PM2.5 is so harmful! Food is not reliable for clearing lungs. Here are 4 things to do

Recently, many places have seen obvious sandstorms. When you open the curtains in the morning, you can see orange outside the window. When you wake up, you feel like you are on Mars. The visibility in most areas is less than 1000m. Some media said that the sandstorm in the north mainly originated from Mongolia.

Sina Weibo

The air environment on Earth is worrying, with haze and sandstorms coming frequently. We all know that PM2.5 is harmful to the body, but how harmful is it? If you want to protect your health, what can you do more reliably?

01

How harmful is PM2.5?

Can cause damage to many body systems[1]

Haze is one of the most common air pollution that can seriously endanger human health. It is caused by many reasons, such as coal burning, automobile exhaust, domestic waste, industrial dust, and emissions of waste industrial raw materials.

Excessive inhalation of PM2.5 will increase the incidence of diseases of the respiratory, cardiovascular, reproductive, and immune systems, as well as the incidence of mental illness.

Data shows:

Living in cities with severe air pollution for a long time, the risk of lung cancer is 10~15% higher than in cities with relatively clean air; smog increases the risk of cancer more than smoking, and also increases the incidence of chronic cough, asthma and bronchitis. A survey on the correlation between PM2.5 and blood pressure in the United States found that for every 10ug/M3 increase in PM2.5 concentration, the average systolic blood pressure of the subjects will increase by 8.6mmHg. Other studies have found that the PM2.5 concentration is proportional to the mortality rate of heart disease patients. If the PM2.5 concentration exceeds 10ug/M3, the mortality rate of heart disease patients will increase by 20%. It seems that the harm of smog days is really not small, and it is not okay to ignore it. In addition to doing a good job of protection, how effective are the "lung cleansing foods" that people pass on by word of mouth? Is it useful for expelling PM2.5?

02

Lung-clearing foods do not exist:

Fungus, pig blood, and pears do not clear the lungs

Whenever there is haze, you will see similar advice: "Eat more black fungus", "Eat more pig blood", "Eat more pears", believing that these foods can clear the lungs and expel PM2.5.

In fact, there is no such thing as "lung-clearing food" in nutrition. Let's talk about these three often mentioned lung-clearing foods one by one.

① Fungus: The reason why fungus is said to “clear the lungs” is that it has an adsorption effect and can absorb PM2.5 and expel it from the body.

In fact, according to the rumor, if you want to absorb PM2.5, you have to give it a chance to meet. But PM2.5 enters the lungs through the respiratory tract, and after we eat wood ear, it first enters the stomach and then enters other parts of the digestive tract. These two substances almost never meet each other, and wood ear has no chance to contact the lungs, so it can't achieve the so-called lung-clearing effect at all.

② Pig blood: The reason why pig blood is said to “clear the lungs” is that the feces will be black after eating pig blood. It is believed that the pig blood brings out PM2.5, so the feces turns black.

In fact, the reason why the feces turn black after eating pig blood is the effect of the mineral iron. The iron content of pig blood is very high, at 8.7mg/100g, which is nearly three times the iron content of lean pork[2]. If you eat clams or beef instead, your feces will also turn black if you eat too much of them. It has nothing to do with PM2.5. The reason is the same as eating black fungus. Pig blood and PM2.5 do not come into contact with each other, and they also cannot have the effect of clearing the lungs.

③ Pear: The reason why pears are said to "clear lungs" is that they can moisten the lungs and relieve coughs, but in fact, there is not enough research to prove that eating pears can moisten the lungs. Many people feel comfortable after eating pears, mostly because the high water content of pears can moisten the throat, so it relieves the symptoms of coughing. In fact, drinking more water will have the same effect, which does not mean that eating pears can clear the lungs.

03

When the air is polluted, it is recommended to do the following:

① Reduce outdoor activities, and it is best not to go out if you can;

② Close the doors and windows at home, don’t turn on the air conditioner, and choose a good air purifier;

③ Wear a mask when traveling. If it is just to prevent smog, a KN90-level mask is enough. However, we cannot slack off in the current epidemic situation. It is recommended to wear a KN95/N95 mask;

④ Balanced diet: It is recommended to give priority to foods rich in high-quality protein, vitamin A, vitamin C, and mineral zinc. Because these foods are very helpful in protecting the respiratory mucosa and improving immunity, such as meat, eggs, dairy products, shellfish, fresh fruits and vegetables, and drink more water.

To summarize:

There is no such thing as "lung-clearing food". The ingredients mentioned in the rumors, such as black fungus, pig blood, and pears, are good for your health if consumed in moderation, but don't expect them to have the effect of clearing the lungs.

In the face of severe air pollution, the most important thing is to take good protection and ensure a proper diet, and exercise properly at home. Treadmills, small dumbbells, yoga, and indoor skipping rope are all good exercises.

References:

[1]. Chai Jing, Peng Cao. Causes of haze formation and its impact on human health[J]. World Latest Medical Information Abstracts, 2017.

[2]. Yang Yuexin. Chinese Food Composition Table 6th Edition Volume 2[M]. Peking University Medical Press, 2018

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

Review | Gao Chao, Associate Researcher, Institute of Nutrition and Health, Chinese Center for Disease Control and Prevention

This article was first published on the Science Refutation Platform