to the DNA and proteins inside cells. There is also some evidence that synthetic dyes can stimulate the body's inflammatory machinery. Both of these mechanisms may pose a problem for colon and rectal health.

研究表明，人工食用色素可以粘附在DNA和细胞内的蛋白质上。也有一些证据表明，人工色素可以刺激身体的炎症机制。两种机制都会对直肠和结肠的健康造成影响。

Synthetic food dyes have been found to damage DNA in rodents. This is supported by unpublished data from my research team showing that Allura Red, or Red 40, and Tartrazine, or Yellow 5, can cause DNA damage in colon cancer cells with increased dosages and length of exposure in vitro in a controlled lab environment.

人工食用色素可以破坏结肠中的DNA。这一结论有来自我的研究团队的数据支持。这些尚未发表的数据表明，在对照实验环境下，体外剂量和暴露时间增加时，诱惑红或Red40和柠檬黄或Yellow5会引起直肠癌细胞中的DNA受损。

Allura Red：诱惑红

Tartrazine：柠檬黄

Our results will need to be replicated in animal and human models before we can say that these dyes directly caused DNA damage, however.

然而，在得出这些色素会直接引起DNA受损这一结论前，我们的结果还需要在动物和人体模型中平行测定。

Finally, artificial food coloring may be of particular concern for children. It's known that children are more vulnerable to environmental toxins because their bodies are still developing. I and others believe that this concern may extend to synthetic food dyes, especially considering their prevalence in children's food.

最后，人工食用色素可能会特别影响到儿童。众所周知，由于儿童的身体尚在发育阶段，所以他们更容易受到环境毒素的伤害。我和他人都认为，这一担忧可能会涉及到人工食用色素，特别是考虑到其在儿童食品中的普遍性。

A 2016 study found that over 40 percent of food products marketed toward children in one major supermarket in North Carolina contained artificial food coloring. More research needs to be done to examine how repeated exposure to artificial food dyes may affect children.

2016的一项研究发现，北卡罗莱州的一家大型超市面向儿童所销售的超过40%的食品都含有人工食用色素。关于重复摄入多少人工食用色素也许会对儿童造成影响，还需要有更多的研究。

Lowering your risk of colorectal cancer

减少直肠结肠癌的风险

A few treats during the holidays won't cause colorectal cancer. But a long-term diet of processed foods might. While more research is needed on the link between synthetic food dyes and cancer, there are evidence-based steps you can take now to reduce your risk of colorectal cancer.

节日期间摄入为数不多的零食不会引起直肠结肠癌。但是，长期食用加工食品则可能会导致结肠直肠癌。尽管在人工食用色素和癌症之间的联系还需要更多的研究，目前你可以采取一些经过考证的举措来减少自身的结肠直肠癌风险。

One way is to get screened for colon cancer. Another is to increase your physical activity. Finally, you can eat a healthy diet with more whole grains and produce and less alcohol and red and processed meat. Though this means eating fewer of the colorful, ultra-processed foods that may be plentiful during the holidays, your gut will thank you in the long run.

一个方法就是进行直肠癌筛查。另一个就是加强锻炼。最后，健康饮食，更多摄入全谷物和农产品，少饮酒并且控制红肉和加工肉类的摄入。尽管这意味着我们要少吃色彩鲜艳且过度加工的食品（假日期间会非常丰盛），但是从长远来看，你的肠道会感谢你所作出的决定。

来源：ScienceAlert

编辑&翻译：Sarah