Chicken skin, pig skin, fish skin, what happens when you eat it often? Eating right is a treasure, eating wrong is recuperating

Charred and crispy fried pork skin, fatty roasted chicken skin, crispy and delicious cold fish skin...

There are many delicacies made of "animal skins" in life. Some people think that this is the savior of taste buds, while others think that it is picked up from the garbage heap. Is eating meat better than eating skin?

So are these skins nutritious? Beneficial or Harmful? Today, Uncle will study with you.

In people's impressions, pigskin and cowhide have always been the golden signs of collagen, and many people will boil it into colloid for anti-aging, but is this really the case?

First of all, we can be sure that the protein content of livestock skin is indeed high, and collagen accounts for the majority .

But that doesn't mean that you can replenish collagen by eating these peels .

Collagen is a type of protein. After eating, it is mainly digested by the stomach and small intestine. Under the action of various proteases, it is first decomposed into polypeptides and then hydrolyzed into amino acids . Most of these amino acids will directly enter the blood to participate in the formation of human tissues, and only a small amount can be reconstituted into collagen, which has little anti-aging effect on skin tightening and anti-wrinkle .

The root cause of skin aging is the aging of fibroblasts that synthesize collagen, which greatly reduces the efficiency of collagen synthesis. Therefore, this is not essentially a problem of insufficient raw materials (collagen), but that the working cells are unable to dry, and no matter how much you eat, it will not help.

Peking duck, Cantonese roast goose, Guiyang roast chicken skin... all rely on the crispy and delicious skin to conquer people's tongues. Taking chicken skin as an example, the chief physician of the Affiliated Hospital of Capital Medical University said: chicken skin is rich in fat, high in triglyceride and cholesterol, and frequent consumption of large amounts will increase the incidence of cardiovascular and cerebrovascular diseases, and may also lead to fatty liver.

Especially for barbecue, high-fat chicken skin is more likely to produce the first-level carcinogen "benzopyrene" . If it is burnt, the content of "benzopyrene" is 10-20 times higher than that of ordinary food.

Again, talking about toxicity aside from the dose is a hooligan. Although eating barbecue frequently ≠ 100% cancer, the toxicity of "benzopyrene" can accumulate and lie dormant for 20-25 years . Uncle advises you not to take the challenge lightly. .

In addition, the Beijing Sanitation and Epidemic Prevention Station has done a sampling test and found that the content of benzopyrene in some roast ducks is 0.16-1.30 μg/kg. If the food source is improper, it may exceed the national standard of 5μg/kg after eating 4 meals.

Compared with dirty chicken, duck, beef and sheep, the fish and shrimp swimming in the water not only look natural and healthy, but also the fish skin and shrimp skin are prepared with different flavors: cold fish skin, fried fish skin, shrimp skin soup, shrimp skin pot ... The fat content of fish skin is extremely low, the ratio of amino acids and fatty acids is balanced, and long-term soaking in Haihe River also makes it contain a variety of minerals. In this way, the nutrition of fish skin is indeed much better than that of chicken skin and pig skin, but if you use the wrong cooking method, it will be in vain, especially fried fish skin!

A domestic laboratory has done research on the loss of nutrition from fish skin, and found that the heat denaturation temperature of sea bass skin is 30 °C, tuna skin is 29.7 °C, and salmon skin is 18.6 °C. That is, when the thermal denaturation temperature is exceeded, the collagen on the fish skin will be decomposed and destroyed, and the protein will be lost. After the fish skin is fried at high temperature, not only is there little nutrition left , but the oil intake also soars, which is very unhealthy for the human body.

The "shrimp skin" on the market does not refer to the shell of the shrimp, but is made of dried shrimp, a kind of Chinese seafood, also called dried shrimp. Most of it is usually only used as a seasoning, but in fact, its nutritional content is also very rich. Although the calcium content of dried shrimp is top-notch, when you actually eat it, you will know that 2-3g of dried shrimp is already a lot, but the calcium content here is only 0.02-0.03g. Moreover, gastric acid can only dissolve a small part of the shrimp skin, and most of the calcium in the shrimp skin will eventually be discharged together with the food residues, basically how it comes in and comes out . It is undeniable that all kinds of skins are an indispensable part of Chinese delicacies. You can eat a little when you are thirsty, but if you want to have both deliciousness and health, it is very important to do the following three points: especially for people with obesity and high blood fat. In other words, if you eat too much pork skin and chicken skin, it is very unfavorable for the body's blood lipids and weight control. Try to avoid frying and other methods. It is recommended to choose steaming, cold salad, boiling soup, and stir-frying. Take fish as an example: In general, the bigger and older the fish, the higher the toxin content in the body.

Some studies have found that the mercury content in crucian carp tissue: fish brain > fish skin > fish meat > fish roe. The older the fish, the more mercury accumulates in the fish tissue. Fortunately, the mercury content in each kilogram of fish skin is only tens of micrograms, which is far lower than the limit standard of 0.5mg/kg for methylmercury in aquatic animals and their products. Therefore, when we make selections, the same species of fish give priority to juveniles and small fish.

If you have a friend who is addicted to eating skins, please forward the article to him for the sake of his/her health!

References:

[1]Calleja-Agius， J. and M. Brincat， The effect of menopause on the skin and other connective tissues. Gynecol Endocrinol， 2012. 28(4)： p. 273-7.

[2] Bi Kehai, Zhang Yuying, Sun Yufeng, Zhang Yuqing, Yang Qing, Yu Changhai. The formation conditions and regulation of benzopyrene in fried meat products [J]. Food Industry, 2020, 41(12): 201- 205.

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

[4] Ye Xiaoyan, Zeng Shaokui. Analysis of nutrient components of tilapia skin and discussion on extraction technology of fish skin gelatin [J] Nanfang Aquatic Products, 2008, 5(4).

[5] Li Kaixiong, Zhao Zhiyuan, Liu Xia. Extraction of collagen from pig skin and its application [J]. Meat Research, 1996(4): 43-48.

[6] Yang Maungduan, Du Xueqin. Investigation report on the content of 3.4-benzopyrene in Beijing roast duck [R] Beijing Health and Epidemic Prevention Station.

[7] U.S. Department of Agriculture Food Data Center (USDA)

[8] How to judge the age of a fish? [N] China Science and Technology Museum. 2021.11.09