Li Ziqi's allergy caused her face to ulcerate and swell. The allergens are in the foods you love to eat.

Recently, Li Ziqi has returned to the public eye. The lacquerware making video she released showed people the beauty of lacquerware. However, in the process of learning to make lacquerware, Li Ziqi and her team had severe allergies. Li Ziqi was allergic to the point that her whole body was red and swollen, and her face was wrapped in gauze.

Li Ziqi posted a picture of her allergy

The main raw material for lacquerware production is raw lacquer, which is taken from the lacquer tree. It contains an allergen that causes allergies in most people - urushiol, which is also the reason why Li Ziqi's team is allergic. What many people don't know is that urushiol is commonly found in plants of the Anacardiaceae family, but the content varies.

When it comes to "Anacardiaceae", you may feel unfamiliar, but in fact, many foods we often eat are members of the Anacardiaceae, such as mangoes, cashews, pistachios, etc., and they also contain different amounts of urushiol.

Urushiol, the culprit of allergies

Urushiol is a general name for a class of substances, accounting for 40% to 80% of the total mass of raw lacquer, including saturated urushiol, monoene urushiol, diene urushiol and triene urushiol.

The final paint film formed by raw lacquer is the result of these phenols working together. This process is almost the same as the process of artificially producing plastics today. However, artificial production of plastics requires the addition of catalysts, while raw lacquer has its own catalyst, which is laccase.

In the lacquer tree and just after being harvested, urushiol will not be polymerized into plastic, because laccase is wrapped by some special proteins (glycoproteins) and will not come into contact with urushiol. Glycoproteins will form soap bubble-like structures in urushiol, and laccase and water will be wrapped in them. When the raw lacquer is applied to the target surface, these "soap bubbles" burst, and the urushiol, driven by laccase, pulls together and becomes a natural plastic - paint film.

Of course, urushiol is not prepared for us to paint furniture, it is the weapon of urushiol trees against animals. After urushiol enters our skin through contact, it will bind to the cell membrane and become a special antigen. At this time, the immune system will respond, and those cells bound to urushiol will become invaders to be removed, so redness, swelling and itching will follow. If anti-allergic treatment is not carried out, this battle will continue.

Lacquer tree that has been cut down丨Image copyrighted by the library, reprinting and using may cause copyright disputes

There was a report that a child developed an allergic reaction after playing with raw lacquer. His parents took him for simple anti-allergic treatment, and the symptoms were temporarily relieved. However, a month later, gangrene appeared on the child's fingers, so his parents took him to see a doctor. Fortunately, the child's hand was saved.

To this day, raw lacquer is still an important chemical raw material needed in our production and life. Through molecular modification, we have produced relatively safe lacquer phenol formal, lacquer phenol epoxy resin and other excellent materials.

Common Anacardiaceae Foods

Anacardiaceae is a large family, and many Anacardiaceae plants contain urushiol, including some foods we eat every day. Of course, the urushiol content in these foods is either very low or can be reduced to a very low level through some methods, which allows us to enjoy the deliciousness of these foods. Below, we will introduce some common Anacardiaceae foods.

1

mango

Mango is a member of the genus Mangifera in the Anacardiaceae family. According to the Flora of China, there are about 50 species of Mangifera in the world, and 5 species are distributed in my country.

Although mangoes are juicy and delicious and are loved by many people, for a small number of people, eating mangoes is not a pleasant thing. Some people will have itchy skin when they come into contact with mango juice. In severe cases, their mouths will swell into "sausage mouths", commonly known as "mango mouths". A very small number of people may also have systemic allergic reactions.

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The reason why mangoes can cause allergies is because they contain urushiol. However, the content of urushiol is not particularly high, so most people will have no problem eating mangoes, but people who are particularly prone to allergies should be a little careful when eating mangoes.

2

cashew

Cashews, although they look completely different from mangoes, are actually from the same family as the soft and sweet mango. This plant of the Anacardiaceae family is native to the rainforests of northeastern Brazil. They were already a delicacy for the locals before the arrival of Portuguese explorers in the 16th century.

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Cashew shells contain "cashew nut shell oil", which contains some chemicals represented by cardanol, which can corrode human skin. This is also a common feature of the Anacardiaceae plants where cashews are found. Therefore, the cashews we can buy are generally processed cashew kernels or cashews with skin, but not cashews with shells.

3

pistachio

Pistachio is a plant of the genus Pistacia in the Anacardiaceae family. Like cashews and mangoes, it is a member of the Anacardiaceae family. It is worth noting that if you search in the Flora of China, you will not find the name pistachio at all. The correct name of this plant is actually "A Yue Pistachio". This Persian name points out its origin. The origin of pistachio is in Central Asia and the Middle East, and the country with the largest production is Iran.

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Human consumption of pistachios is very old. Current archaeological evidence shows that the history of human consumption of pistachios can be traced back to 6750 BC. In the Bronze Age (3300-1200 BC), residents of Central Asia (today's Uzbekistan) had already begun to cultivate pistachios.

Pistachio kernels also contain very small amounts of urushiol. If you are allergic to mangoes, you may also want to be a little careful when eating pistachios.

In addition to the common fruits and dried fruits mentioned above, the southern sour jujube and betel nut, which are more common in the south, are also members of the Anacardiaceae family and contain a small amount of urushiol. They may also cause some minor troubles for a small number of people. However, for most people, there is no need to worry too much about these foods. For a very small number of people who are very prone to allergies, if they experience discomfort, stop eating immediately and take appropriate anti-allergic treatments, and they will generally return to normal soon.

Planning and production

Author: Shi Jun, science writer and PhD in botany

Review丨Wang Kang, Director of the Science Museum of the National Botanical Garden

Nie Shunli, attending physician of the Department of Rheumatology and Immunology