有机肉较不容易致癌吗？

Original 能救命的营养学蔬食益生

本视频由格雷格（Michael Greger）医生于 2018 年 7 月 6 日发布，来自NutritionFacts.org — 能救命的营养学。

专家太多，什么样的研究才是靠谱的？(点击了解，你会震惊！）

格雷格（Michael Greger） 医生是畅销书《How Not to Die》作者，中文译本：繁体版书名为《食疗圣经》。简体版书名为《救命》，已于今年7月19日发售，详情见文末。

有机肉较不易致癌吗？

Is Organic Meat Less Carcinogenic?

视频摘要：研究人员测试了76种不同种类的肉类，包括有机肉类和常规肉类，测试33种不同的致癌物质。

Researchers tested 76 samples of different kinds of meat, both organic and conventional, for 33 different carcinogens.

这项研究，与摄入各种肉类的致癌风险有关，被估计出的风险太大了以至我们可能不想喂孩子们吃牛肉、猪肉或鸡肉每月超过5次。

This study, on “the carcinogenic risk associated with the intake of” various meats, estimated the risk was so great that we may not want to feed beef, pork, or chicken to kids more than like five times a month.

这是在欧洲，其中羊肉的污染是一个特殊的问题。

This was in Europe, where lamb contamination is a particular problem.

在美国，如果说有佼佼者的话，那将是鸡和作为一种阻燃剂的多溴联苯醚(简称PBDEs)相比，不仅拿其与其他肉类相比，还包括其他国家在内。

In the United States, if there was any standout, it would be chicken and PBDEs (flame-retardant chemicals) — not only compared to other meats, but other countries.

美国的鸡只，当与其他国家的检测样本比较受污染的程度，是超过多达10-20倍，虽然饮食不是唯一的暴露来源，但那些吃素的人，只有比那些吃肉的人，血液中的水平降低了25％而已，尽管这一比例的主因很大可能原自鸡肉。

U.S. chickens are like 10-20 times more contaminated than the samples taken from other countries that have been tested — though diet is not the only source of exposure, as those eating vegetarian have only about 25% lower levels in their bloodstream than those eating meat, though a large proportion of that may be from chicken.

对于其他化学品，饮食可能会发挥更大的作用。

For other chemicals, diet may play a larger role.

母乳中污染物的研究可以追溯到30多年前的素食主义者，研究发现素食者的一些污染物平均水平只有全国平均水平的1至2％。

Studies of the “pollutants in the breast milk of vegetarians” dating back over 30 years have found the average vegetarian levels of some pollutants were “only 1 to 2 per cent as high as the national average.”

实际上，对于他们所关注的7种污染物中的6种，当中甚至没有在分数的范围内出现重叠；素食者中的最高值仍比一般人口中的最低值来得更低。

In fact, for the six out of seven pollutants they looked at, there wasn’t even overlap in the range of scores; “the highest vegetarian value was lower than the lowest value obtained in the general population.”

推测这是因为这些污染物会随着食物链的上升而增加；所以，通过一路吃食物链下端的东西，也就是植物，那些素食者可能较有优势。

This is presumed to be because these pollutants concentrate up the food chain. So, by eating lots from all the way down the food chain — plants — those eating vegetarian may “have an edge.”

例如，二恶英：肉类、鱼类和乳制品被相信几乎是体内二恶英的暴露源。

For example, dioxins. “Meat, fish, and dairy are believed to contribute almost all of the dioxin body exposure.”

而且，事实上，如果你看看这些严格执行植物性饮食者，他们可能只有约三分之一二恶英和多氯联苯的含量，或甚至少于五分之一在他们的身体内循环。

And, indeed, if you look at those eating strictly plant-based diets, they may only have about a third of the levels of dioxins and PCBs, or even less than a fifth, circulating throughout their bodies.

这项研究真的让我感到震惊。

This study really struck me.

印度一直面临一个重大问题来处理其每年数百万镑的电子垃圾。

“India has been facing a major problem of treating its millions of pounds of electronic waste” every year.

而且，这些贫穷工人在电子废物回收厂可能会暴露到高含量的有毒化学品，以至最终在他们血液内发现如此的PCBs含量是双倍于那些生活在远离海岸线约250英里的人们。

And, these poor workers at these electronic waste recycling plants can be exposed to high levels of toxic chemicals, ending up with this kind of concentration of PCBs in their bloodstream — nearly twice as high as those living about 250 miles away along the coast.

但这些是废物处理厂中，非素食主义者。在同一工厂工作的，素食者的PCB水平甚至比普通的人们更低。

But these were non-vegetarian workers at the waste plant. The PCB levels of the vegetarians working at the same plant was even lower.

这些横断面研究所面对的问题就是我们不能把饮食甄拔出来。也许素食主义者有其他生活方式起到了防护作用。

The problem with these cross-sectional studies is that we can’t single out the diet. Maybe vegetarians have other lifestyle behaviors that protect them.

你无从知道答案，直到...你将之进行测试。

You don’t know until you put it to the test.

改变人们的饮食，再看看会发生什么。

Change people’s diets and see what happens.

这对持久性污染物是很难做到像PCBs可能需要几十年方能从身体解毒，但我们可以摆脱重金属，像汞，只需几个月内便可解毒。

That’s hard to do with persistent pollutants like PCBs, which may take literally decades to detoxify from the body. But, we can get rid of heavy metals, like mercury, in a matter of months.

事实上，在3个月内当排除摄入肉类、家禽、鱼类和蛋类，自他们的身体中出现了一个明显的有毒重金属的含量下降，当中包括水银、镉和铅。3个月内下降高达约30％。

And, indeed, within three months of “the exclusion of meat, poultry, fish and eggs” from their diets, there was a significant drop in the levels of toxic heavy metals in their bodies, including mercury, cadmium, and lead.” Up to about a 30% drop within three months.

如果我们坚持服用有机肉类呢？

What if we just stick to organic meat?

有机认证的肉类来自有机饲养的家畜其饲料不含杀虫剂和法律规定的动物副产品。因此，人们会假设在那里应该会出现一个较低化学残留物的积累。但是，从实践层面来看，根本就没有研究有机肉中的化学残留物含量，直到......现在。

Certified organic meat comes from “livestock that are fed with organically produced feed that is free of pesticides and animal by-products,” by law. Therefore, one would assume “that there should be a lower accumulation of chemical residues.” However, on a practical level, there were simply “no studies on the chemical residues’ content in organic meat” — until, now.

研究人员获得了76个不同种类的肉类样本，有机和常规的均有，并量化其33种不同的致癌性和持久性有机污染物的污染程度。

Researchers “acquired 76 samples of different kinds of meat, both organic and conventional, and “quantified their levels of contamination with 33 different carcinogenic persistent organic pollutants.”

毕竟，食物的摄入贡献超过90％的有关这些化合物的总暴露量，特别是源自动物的食物。

After all, “the ingestion of food contributes more than 90% to the total current exposure to these compounds, especially food of animal origin.”

另一方面，越来越多的消费者选择有机食物。事实上，有机食品的产量在过去十年中增加了约50％;

“On the other hand, an increasing number of consumers” are choosing organic. In fact, “organic food production increased by 50% during the last decade.”

那么，有机肉类的消费者是否受到保护？

So, are consumers of organic meat protected, or not?

好的，“没有任何样品是完全免于致癌污染物的”，这是可预计的，毕竟我们的世界是如此的受污染。但令人惊讶的是，“有机和非有机生产的肉类之间的差异是很少的。”此外，从目前的肉类消费模式看来，任何一种摄入方式都是超标的。

Well, “no sample was completely free of carcinogenic contaminants,” which is to be expected, given how polluted our world is these days. But, what was surprising was that “the differences between organically and conventionally produced meats were minimal.” Furthermore, “the current pattern of meat consumption exceeded the maximum limits” either way.

引人注目的是有机肉的摄取不仅无法减少这种致癌风险，有时甚至被发现来得更高。

“Strikingly, the consumption of organically produced meat not only does not appear to diminish this carcinogenic risk,” but was sometimes found to “be even higher.”

结果，可悲的是摄取有机肉并不会减少与这些污染物的摄入量相关的致癌潜力。

Bottom line, sadly, is that the “consumption of organic meat does not diminish the carcinogenic potential associated with the intake of these pollutants.”

翻译： Kok Heung Chung

编辑： Karen Chou (老玉米)

参考文献：

Hernández ÁR, Boada LD, Almeida-González M, et al. An estimation of the carcinogenic risk associated with the intake of multiple relevant carcinogens found in meat and charcuterie products. Sci Total Environ. 2015;514:33-41.
Srikumar TS, Källgård B, Ockerman PA, Akesson B. The effects of a 2-year switch from a mixed to a lactovegetarian diet on trace element status in hypertensive subjects. Eur J Clin Nutr. 1992;46(9):661-669.
Hall RH. A new threat to public health: organochlorines and food. Nutr Health. 1992;8(1):33-43.
Hergenrather J, Hlady G, Wallace B, Savage E. Pollutants in breast milk of vegetarians. N Engl J Med. 1981;304(13):792.
Schecter A, Paepke O. Comparison of blood dioxin, dibenzofuran and coplanar PCB levels in strict vegetarians (vegans) and the general United States population. Organohalogen Compd. 1998;38:179-182.
Fraser AJ, Webster TF, McClean MD. Diet contributes significantly to the body burden of PBDEs in the general U.S. population. Environ Health Perspect. 2009;117(10):1520-1525.
Huwe JK, Larsen GL. Polychlorinated dioxins, furans, and biphenyls, and polybrominated diphenyl ethers in a U.S. meat market basket and estimates of dietary intake. Environ Sci Technol. 2005;39(15):5606-5611.
Eguchi A, Nomiyama K, Devanathan G, et al. Different profiles of anthropogenic and naturally produced organohalogen compounds in serum from residents living near a coastal area and e-waste recycling workers in India. Environ Int. 2012;47:8-16.
Hernández ÁR, Boada LD, Mendoza Z, et al. Consumption of organic meat does not diminish the carcinogenic potential associated with the intake of persistent organic pollutants (POPs). Environ Sci Pollut Res Int. 2017;24(5):4261-4273.