In a few words: The World Health Organization says smoked meat is a type of carcinogen and there is sufficient evidence that it causes colon cancer!

Niu Niu: The Chinese New Year is coming soon, and my mother is preparing smoked bacon again. But I heard a saying that "1 piece of smoked bacon = smoking 290 cigarettes", how can I eat it during the Chinese New Year?

Binghai: You can't just believe everything you hear. That statement is just an analogy. It doesn't mean that eating a piece of bacon is as harmful as smoking 290 cigarettes. And cigarettes have many harmful ingredients, mainly tar. If you eat a whole piece of bacon in a day, it may not be a big deal, but if you smoke 290 cigarettes a day, I think you will probably need to go to the hospital.

Niu Niu: However, processed meat is a type of carcinogen, which has been clearly announced by the World Health Organization. Even if it is not as toxic as cigarettes, it is still toxic enough, right?

Binghai: You may have a misunderstanding that carcinogens are classified by toxicity. In fact, a class of carcinogens means that there is a clear risk of cancer. For example, tobacco, betel nut, arsenic, etc. Class 2A means that there is a clear risk of cancer in animal experiments, and it may theoretically cause cancer in humans, but the experimental evidence is not sufficient at present, such as burning wood, high-temperature fried foods, and beverages over 65 degrees Celsius. Class 2B means that there is only some insufficient evidence in both animals and humans, such as kimchi, coffee, dichlorvos, etc. Class 3 and Class 4, then the evidence is even smaller. Back to processed meat products, let me give you a definition first: processed meat products refer to meat that has been salted, air-dried, fermented, smoked, or otherwise processed to increase flavor or improve preservation. The International Agency for Research on Cancer Working Group concluded that there is "sufficient evidence" in epidemiological studies that eating processed meat products causes colorectal cancer, that is to say - eating processed meat products can cause colorectal cancer. In addition, eating processed meat products also shows a correlation with gastric cancer, but the evidence is not conclusive.

Niu Niu: Oh, I understand. What is said about various carcinogens is “sufficient evidence” rather than harmfulness.

Binghai: Yes, and the above only talks about the dimension of "carcinogenic risk", and does not mention other toxicity. For example, although betel nut is a Class I carcinogen, it is obvious that you may not be in trouble if you chew a bag a day, and although dichlorvos is a Class 2B, if you really drink a bottle, I don't know whether you will get cancer, but if you don't see a doctor, you will see death. Of course, I am just making an analogy, don't try it, it will really become a Class 2B.

Niu Niu: Tsk… Then how should we view these carcinogens? For example, should we really not eat smoked bacon during the Chinese New Year? After all, its risks are very clear.

Binghai: I dare not say what should be done. I can only say that we advocate that these carcinogens should not be touched if possible.

Niu Niu: But many people can't do it. It is almost impossible to advocate not eating bacon during the New Year, people of some ethnic groups not eating kimchi, and grandfathers not drinking hot tea.

Binghai: I understand that everyone has different values. If they are willing to ignore the risks, what is your business? If you insist on instilling in them "you should", it will only cause disgust and they will not listen, which will lose the meaning of popularizing science.

Niu Niu: But I find it strange. Now this causes cancer, and that causes cancer. Why did I rarely hear about people around me getting cancer in the past? Are there more and more cancer cases now?

Binghai: Well, the World Health Organization's International Agency for Research on Cancer released its latest report in September 2018, saying that they estimate that the number of people suffering from cancer worldwide is "rapidly increasing", with 18.1 million new cases and 9.6 million deaths in 2018 alone. By the end of the 21st century, cancer will become the world's number one "killer" and the biggest "stumbling block" to extending human life expectancy. But what you may not expect is that in economically developed Europe, cancer cases and cancer deaths account for 23.4% and 20.3% of the global total, respectively, but its population accounts for only 9% of the world's total population.

Niu Niu: Is it because of the serious industrial pollution in Europe or bad living habits?

Binghai: Let me give you a set of data. In 1820, the average life expectancy in Western Europe was 36 years old, which reached 65 years old in 1950, and now it is 77.5 years old. In 1949, the average life expectancy in China was less than 35 years old, and in 2018, it was 77 years old. There is another hard-core data: the peak age of cancer incidence is mostly 70-75 years old.

Niu Niu: It turns out that fewer people suffered from cancer in the past because people generally did not live to the age when cancer is most prevalent.

Binghai: There is another reason. The improvement of information technology has enabled the comprehensive and accurate statistics of the number of cancer cases in various places. The improvement of living standards and the wide coverage of medical insurance have also led to an increase in the number of patients seeking medical treatment and the number of confirmed cases. These have all led to a significant increase in the statistics of cancer patients. However, even with cancer, more and more people are living a long life and a good quality of life through advanced treatment methods. With the development speed of modern medicine in the past 10 to 20 years, we can no longer look at cancer with the previous impression.

Niu Niu: Does this mean that conquering cancer is just around the corner?

Binghai: It will take some time. In fact, the WHO report also said: Some cancers can be prevented, and prevention efforts are mainly focused on those risk factors that we are familiar with: alcoholism, smoking, lack of physical exercise, and unhealthy eating habits. For example, eating less smoked bacon can reduce the incidence of colorectal cancer.

Niu Niu: You said that even if we conquer cancer one day, there will probably be other diseases that will make us unable to live too long. Is there some force that does not want people to live too long and creates one disease after another? Will we offend something if we keep conquering diseases?

Binghai: Don’t let your imagination run wild. The so-called diseases, or health problems, are defined by ourselves. If we really follow the will of nature, after we give birth to a baby and raise him to be able to live independently, we may have no value and should not even live to 40 years old. So “God is in his heaven, all right with the world.” Conquering diseases is the great responsibility of scientists and doctors. With the extension of life expectancy, no matter what great changes occur in the nature of human beings as biological beings in the future, it means the advancement of the next wave. We old antiques who can only live for more than 80 years should not use our own values ​​to judge future humans.

Niu Niu: Uh, are we getting off topic?