Why is gastric cancer a great threat to East Asians?

Not long ago, a message appeared on Weibo describing the lunch of Korean kindergarten children. In a large number of photos, we see all kinds of kimchi. There are many Chinese parents feeling: too unhealthy!

Indeed, pickled foods are usually high in salt and pose a variety of health threats. In addition, some pickled foods also contain nitrite, which has the risk of causing cancer. As a result, China no longer provided large quantities of pickled food in school meals at least 20 years ago. When I was at school, I hardly ever ate kimchi or pickled meat at school.

However, China still has a high incidence of gastric cancer. China accounts for 1/5 of the world’s population, but stomach cancer accounts for nearly half of the world’s incidence. Not only in China, but also in various statistics, several countries in East Asia, especially China, Japan and South Korea, have a relatively serious phenomenon of gastric cancer.

The incidence and mortality of gastric cancer in China ranks second among malignant tumors, with an incidence of 31.28 per 100,000 people, of which the incidence in males is twice as high as that in females. About 679,000 new cases and 498,000 deaths are reported each year.

Why is that?

Eating habits: high-salt and pickled foods

Although not as serious as South Korea, China and Japan also have a large number of cultures and habits of eating pickled food. The Japanese have a habit of eating pickled fish. On the southeast coast of China, a condiment called “fish sauce”, which can add freshness and saltiness to food, is widely used.

Fish sauce is made from fragments of fish and shrimp, as well as a lot of salt. There is no doubt that this is a very unhealthy condiment, but long-term cooking habits are difficult to change.

Decades ago, in inland China, such as the northwest, North China and Northeast China, once winter came, the supply of fresh vegetables is a problem. Of course, in the 21st century, these historical problems have long been solved, but the eating habits of northern Chinese have not changed so quickly. Most northerners still have the problem of overusing sauce and eating pickles and bacon in winter.

Of course, in the West, pickles and bacon also have a long history. But on the other hand, the development of the West is earlier, the popularity of refrigerators is much earlier than in East Asia, and a large number of pickled foods have been gradually replaced by fresh fruits and vegetables. In developing countries like China, the popularity of refrigerators has only been around since the end of the 20th century, and many people’s eating habits have not changed.

Excluding the influence of pickled foods, other diets in East Asia also have the hidden worry of high salt content. If you have traveled to Japan, you are probably familiar with Japanese food, which is often very salty. In many parts of China, some popular dishes are also high in salt. For example, Sichuan cuisine, which is very familiar to everyone and is very representative of Chinese food. Because spicy dishes are very spicy, they often make diners overlook another problem: they are also often very salty.

It will take longer to change these habits. Perhaps, Chinese people are unwilling to change these eating habits, or it is difficult to change, and there is a reason for this.

In the city, the rapid development of China, wage earners have a relatively high work intensity, longer working hours and greater mental pressure. The working and living environment worsened their eating habits:

1. Their working hours are chaotic, their diet is irregular, the rate of eating packaged food and simple fast food is too high, and they are short of fresh fruits and vegetables.
2. They are under great mental stress and like to eat some food with a stimulating taste to relieve the stress, resulting in excessive salt intake.
3. Some jobs that require frequent social interaction, such as marketing and salespeople, attend too many banquets and eat a lot of unhealthy food and alcohol.

These problems are the same in Japan and South Korea, which may also explain why Japanese and South Koreans also have more serious stomach cancer.

But China also has vast rural areas and a large agricultural population. In southern China, the latitude is low, the climate is close to the subtropics, and it is often very hot when working during the day. At this time, some peasant workers sweat a lot, and it is reasonable that their food becomes more salty in order to replenish salt.

Therefore, it is unwise and unsympathetic to accuse Chinese people of unhealthy eating habits without considering the specific living environment of Chinese people.

Helicobacter pylori

The infection rate of Helicobacter pylori is relatively high in China. In many statistics, more than half of China’s residents are infected with Helicobacter pylori.

Helicobacter pylori infection may be related to the living habits of Chinese people. Although there is a lack of particularly precise research, some people think that Chinese people sitting around eating together and picking up food with chopsticks from public plates may make Helicobacter pylori more infectious.

Although this is probably also a misunderstanding. Because, in fact, Chinese people pick up food from public plates only when they are having dinner with their families. While at work, when eating on their own or in the canteen, Chinese people generally adopt the separate meal system.

In addition, even if the separate meal system is not adopted, sometimes Chinese people will set up “public chopsticks”, which are only used to pick up food and do not touch anyone’s mouth, which can also avoid spreading diseases.

Therefore, the absence of separate meals may indeed lead to some Helicobacter pylori infection, but it is not enough to become the main cause of infection. In more studies, the Chinese have found that people infected with Helicobacter pylori are also poorer people in China, such as low-income farmers and the unemployed.

These infected people often live in groups and lack modern health knowledge, or although they understand it, they do not pay enough attention to it. They may have poor living conditions, and even have bad habits such as sharing water cups. This increases their risk of contracting the disease.

Lack of health knowledge has also led to some infections that could have been avoided. In some surveys, children are highly likely to be infected with Helicobacter pylori. Studies have found that those mothers are often infected, and they have the habit of chewing food before feeding their children.

Fewer physical examination habits

Unlike Japan, the incidence of gastric cancer in China is very high, and the mortality rate is especially high. Why is that?

Some experts pointed out that gastric cancer in Japan is often found in the early stage, while many Chinese patients with gastric cancer are not detected until the advanced stage of gastric cancer. This leads to a very low cure rate and a higher likelihood of death.

It must be recognized that China is a developing country, and many people do not have the habit of taking regular medical examinations, nor do they objectively have the time and money to participate in medical examinations every year. Employees who work in a company can usually enjoy free medical examinations organized by the company, but many Chinese do not work in a company or have not signed a labor contract with their employers, so they lack the opportunity to have a medical examination themselves.

When gastric cancer shows obvious symptoms, treatment is usually too late. About 90% of gastric cancer found in China belongs to advanced stage, and the prognosis of advanced gastric cancer is closely related to the timing of diagnosis and treatment. Even after surgical operation, the 5-year survival rate of advanced gastric cancer is still less than 30%. The 5-year survival rate of early gastric cancer after treatment can exceed 90%, and even achieve the cure. The diagnosis and treatment rate of early gastric cancer in China is less than 10%, which is much lower than that in Japan (70%) and South Korea (50%).

There is another difference. Japanese and South Koreans are aware of their high incidence of gastric cancer, so they organize a special gastric cancer screening work earlier. Japan began to organize national gastric cancer screening in 1983, while South Korea began in 1999. These two countries have higher early screening rates for gastric cancer, and many patients with early gastric cancer can be detected in advance. However, China’s construction in this area started relatively late.

The low screening rate may also lead to miscalculation of the data. In some statistics, the incidence of gastric cancer in China is slightly lower than that in Japan, but this may also be because the early screening rate in Japan is much higher than that in China. In short, the actual harm in China may be more serious than statistics.

Things are getting better and better

There are other reasons that may lead to a high incidence of gastric cancer in China, such as genetic differences. But this is not a very critical factor, and it is difficult to change, so we don’t need to analyze it.

In fact, all the situations mentioned above are improving. In terms of diet, young people in China have gradually got rid of the habit of eating pickled food. Although the high-salt diet still has a broad basis, we believe that as the working conditions of the Chinese people improve, the pressure of life is reduced, and the spicy and high-salt foods with irritating tastes will gradually move away from the daily diet of the Chinese people.

Solving the problem of Helicobacter pylori requires not only faster and better popularization of medical and health knowledge, but also continuous improvement of the living and working conditions of the poor. In solving the problem of poverty, China is one of the most successful countries in the world.

In terms of physical examination, with the economic development and the popularity of the modern way of life, more and more Chinese people have begun to establish the habit of physical examination-along with mental health care and fitness habits. In addition, China has now recommended people over the age of 40 to participate in gastric cancer screening, which is similar to the practice in South Korea and Japan.

Of course, due to a variety of geographical and historical reasons, we believe that the incidence of gastric cancer in East Asia will continue to be a headache in the foreseeable future. However, China can also gradually catch up with Japan and South Korea to reduce the death rate of gastric cancer. This may be what the Chinese government and the Chinese people can achieve.