為什么紅肉會(huì)增加患癌癥的風(fēng)險(xiǎn)

為什么紅肉會(huì)增加患癌癥的風(fēng)險(xiǎn)

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.

健康專(zhuān)家多年來(lái)就知道，食用紅肉會(huì)增加患癌癥的風(fēng)險(xiǎn)，但他們需要時(shí)間來(lái)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.

事實(shí)證明，并不是紅肉中的脂肪增加了患癌癥的風(fēng)險(xiǎn)，也不是膽固醇或者我們烤漢堡和牛排的方式，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.

加州大學(xué)圣地亞哥分校的研究人員發(fā)現(xiàn)，紅肉與更高的癌癥風(fēng)險(xiǎn)有關(guān)的原因是，紅肉含有一種糖分子——特別是Neu5Gc——這在人體中并不天然存在。當(dāng)免疫系統(tǒng)發(fā)現(xiàn)這種糖分子，它就會(huì)攻擊它，而正是這種攻擊引發(fā)的炎癥，隨著時(shí)間的推移和持續(xù)的暴露，會(huì)增加一個(gè)人患癌癥的終生風(fēng)險(xiǎn)。

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還存在于牛肉、豬肉、羊肉和野牛中。然而，在雞肉和魚(yú)肉中卻沒(méi)有發(fā)現(xiàn)這種物質(zhì)——這兩種肉的來(lái)源與增加癌癥風(fēng)險(xiǎn)無(wú)關(guān)。它也存在于魚(yú)卵(魚(yú)子醬)、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，健康專(zhuān)家認(rèn)為，燒烤紅肉會(huì)增加患癌癥的風(fēng)險(xiǎn)。但研究人員無(wú)法理解為什么烤雞和烤魚(yú)不會(huì)增加患病風(fēng)險(xiǎn)?，F(xiàn)在，他們對(duì)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.

這項(xiàng)研究的主要作者阿吉特·瓦爾基博士說(shuō)，Neu5Gc現(xiàn)象是前所未有的，他解釋說(shuō)，Neu5Gc是“燃燒的汽油”，這意味著它不會(huì)直接導(dǎo)致癌癥，但會(huì)增加患病的風(fēng)險(xiǎn)。

What about chicken?

雞肉怎么樣?

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.

對(duì)于那些想知道是否應(yīng)該停止吃紅肉的人來(lái)說(shuō)，瓦爾基不這么認(rèn)為。他建議在選擇紅肉時(shí)要適度，并將每周的攝入量限制在兩到三份。有趣的是，瓦爾基自己不吃肉，但他吃家禽和魚(yú)。最近的一項(xiàng)研究可能會(huì)證實(shí)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.

與美國(guó)國(guó)家環(huán)境健康科學(xué)研究所的戴爾·桑德勒博士合作的研究人員發(fā)現(xiàn)，雖然吃紅肉可能增加患乳腺癌的風(fēng)險(xiǎn)，但吃家禽卻有相反的效果。他們的研究發(fā)表在《國(guó)際癌癥雜志》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.

研究人員對(duì)42,012名女性的吃肉和烹飪習(xí)慣進(jìn)行了平均7.6年的跟蹤調(diào)查。這是姐妹研究的一部分，研究吃肉習(xí)慣和她們患乳腺癌之間的關(guān)系。據(jù)《科學(xué)日?qǐng)?bào)》報(bào)道，這種對(duì)比很明顯:那些吃紅肉最多的人與那些吃紅肉最少的人相比，患病風(fēng)險(xiǎn)要高出23%。在等式的另一邊是相似的:那些食用最多家禽的人比那些食用最少家禽的人患病風(fēng)險(xiǎn)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.

桑德勒說(shuō)，他們不知道為什么家禽有如此積極的影響，但即使沒(méi)有這些信息，越來(lái)越清楚的是，少吃紅肉或不吃紅肉可能會(huì)降低患癌癥的風(fēng)險(xiǎn)。