为什么红肉会增加患癌症的风险

为什么红肉会增加患癌症的风险

Health experts have known for years that the consumption of red meat raises a person's cancer risk, but it took time to understand why.

健康专家多年来就知道，食用红肉会增加患癌症的风险，但他们需要时间来理解其中的原因。

Turns out it's not the fat in red meat that increases cancer risk. Nor is it the cholesterol or the way we grill our burgers and steak. It's the sugar.

事实证明，并不是红肉中的脂肪增加了患癌症的风险，也不是胆固醇或者我们烤汉堡和牛排的方式，而是糖。

Researchers at the University of California, San Diego discovered that the reason red meat is linked to higher cancer risk is that it contains a sugar molecule — specifically Neu5Gc — that's not naturally found in the human body. When the immune system spots this sugar molecule, it attacks it, and it's inflammation from this attack that, over time and continued exposure, raises a person's lifetime risk for cancer.

加州大学圣地亚哥分校的研究人员发现，红肉与更高的癌症风险有关的原因是，红肉含有一种糖分子——特别是Neu5Gc——这在人体中并不天然存在。当免疫系统发现这种糖分子，它就会攻击它，而正是这种攻击引发的炎症，随着时间的推移和持续的暴露，会增加一个人患癌症的终生风险。

As with many health issues, the problem with red meat is sugar and the body's reaction to a particular molecule. (Photo: Ronald Sarayudej [CC BY 2.0]/Flickr)

What's more, Neu5Gc is found in beef, pork, lamb and bison. However, it's not found in chicken or fish — two sources of meat that aren't linked to an increased cancer risk. It's also found in fish eggs (caviar,) as well as whole milk and certain cheeses.

此外，Neu5Gc还存在于牛肉、猪肉、羊肉和野牛中。然而，在鸡肉和鱼肉中却没有发现这种物质——这两种肉的来源与增加癌症风险无关。它也存在于鱼卵(鱼子酱)、全脂牛奶和某些奶酪中。

Previously, health experts believed that it was the grilling of red meat that led to the increase in cancer risk. But researchers couldn't understand why grilling chicken and fish didn't also lead to an increased risk. Now, they have a better understanding of why.

此前，健康专家认为，烧烤红肉会增加患癌症的风险。但研究人员无法理解为什么烤鸡和烤鱼不会增加患病风险。现在，他们对原因有了更好的理解。

Contrary to popular belief, it's not your grill that increases the cancer risk of eating red meat. (Photo: senk/Shutterstock)

Dr. Ajit Varki, the lead author of the study, said the Neu5Gc phenomenon is unprecedented, explaining that Neu5Gc is the "gasoline on the fire" — meaning it doesn't directly cause cancer, but it boosts the risk for the disease.

这项研究的主要作者阿吉特·瓦尔基博士说，Neu5Gc现象是前所未有的，他解释说，Neu5Gc是“燃烧的汽油”，这意味着它不会直接导致癌症，但会增加患病的风险。

What about chicken?

鸡肉怎么样?

For those wondering if they should stop eating red meat? Varki doesn't think so. He recommends using moderation when choosing red meat and limiting consumption to two or three servings per week. Interestingly, Varki doesn't eat meat himself, but he does eat poultry and fish. A more recent study may give credence to his approach.

对于那些想知道是否应该停止吃红肉的人来说，瓦尔基不这么认为。他建议在选择红肉时要适度，并将每周的摄入量限制在两到三份。有趣的是，瓦尔基自己不吃肉，但他吃家禽和鱼。最近的一项研究可能会证实他的方法。

Roasted chicken is easy to make — and it gets points from these medical studies. (Photo: Africa Studio/Shutterstock)

Researchers working with Dale Sandler, PhD, of the National Institute of Environmental Health Sciences, found while eating red meat may increase the risk of breast cancer, eating poultry has the opposite effect. Their work was published in International Journal of Cancer.

与美国国家环境健康科学研究所的戴尔·桑德勒博士合作的研究人员发现，虽然吃红肉可能增加患乳腺癌的风险，但吃家禽却有相反的效果。他们的研究发表在《国际癌症杂志》上。

They followed the meat eating and cooking practices of 42,012 women — part of the Sister Study, which studies sisters and their breast cancer link— who were followed for an average of 7.6 years. The contrast was clear, according to Science Daily: Those who ate the most red meat had a 23% higher risk when compared with those who consumed the least. On the other side of the equation was similar: Those who at the most poultry had a 15% lower risk than those who ate the least.

研究人员对42,012名女性的吃肉和烹饪习惯进行了平均7.6年的跟踪调查。这是姐妹研究的一部分，研究吃肉习惯和她们患乳腺癌之间的关系。据《科学日报》报道，这种对比很明显:那些吃红肉最多的人与那些吃红肉最少的人相比，患病风险要高出23%。在等式的另一边是相似的:那些食用最多家禽的人比那些食用最少家禽的人患病风险低15%。

Sandler said they don't know why the poultry had such a positive effect, but even without that information, it's becoming clearer that eating less red meat or eliminating it may reduce your cancer risk.

桑德勒说，他们不知道为什么家禽有如此积极的影响，但即使没有这些信息，越来越清楚的是，少吃红肉或不吃红肉可能会降低患癌症的风险。