Various "lung clearing foods" are widely spread in the society, For example, a microblog wrote: "Continuous haze weather damages the lungs. In addition to reducing travel and wearing masks, proper diet can also achieve the effect of clearing the lungs. White radish can cure phlegm and cough, Sydney stewed lily, tremella and lotus seed soup can moisten the lungs and resist viruses, Luohanguo tea can clear the lungs and reduce fire, and Auricularia auricula, grapes and purple cabbage can nourish yin and moisten the lungs. Duck blood and pig blood are especially recommended. The effect of clearing the lungs is the best! It is said that workers in the mine must eat fresh duck blood every day after work." Are these foods really effective?
Can food affect inhaled particles
The haze that damages the lungs is full of fine particles. Generally speaking, PM10 refers to particles with a particle size of less than 10 microns in the air. Such particles can enter the lungs through the respiratory system, so they are called "inhalable particles". If the particle size is less than 2.5 microns, it can further reach the bronchioles of the lung and deposit there. These particles affect the gas exchange in the lungs, leading to various respiratory symptoms and even lung cancer. Among them, those with particle size less than 0.1 micron can further pass through the alveoli and enter the blood, which can lead to vascular sclerosis and harm the cardiovascular system.
To "remove" particles inhaled into the lungs, you have to let the "cleaner" meet them. Comparing the movement of air particles and food in the body, we will find that food has no chance to meet those particles with a particle size greater than 0.1 micron, so it is naturally impossible to "remove" them. The extremely "small" particles that enter the blood are still huge in front of the small molecules of food. Although the possibility of "mice beating elephants" cannot be ruled out logically, there is no experimental evidence. Therefore, relying on these foods to remove dust is just a beautiful imagination.
Where did the legend of "lung clearing food" come from
The "basis" of some food "clearing the lung" is that the stool turns black after eating, which seems to excrete pollutants in the air. Similarly, there are various "detoxification" foods or health care products, which are considered to "work" because they cause black stool.
The color of stool is really related to food. Clinically, some speculation can also be made through the color and texture of stool. However, black stool does not turn black due to absorption of air pollutants. One of the most common causes is gastrointestinal bleeding, especially peptic ulcer or cancer. Usually, such black will be sticky and smelly.
In addition, some foods, dietary supplements or drugs can also cause black stool. The most common case is iron. For example, taking iron supplements usually leads to black stool. The content of iron in animal blood products is high. If you eat too much, you may also produce black stool. However, they have nothing to do with "clearing the lung".
Some people explain that food "clearing the lung" is that food contains so and so components, which have a certain effect on the human body, so this kind of food can ensure the "discharge of toxic and harmful substances" and "increase immunity", so as to resist the "harm" of air pollution. This big and empty reason has no value. Every nutrient needed by the human body has such a role. For example, if you don't drink water or eat, people will get sick or even die. Naturally, you can't resist the "dust hazard". According to this way of reasoning, we can draw the conclusion that "both water and rice can clear the lung".
In addition to animal blood products, there are many "lung clearing" foods in traditional medicine, such as pear, rock sugar, tremella, radish and so on. Some people say that these so-called "lung clearing foods" clear the "lungs in traditional medicine", which can alleviate the symptoms related to the respiratory tract, such as cough, phlegm and so on. However, it should be noted that when the ancients put forward the concept of "clearing the lung" and issued a "lung clearing recipe" or "lung clearing prescription", they probably didn't realize the matter of air pollution. Whether these foods can alleviate those respiratory symptoms remains to be seen, but the concept of "clearing the lung" is completely different from that of "clearing the lung" to solve air pollution.
So "food clearing lung" is just a good wish. Any kind of food cannot remove or reduce the impact of dust pollutants in the air on the lungs. "Lung clearing food" and "lung clearing health care products" are just gimmicks.