Family members, this kind of food may really cause cancer, I really advise you to eat less

Pickled beans, pickled cucumbers, crispy radishes, pickled radish strips, pickled peppers, pickled mustard tubers... pickled vegetables are an indispensable companion to rice on the table and are favored by many families. Even if there is no cooking, a bottle of pickled vegetables can easily finish 2 bowls of rice, which can be called a magical tool for rice!

However, it is recommended to eat less pickled vegetables, as they are really harmful to your health and may even cause cancer in severe cases.

What are the dangers of eating pickled vegetables frequently?

1

Increased risk of cancer

A study of 440,000 people by the Biosystems Engineering and Food Science Research Team of Zhejiang University showed that regular consumption of pickled vegetables may increase the risk of death from hemorrhagic stroke and esophageal cancer. Regular consumption refers to consumption frequency ≥ 4 days/week. [1] Another meta-analysis of cohort studies showed that an increase of 40g/d in pickled vegetable intake was associated with a 15% increased risk of gastric cancer. [2]

Why does eating pickled vegetables frequently increase the risk of cancer? Most studies believe that it is related to the high salt concentration and nitrite in pickled vegetables. Frequent consumption of high-salt foods can damage the gastric mucosa and esophageal mucosa and induce cancer; and nitrite can react with amines, the decomposition product of protein in the stomach, to form N-nitroso compounds such as nitrosamines, which are extremely teratogenic and carcinogenic.

It should be emphasized here that eating pickled vegetables frequently will increase the risk of esophageal cancer and gastric cancer, but eating pickled vegetables does not necessarily cause cancer. We should be especially wary of short-term pickled vegetables.

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2

Increased risk of high blood pressure

The salt content of traditional pickled vegetables is mostly higher than 15%, and even the salt content of commercial pickled vegetables is not low. For example, the pickled beans in the picture below have 8 grams of salt in 100 grams. Even if you only eat 2 spoons (about 20 grams) per meal, you will consume nearly 2 grams of salt. If you can't help but eat more, the total salt intake for the whole day will easily exceed the standard (no more than 5 grams/day).

A long-term high-salt diet is not conducive to blood pressure control and will increase the risk of hypertension, which will also increase the risk of hemorrhagic stroke.

▲Photo: A certain brand of sour beans

3

May gain weight

Common pickled vegetables include salted vegetables, sour pickled vegetables and candied vegetables. The sugar content of candied vegetables is not low, generally reaching 60%~65%. [4] They are high in carbohydrates and calories, and eating too much will increase the risk of weight gain.

4

Poisoning may occur

If a large amount of short-term pickled vegetables is consumed in a short period of time, nitrite poisoning may occur, inducing toxic methemoglobinemia, with symptoms such as chest tightness, dyspnea, dizziness, headache, shortness of breath, nausea, vomiting and diarrhea. In severe cases, coma, convulsions, incontinence and even death from respiratory failure may occur. [4]

Why can’t you stop eating pickled vegetables?

At this point, some people may say that although eating too much pickled vegetables is unhealthy, pickled vegetables have a crisp texture and unique flavor, so you can't stop eating them. Why are pickled vegetables so delicious?

The answer lies in its fermentation process. The flavor substances of various raw materials and the flavor substances produced after fermentation form the unique flavor of pickles that make people unable to stop.

1

Microbial fermentation

The process of pickling vegetables is accompanied by the fermentation of many microorganisms, such as lactic acid fermentation, alcoholic fermentation, and acetic acid fermentation. The metabolites they produce give the pickled vegetables a unique flavor that is slightly sour, sweet, mellow and delicious. [5]

The final products of lactic acid fermentation include a small amount of ethanol, formic acid, acetic acid, succinic acid, higher alcohols, carbon dioxide, ammonia, etc., in addition to lactic acid. These products give pickled vegetables a refreshing taste and ethanol aroma. The acetic acid in pickled vegetables can also react with ethanol to form ethyl acetate, which adds to the aromatic smell. [5]

In addition, organic acids produced by microbial metabolism are the main flavor substances in pickles.

2

Protein breakdown

The small amount of protein in vegetables will be broken down into amino acids by microorganisms. Currently, more than 30 kinds of amino acids have been found in pickled vegetables. For example, alanine has a pleasant aroma, and aspartic acid and glutamic acid have umami taste. Glycine, serine, and cysteine ​​have sweet tastes. In particular, aspartic acid and glutamic acid will combine with sodium ions in pickled vegetables, making the pickled vegetables taste more delicious. [5, 6]

3

Carbohydrate breakdown

The carbohydrates in pickled vegetables will eventually be broken down into free sugars. As microorganisms multiply, the free sugars will be broken down into volatile flavor substances such as alcohols, acids, and esters. [6]

4

Get flavor from ingredients

Onions and garlic are also added during the pickling process. During the pickling process, onions and garlic will also produce flavor substances such as sulfur compounds, which increase the aroma and taste of the pickled vegetables.

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Pay attention to these 4 points when eating pickled vegetables healthily

The adverse health effects of pickled vegetables are mainly reflected in the high salt, high sugar and nitrite problems. If these problems can be solved and the amount of consumption can be scientifically controlled, there is no need to demonize them.

1

Control the amount of salt

The Chinese Dietary Guidelines recommend that the daily salt intake per person should not exceed 5 grams, but most Chinese residents' daily salt intake far exceeds this standard, and some even exceed it by more than 2 times. If you indulge in pickled vegetables every day, your salt intake will exceed the standard even more.

If you like to eat pickled vegetables, you must reduce the amount of salt you use. For example, if you eat 20 grams of the spicy radish strips shown below, you will consume 1.5 grams of salt more. Therefore, it is recommended to add 3 pinches less salt when cooking throughout the day. It would be better if you can rinse the pickled vegetables with water before eating.

▲Photo: A certain brand of pickled radish strips

1 small pinch weighs about 0.5 grams (female finger), Image source: provided by the author

2

Pickled vegetables instead of salt for cooking

You can directly use your favorite pickled vegetables to cook without adding salt, such as stir-fried mustard greens with meat, stir-fried bitter melon with dried pickled vegetables, stir-fried pickled mustard greens with shredded pork, etc.

Also, don't eat it every day. Limit the frequency of consumption and eat it occasionally, such as 1 to 2 times a week.

3

Pair with fruits and vegetables rich in vitamin C

Vitamin C in fresh fruits and vegetables is a strong antioxidant that can inhibit the production of nitrite in pickled vegetables. It undergoes a redox reaction with the nitrite in the pickled vegetables and has a scavenging effect on nitrite. [7]

When eating pickled vegetables, pairing them with fruits and vegetables rich in vitamin C can improve food safety and reduce the harm of nitrite to the body, such as sweet peppers, broccoli, Chinese cabbage, bitter melon, winter dates, kiwis, strawberries, etc.

4

Buy low-salt pickles

As the concept of health becomes more popular, many low-salt pickled vegetables have appeared on the market, usually with "reduced salt" or "light salt" marked on the packaging. Compared with ordinary pickled vegetables, low-salt pickled vegetables are healthier, and the salt content is mostly below 6%.

▲Photo: a certain brand of pickled mustard tuber

In short, pickles are crisp and delicious, but don't eat too much! If you really like to eat them, it's better to buy low-salt pickles from regular manufacturers, occasionally satisfy your cravings, and eat them scientifically and healthily.

References

[1] Zhuang, Pan et al. “Preserved vegetable consumption and its association with mortality among 440,415 people in the China Kadoorie Biobank.” BMC medicine vol. 21,1 135. 5 Apr. 2023, doi:10.1186/s12916-023-02829-3

[2] Yoo JY, Cho HJ, Moon S, Choi J, Lee S, Ahn C, et al. Pickled vegetable and salted fish intake and the risk of gastric cancer: two prospective cohort studies and a meta-analysis. Cancers. 2020;12(4):996. https://doi.org/10.3390/cancers12040996.

[3] Jakszyn P, Gonzalez CA. Nitrosamine and related food intake and gastric and oesophageal cancer risk: a systematic review of the epidemiological evidence. World J Gastroenterol. 2006;12(27):4296–303. https://doi.org/10.3748/wjg.v12.i27.4296.

[4] Sun Changhao. Nutrition and Food Hygiene 7th Edition[M]. People's Medical Publishing House. 2017:45

[5] Wu Huachang, Zhang Weina, Deng Jing, You Yaohui, Jin Xiaoli. Research progress on flavor substances in pickled vegetables[J]. Chinese Condiments, 2010, 35(11): 26-29

[6] Li Tong, Wu Rina, Zhang Qisheng, Wang Fangfang, Liu Chunli, Ding Ruixue, Yan Danli, Wu Junrui. Research progress on microorganisms in pickled vegetables and their relationship with product flavor quality[J]. Science and Technology of Food Industry, 2022, 43(14): 475-483

[7] Liu Wendan, He Ping, Chen Yunxiang, He Qiongfang, Yang Yanping, Ji Shoulian. Effect of vitamin C on nitrite in commercially available pickled vegetables[J]. Journal of Dali University: Comprehensive Edition, 2015, 14(10): 68-70

[8] Chen Yifan, Li Huanhuan, Zhang Jin, Tang Honggang, Guo Sitong, Zhou Anyuan, Chen Guangyao, Chen Lihong. Research progress on nitrite control in pickled vegetables[J]. Journal of Zhejiang Agricultural Sciences, 2020, 61(12): 2618-2621

[9] Zheng Lianqiang, Yuan Xianling, Luo Yi. Natural preservation technology and application prospects of pickled vegetables[J]. Chinese Condiments, 2021, 46(4): 187-192

Planning and production

Author: Xue Qingxin, one of the first nutrition instructors of the National Health Commission, and a registered nutritionist in China

Review | Ruan Guangfeng, Deputy Director of Kexin Food and Health Information Exchange Center

Planning丨Lin Lin

Editor: He Tong

Proofread by Xu Lailinlin