Can we eat the wild vegetables picked from the green belts?

The weather has warmed up, the trees have started to sprout, and the grass has started to turn green. Many friends have started to carry small baskets and shovels to dig wild vegetables to taste. In addition, I don’t know if it’s a joke, but a netizen who is in quarantine expressed the following emotion…

Image from Weibo

I understand your desire to eat fresh vegetables, but you can’t just eat wild vegetables. In addition to the possibility of pollution from pesticides, some wild vegetables can be really “deadly”.

01

The wild vegetables you dug may be "poisonous vegetables"

There are certain safety risks behind the craze for wild vegetables, because most people dig wild vegetables in parks, farmlands, hillsides, woods, roadsides, etc. The wild vegetables and their growing environment in these places have not been tested, and may contain excessive amounts of herbicides and pesticide residues.

Domestic garbage, exhaust gas from passing cars, wastewater and exhaust gas from factories, etc. may pollute the soil and wild vegetables themselves, thereby causing excessive amounts of harmful substances in the wild vegetables. If not handled properly, this may endanger your health.

Taking lead as an example, a study tested the lead and cadmium content in 90 wild vegetable samples of water celery, amaranth, shepherd’s purse, and water celery from eight regions in Zhejiang Province. The results showed that the heavy metal lead content of the three wild vegetables exceeded the standard rate by 56.7%, and there were differences in different regions. [1]

If the human body's lead intake exceeds the standard, it will mainly damage the hematopoietic system, nervous system and kidneys, and will cause adverse symptoms such as metallic taste in the mouth, abdominal pain and diarrhea, palpitations and irritability, hyperactivity, inattention, insomnia, fatigue, and memory loss.

Tuchong Creative

In addition to lead, many other toxic substances may also accumulate in wild vegetables. Moreover, in the green areas of some public places, since the plants here are for viewing rather than eating, pesticides and other pesticides may be sprayed more frequently. The pesticide content in wild vegetables dug in such places can be imagined.

In addition, although digging wild vegetables is fun for people, it is not fun for the environment at all, because the small shovels are used to dig them all the way, and people trample on them, which can easily make the vegetation and soil a mess. This practice, if done in the wild, would destroy the local ecological environment, and in the park, it would trample on and destroy the lawn, which is an uncivilized behavior.

Therefore, when we go for an outing in spring, just enjoy it and don’t bring a shovel. If you like to eat wild vegetables, you can choose to buy them in regular supermarkets, which have professional quality control and can eat them with more peace of mind.

02

Don’t touch these two wild “vegetables”:

The above mentioned that all wild vegetables that are picked by yourself and have not been quality controlled may pose health risks when eaten. The following two types are simply poisonous.

1. Wild Celery:

Wild celery | Tuchong Creative

Wild celery is also known as large-leaf celery. In Northeast my country, there are frequent cases of poisoning caused by ingestion of wild celery. The toxic components are coniine, methyl coniine, and conitoxin [2].

After consumption, people will suffer from arrhythmia, nausea, vomiting, blurred vision, numbness of the whole body, and even death. It mainly grows in humid places, its leaves are like celery leaves, it blooms in summer, and the whole plant is poisonous and accompanied by a foul smell.

2. Xanthium sibiricum:

A kind of Xanthium sibiricum | Tuchong Creative

I still remember a news story a few years ago: a parent picked Xanthium sibiricum and boiled it in water to treat his child's rhinitis, which caused poisoning. The child suffered liver damage and was admitted to the ICU for treatment.

Raw Xanthium sibiricum is toxic to a certain extent. Eating it can cause food poisoning and damage the liver, which can be fatal in severe cases. Xanthium sibiricum needs to be processed to reduce its toxicity as a traditional Chinese medicine. [3] In addition, many so-called folk remedies or improperly used medicinal plants can be dangerous, such as the case of poisoning caused by the misuse of Datura. [4] Xanthium sibiricum may be easier to distinguish, but wild celery is often misidentified and people are poisoned every year. Therefore, if we want to eat wild vegetables, we should pay attention to the following points:

If you want to buy it, you should go to the supermarket, which is safe and reliable.

03

What nutrients do the wild vegetables that can be bought have?

With the demand for wild vegetables, it is normal to cultivate and sell them artificially. After all, even when we get lunar soil samples, we have to worry about whether we can grow vegetables first... Here is a brief introduction to the wild vegetables that can be found in supermarkets and their nutritional value.

1. Dandelion:

Everyone is very familiar with the small yellow flowers and hairy balls of dandelions, so here is a picture of it on the cutting board | Tuchong Creative

This is a wild vegetable that everyone is familiar with. It tastes very bitter, and the bitterness mainly comes from choline and bitter substances in it. Studies have shown that dandelion also has certain medicinal value. [5, 6]

From a nutritional point of view, the vitamin C content of fresh dandelion leaves is relatively high, at 47 mg/100 g, which is 1.3 times the vitamin C content of the Chinese cabbage we often eat. Many people eat dandelions raw, which can better preserve the vitamin C. [7]

Dandelion also contains a lot of vitamin B2. The vitamin B2 content of the leaves is 0.39 mg/100 g, and the vitamin B2 content of the flower buds is higher than that of other organs, at 1.57 mg/100 g. It is easy to be deficient in vitamin B2 in our diet, which can cause symptoms such as seborrheic dermatitis, fatigue, angular cheilitis, and conjunctival congestion[8]. Eating 100 g of dandelion leaves can meet 32.5% of an adult woman's daily vitamin B2 requirement.

2. Shepherd’s Purse:

Shepherd's purse | Tuchong Creative

Shepherd's purse is a delicacy that many people like, especially when used to make dumplings with shepherd's purse and pork filling, shepherd's purse wontons, and shepherd's purse and tofu soup, which taste so delicious.

Shepherd's purse is not only delicious, but also nutritious. It contains a lot of vitamin C, mineral calcium and beta-carotene.

The vitamin C content of shepherd's purse is similar to that of dandelion. Eating 200g can meet 86% of the daily vitamin C requirement. Its calcium content is higher than that of milk, 2.7 times that of milk. The beta-carotene content is also good, at 2590 micrograms per 100 grams, nearly three times higher than that of dark vegetables such as pumpkin, which is good for eye health. [7]

However, shepherd's purse has a high oxalic acid content, so it must be blanched before eating. Put it in a pot of boiling water, the water should cover the shepherd's purse, and blanch it for 1 minute.

3. Purslane:

Purslane | Tuchong Creative

Purslane is a common wild vegetable with a unique taste and certain medicinal value.[9]

In terms of nutritional value, purslane's beta-carotene content is relatively outstanding, at 2230 micrograms per 100 grams, and it contains oligosaccharides that can improve intestinal health.

4. Mugwort:

Artemisia | Tuchong Creative

Artemisia argyi, also known as mugwort, is generally used to make green rice balls during the Qingming Festival. It has a special fragrance.

The most prominent nutrients of mugwort are dietary fiber, minerals calcium and potassium. Its dietary fiber content is 3.6g/100g, which is higher than that of the green leafy vegetables we often eat, such as Chinese cabbage, leeks, spinach, and water spinach. It can promote gastrointestinal motility, prevent constipation, and is beneficial to intestinal health. [7]

Its potassium content is 677mg/100g, which is 2.6 times that of bananas, and is relatively friendly to people with high blood pressure. As for its calcium content, although it is also quite high, at 137mg/100g, it also contains tannic acid that affects calcium absorption, so it needs to be blanched in boiling water before eating.

5. Toona sinensis:

Chinese toon | Tuchong Creative

Chinese toon is a favorite of many people. The most common ways to cook it are scrambled eggs with Chinese toon, Chinese toon sprouts with tofu, and cold Chinese toon salad.

Compared with the Chinese cabbage we often eat, its vitamin C, carotene, magnesium, calcium, and iron content are 1.1 times, 8.8 times, 3 times, 1.7 times, and 4.9 times that of Chinese cabbage, respectively. In addition, the dietary fiber content of Chinese toon is twice that of Chinese cabbage, which is very helpful in preventing constipation. [7]

However, the nitrite content of Chinese toon is not low. Studies have shown that the average nitrite content of Chinese toon after washing is 160.55 mg/kg. After being placed for 48 hours and blanched in 100°C boiling water for 30 seconds, the average nitrite content is 14.29 mg/kg. In addition, the nitrite content of Chinese toon stored for different storage times increases with the extension of storage time. The nitrite content of Chinese toon stored for 48 hours is 2.6 times that of that stored for less than 24 hours. [10]

The nitrite content of common Chinese cabbage ranges from 0 to 11 mg/kg[11]. In comparison, the nitrite content of Chinese toon is quite high. Excessive intake of nitrite can bring health risks, so it is recommended to blanch it before eating.

To sum up: although wild vegetables are delicious, it is not civilized to pick them by yourself. On the other hand, you may ingest harmful substances that affect your health and may also be poisoned. If you want to try wild vegetables, you can

Purchase in supermarkets.

Author | Xue Qingxin, member of Chinese Nutrition Society, registered nutrition technician, health manager, public nutritionist

Review | Wang Kang Director of Beijing Botanical Garden Science Center Professor-level Senior Engineer

Editor | Ding Zong

This article is produced by the "Science Rumor Refutation Platform" (ID: Science_Facts). Please indicate the source when reprinting.

The pictures in this article are from the copyright gallery and are not authorized for reproduction.

References:

[1] Shang Suwei, Wu Cuirong, Jiang Buyun, et al. Determination of heavy metal content in three wild vegetables in Zhejiang Province[J]. Jiangsu Agricultural Science, 2014, (4): 266-267.

[2] Li Xianghao, Xue Jing. Analysis of 3 cases of poisoning caused by ingestion of wild celery[J]. Chinese Journal of Practical Internal Medicine, 2007(S2):159-160.

[3] Wang Chu, Ma Qingmei, Chen Zongran. Rescue and nursing of acute Datura poisoning[J]. Chinese Journal of Practical Neurological Diseases, 2012, 15(8):89-91.

[4] Wang Chu, Ma Qingmei, Chen Zongran. Rescue and nursing of acute Datura poisoning[J]. Chinese Journal of Practical Neurological Diseases, 2012, 15(8):89-91.

[5] Zhao Shouxun, Hang Bingqian. Chemical components and pharmacological effects of dandelion[J]. Chinese Wild Plant Resources, 2001, 20(3):1-3.

[6] Chen Dan, Li Zhihong, He Hong. Analysis of nutritional components of various organs of dandelion[J]. Journal of Nutrition (4): 360-362.

[7]. Yang Yuexin. Chinese Food Composition Table 6th Edition Volume 1[M]. Peking University Medical Press, 2018

[8] Yang Yuexin, Ge Keyou. Chinese Nutrition Science Encyclopedia 2nd Edition (Volume 1)[M]. People's Medical Publishing House, 2019

[9] Han Guoping, Duan Yufeng, Yang Dongyan, et al. Pharmacological effects and nutritional health effects of Portulaca oleracea[J]. Northwest Journal of Pharmacy, 2003, 018(002):89-90.

[10]. Zhang Binyan, Wang Yanzeng, Qin Zhiyi. Study on reducing the nitrite content of edible Toona sinensis[J]. Chinese Journal of Preventive Medicine, 1999, 33(004):254.

[11]. Lu Qilin1, Wang Na2, Feng Xuqiao1,2,*, Zhao Hongxia2, Huang Xiaojie2,3. Analysis on the changes of nitrate and nitrite contents in Chinese cabbage during storage[J]. Food Science, doi: 10.7506/spkx1002-6630-201418030.

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