肺癌

有些食物能够致癌（例如发霉的食物），有些能够防癌（如大蒜）。世界癌症基金会2007报告建议四所谈的是植物性食物（粮食、蔬菜、水果）致癌和防癌的问题。植物其实相当复杂，含有10万种不同化合物，有的称做“植物化学物质phytochemicals”。这些化合物决定了植物的属性和特征。有很多成分及其作用还未完全知晓。这也是用人造的代替品（例如维生素）不能完全替代植物食物的原因。我们现在仍然处在学会鉴别有益有害的阶段。
黄曲霉素和膳食纤维素
食物致癌，首先想到肝癌。完好的粮食本来不会引发癌症。问题是发霉。发霉产生黄曲霉菌是引发肝癌的重要原因之一。这一点读者大都知晓。除了粮食发霉，花生也是一个主要的可发霉产生黄曲霉菌的食物。在这份专家报告中，发霉产生的黄曲霉菌引发肝癌的结论，被评定为“确信”级。世界上只有欧洲和澳洲这个问题比较少，非洲、东南亚、中国是高发地区，美国也比欧洲略高。发霉不仅仅产生黄曲霉素，而且产生很多其他种类的毒素（例如串珠镰刀菌、杂色曲菌、圆弧青菌、娄地青菌、念珠菌、白地菌），它们可以致癌，还与亚硝酸胺协同致癌。
腌制食品是另一个黄曲霉菌毒素的来源，品种就太多了，数不胜数。虽然各个国家都有一些检验标准，问题难在监测和管制。特别是食品工业是小生产的地方很难监管。所以对这个问题远远没有找到清楚的解决办法。而且，究竟摆在你面前的哪些具体的食物有问题？除非看见发霉迹象，恐怕很难由消费者自己判断。所以只有尽力而为，小心选择食物，自求多幅。但是，也不要草木皆兵。
用食物降低癌症风险，有很多选择。我想谈谈纤维素，因为熟悉它的人还不多。2007癌症基金会报告评价膳食纤维素降低结肠癌风险，评价级别是“很可能”级。有一点要说明，就是所谓“膳食纤维素”并不是指植物的纤维，不是那种肉眼可见的一丝一缕的东西，而是指多糖纤维素（polysaccharides，按照世界卫生组织最近的新定义），是植物细胞壁主要部分。来源是粗粮、豆类、蔬菜、水果。不在细粮和果汁里面。肉眼也看不出来的。
膳食纤维素在肠道遇水膨胀成网状，吸附过多的脂肪和糖等，随大便排出。而且，因为它使得肠蠕动加快，有毒和致癌物也快速通过，降低肠癌风险。至于多吃看得见的纤维（如芹菜、豆荚），有时反会大便不通。这份报告还提到，非洲人的结肠癌、糖尿病、心脏病发病率低，而他们的排便多呈大堆状或者半干状，是与他们多吃粗粮有关。另外有资料说非洲成年人每日大便约450克，英国人不足200克。后者肠癌高发。也许，大便反常地硬而少，值得警惕。
(附言：我有位友人身体非常健壮，肌肉隆起，精力无穷。多年大便量少而硬，他认为自己身体强壮，这现象必是消化吸收功能特棒的结果。不料中年竟死于直肠癌。令人唏嘘。今天看，他要是多吃膳食纤维素，便多而松，也许可以避免吧?)
读者不要轻视这个小小纤维素，它与预防癌症、糖尿病、心脏病都有关。国内外市场都有食品级的膳食纤维素，觉得饮食不足以解决问题的人，不妨思考是否需要补充膳食纤维素。
蔬菜预防癌症的实验研究评价
这样写下去怕会太长了。制作一个表来汇总植物食物的实验吧。我把这份专家报告中蔬菜降低癌症风险的实验评价结果列入一个表内，可以一目了然。
表中癌分11种，
评价级别分“确信”、“很可能”、“证据有限提示”、“无作用”四类。
食物分不含淀粉的蔬菜、葱类、胡萝卜、水果、含类胡萝卜素类、含胡萝卜素类、含维生素B6类、含维生素C类、含维生素E类、含番茄素类、含硒类、含槲皮素类、豆类，一共13种，都是人家实验所用的材料。

 植物性食物是否降低癌症风险实验结果评价

1)唯一评上“确信”级的是水果预防肺癌。恰恰也是人们不太确知的。
2)评上“很可能”级的有15项，共7种植物食物很可能可以预防癌症。
3)膳食纤维素不是单独的天然食物，没有列入本表。
4)本来看好槲皮素预防肺癌，这个结果(证据有限)让人失望。苹果皮含槲皮素有利预防肺癌一直是热门话题的。不过，水果预防肺癌是“确信”级的结论，应当包含槲皮素的贡献。
上述结果是对过去的实验进行评价，不等于穷尽了所有的可能性。随实验的增加，会有新的结果出来。如果你接受世界癌症基金会的这项研究报告，暂时可以用这个表选择适当的预防癌症的植物性食物。2008年夏天世界癌症基金会要发表另外的研究结果，可以期待有新的信息。

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Some foods can cause cancer (such as moldy food), and some can be anti-cancer (such as garlic). World Cancer Fund 2007 report recommended that four to talk about the plant food (grain, vegetables, fruits) carcinogenic and anti-cancer issues. Plants in fact very complex, contains 10 million different compounds, some known as "phytochemicals phytochemicals". Of these compounds determines the properties and characteristics of the plant. There are many elements and its role is not fully known. It is also used artificial substitutes (such as vitamins) can not entirely replace plant food causes. We are still useful in identifying harmful to the stage of society.
As aflatoxin and dietary fiber
Food carcinogenic, first thought of liver cancer. Good food would not have cause cancer. The problem is mildew. Aspergillus flavus is a mold produces an important cause liver cancer, one of the reasons. This is generally known to the reader. In addition to grain mold, peanut is also a major that can produce aflatoxin moldy food. In this expert report, produced by Aspergillus flavus mold cause liver cancer findings were rated as "satisfied" grade. The world, only in Europe and Australia, this issue is relatively small, Africa, Southeast Asia, China is a high-prone areas, the United States is slightly higher than in Europe. Mold not only produce aflatoxin, but also creates many other types of toxins (eg, Fusarium moniliforme, Aspergillus versicolor, arc green bacteria, Lou to green fungus, candida, white, bacteria), they can cause cancer, but also with synergistic carcinogenic amine nitrite.
Preserved foods is another source of Aspergillus flavus toxin varieties on too many numerous. Although each country has some of the test, the problem is difficult in the monitoring and control. Especially in food industry is a place where small-scale production is difficult to control. So far on this issue did not find a clear solution. Moreover, what put in front of you which specific foods have questions? Unless to see signs of mildew, I am afraid is very difficult for consumers to judge for themselves. Therefore, only best-effort and careful food choices, self-seeking multiple. However, do not panic.
With food to reduce cancer risk, there are a lot of choices. I would like to cellulose, because not many people are familiar with it. 2007 Cancer Fund report assesses the dietary fiber reduces colon cancer risk, assessment level is "very likely" level. One thing to note is the so-called "dietary fiber" does not mean that the plant fiber, not the visible trace of the kind of thing, but to polysaccharide cellulose (polysaccharides, according to a new definition of the World Health Organization), is a major part of plant cell walls. Source of coarse grains, beans, vegetables and fruit. Flour and rice and fruit juices are not inside. Naked eyes can not see out of.
Dietary fiber in the intestinal water swelling into the mesh, the adsorption excess fat and sugar, with the stool discharge. And, because it makes the bowel movements accelerated the rapid adoption of toxic and carcinogenic to reduce colon cancer risk. As for the visible eat fiber (such as celery, legumes), and sometimes it will run stool unreasonable. The report also mentioned that Africans colon cancer, diabetes, heart disease rate is low, and their defecation Duocheng-shaped or semi-shaped piles, is related to their eating roughage. In addition there is information that the adults in Africa is about 450 grams per day stool, the British less than 200 grams. The latter high incidence of colon cancer. Perhaps the stool hard and less abnormal and warrants vigilance.
(Postscript: I had a friend physically very robust, muscular uplift, energy infinite. For many years with low stool hard, he considers himself physically strong, this phenomenon is the digestion and absorption must be the result of special rods. Unexpectedly, middle-aged actually died of rectal cancer. cause for regret. today that, if he was eating dietary fiber, they are many and pine, perhaps to avoid it?)
Readers are cautioned not underestimate this small cellulose, it is the prevention of cancer, diabetes, heart disease, are related to. Both domestic and foreign markets food-grade dietary fiber, that diet will not solve the problem, you might think whether it is necessary to add dietary fiber.
Vegetables and cancer prevention study and evaluate the experimental
Fear that they will go on like this for too long. Produce a table summary of plant experimental food bar. I put this expert report and vegetables reduce the risk of cancer of the experimental results of the evaluation included a table, you can at a glance.
Carcinoma of the table in 11 species,
Evaluation level into "confident," "likely," "there is limited evidence Tips", "no effect" four.
Non-food sub-starch vegetables, onions, carrots, fruits, including Carotenoids containing carotenoids classes, including vitamin B6 classes, including vitamin C, vitamin E classes, including tomatoes prime category, Se-class, quercetin classes, beans, a total of 13 species, all others used in experimental material.

1) The only assessed "convinced" level is the fruit to prevent lung cancer. This is exactly what people do not really know.
2) assess the "very likely" level of 15 counts, a total of seven kinds of plant foods is likely to prevent cancer.
3) dietary fiber is not a single natural food, not included in this table.
4) have been optimistic about quercetin to prevent lung cancer, the results (limited evidence) disappointing. Pingguo Pi-containing quercetin has been beneficial to prevent lung cancer, a hot topic. However, the fruit to prevent lung cancer is "confident" level of the conclusion should include the contribution of quercetin.
The results of the experiment is to evaluate the past does not mean that exhausted all the possibilities. With the increase of the experiment, there will be a new outcome. If you accept this the World Cancer Research Fund report, the temporary can use this menu, choose the appropriate plant food to prevent cancer. Summer of 2008, the World Cancer Research Fund to be released the results of another, you can look forward to new information.