Nearly half of the world's gastric cancer patients are in China, and it's because they love to eat pickled vegetables?

China is a country with a rich food culture. Even pickled vegetables have many varieties. People from all over the country use their own methods to make pickled vegetables as daily snacks.

The pickles, salted vegetables, sauerkraut and kimchi we usually eat are all collectively called pickled vegetables. Famous ones include Northeastern sauerkraut, Sichuan kimchi, Fuling pickled mustard tuber, Yangzhou pickles, Xiaoshan dried radish... I won't say more, I'm drooling.

However, this traditional food has also been questioned by many.

There are many reports that pickles are harmful, and the World Health Organization has even identified them as a possible carcinogen.

The global incidence of gastric cancer according to WHO shows:

The number of gastric cancer patients in China accounts for nearly half of the world's gastric cancer patients, and the incidence of gastric cancer in East Asian countries that love to eat pickled vegetables is quite high.

Do pickled vegetables really cause cancer?

Do pickled vegetables cause cancer? One of the reasons why pickled vegetables have a risk of cancer is that they contain nitrites, which may be converted into carcinogenic nitrosamines in the body.

Nitrite is actually not uncommon in food. It is an important preservative in meat products.

But in pickles, it is produced naturally during the production process:

During the growing process, vegetables absorb nitrogen from the soil and fertilizer to form nitrates.

Nitrates are converted into harmful nitrites under the action of harmful microorganisms.

However, as the pickling and fermentation process proceeds, the harmful microorganisms decrease and the nitrite will be degraded.

If you make pickles at home, the nitrite content tends to rise to a peak and then decrease.

Many cases of poisoning from eating pickled vegetables are caused by eating pickled vegetables when the nitrite content is at its peak.

Even if it is not at its peak, if the nitrite is not reduced to a safe range, eating too much of this pickled vegetable will increase the risk of cancer.

The national standard requirement for nitrite content in pickled vegetables is ≤ 20 mg/kg.

We have seen many netizens start eating pickled vegetables 1 to 2 weeks after they are made.

The question is, how long does it take for the pickled vegetables to drop to a safe level of nitrite?

We did a pickle experiment and here are the results:

Homemade pickled vegetable review: Since there are so many ways to make pickled vegetables, and everyone thinks that their own way is the standard way, we made pickled vegetables three times in two consecutive years.

I made a total of 12 jars of pickled vegetables at the company twice, including spicy kimchi made with chili peppers, ginger, garlic and other ingredients, and pickled sauerkraut with nothing but salt and vegetables.

I also flew to the home of a fan in Northeast China and collected the sauerkraut made by her mother.

Since the preparation of kimchi involves the addition of many ingredients, which increases the uncertainty factor, we will first compare the simplest method that only adds salt.

Nitrite comparison The pickles were sampled every 7 days and sent to the laboratory for testing on the same day.

The nitrite content of pickled vegetables reached 420 mg/kg on the 7th day, 21 times the safety line. By the 28th day, the nitrite level still had not dropped below the safety line.

At the same time, there are still a lot of miscellaneous bacteria - coliform group - after 7 days and 14 days.

Bacteria are the culprit that converts nitrate into nitrite.

The nitrite in the pickled cabbage did not drop below the safety line on the 7th day, but on the 14th day it was only 2.9 mg/kg and was edible. There were no bacteria at all.

For sauerkraut pickled in Northeast China, the nitrite content has not been high since the 7th day, so it can be safely eaten after 7 days.

From the above test results, we can find that the nitrite content of pickled vegetables made from green vegetables is significantly higher than that of pickled vegetables and sauerkraut made from Chinese cabbage, and it takes longer to reach the safety line. Why is this?

We tested the lactic acid bacteria content of these pickles:

The lactic acid bacteria content in pickled cabbage and Northeastern sauerkraut is significantly higher than that in pickled green vegetables.

During the fermentation process, lactic acid bacteria can increase acidity, inhibit the growth of harmful bacteria, and promote the degradation of nitrite, significantly reducing the nitrite content.

Magical Vitamin C While looking up information, we found a practical trick:

Vitamin C can inhibit the formation of nitrite and promote the degradation of nitrite that has already been formed.

We grind and dissolve the vitamin C tablets at a ratio of 0.4 g/kg and add them into the jars containing the vegetables.

(You can use the small white bottle of vitamin C for 3 yuan. You only need to add 4 tablets for 1 kg of vegetables.)

The pickled vegetables that were added with vitamin C at the beginning not only reduced the nitrite content by nearly half at the peak, but the value on the 21st day had already dropped below the safety line.

For pickles without added vitamin C, it took 35 days to drop below the safety line.

It can be seen that pickled vegetables with added vitamin C not only reduce the risk of poisoning, but can also be enjoyed earlier.

In addition, we also tried adding vitamin C during the process and found that the nitrite in the pickled vegetables was also greatly reduced.

If you have already made a few jars at home, you can add some vitamin C to them.

Pickle

We also tested kimchi with added ingredients such as ginger, garlic, chili, pears, apples, etc., and the results were not much different from those of the pickled cabbage mentioned above.

To sum up my two years of making pickled vegetables, I believe that after reading this, many people will still say that this is not how we make pickled vegetables at home.

In fact, we have previously collected methods of pickling vegetables from everyone. Although they are different, they are basically the same.

From the results of our evaluation, the principles are not much different, and the conclusions can be used for reference:

Pickles made from green vegetables will reach the safe range after 35 days, while pickles made from Chinese cabbage can be eaten after 14 days.

Adding vitamin C can quickly reduce nitrite, whether it is added at the beginning or in the middle;

The nitrite content will also be affected by temperature and environmental hygiene. If you are not sure about it, it is recommended to buy packaged pickled vegetables in the supermarket (packaged with detailed production information).

Although pickled vegetables are delicious, it is best to avoid eating them when the nitrite content is highest.

I believe you must have friends and family who love to eat and make pickled vegetables. Forward this article to them and let’s eat pickled vegetables together in a healthy way.

In addition, there are many causes of gastric cancer, not just pickled vegetables, such as Helicobacter pylori, excessive intake of nitrite, etc.

References:

[1] http://gco.iarc.fr/today/
[2]Etemadi A, Safiri S, Sepanlou SG, et al. The global, regional, and national burden of stomach cancer in 195 countries,1990–2017: a systematic analysis for the Global Burden of Disease study 2017[J]. The Lancet Gastroenterology & Hepatology, 2020, 5(1): 42-54.
[3] Pang Yuchen, Li Yuanzhi, Qiao Qian, Chen Pei. Research on methods to reduce nitrite in pickled vegetables [A]. Guangdong Food Society. Proceedings of the "Health and Safety" Academic Seminar and the 2015 Guangdong Food Society Annual Conference [C]. Guangdong Food Society: Guangdong Food Society, 2015: 3.
[4] Li Shuhua, Pu Biao, Chen Fengzheng. Effects of VC and fermentation temperature on nitrite in pickled ginger[J]. China Brewing, 2006(02):34-36.
[5] Fang Yuezhen, Lin Longwu. Nitrite poisoning caused by eating pickles together[J]. Straits Journal of Preventive Medicine, 2004(06):34-35.