Spinach is a vegetable, which originated in Persia more than 2000 years ago, so it is called? Spinach? Just a homonym. This dish was loved by the people of China when it was introduced to China from Nepal in the Tang Dynasty. How can this dish easily lead to kidney calculi?
What the hell is going on here?
It turns out that spinach is rich in oxalic acid, while tofu is rich in calcium. Oxalic acid and calcium are easy to combine and precipitate into calcium oxalate, which is easy to form stones in human kidneys.
Then, let Tadpole Jun comb it for you.
What is oxalic acid?
Oxalic acid, also known as oxalic acid, is an organic acid synthesized by itself in spinach. Although oxalic acid is weaker than sulfuric acid, sulfuric acid is an inorganic acid, while oxalic acid is a strong acid in organic acids, and its acidity is 10000 times that of acetic acid. Oxalic acid itself can be dissolved in our digestive juice and blood, but it can easily combine with some mineral elements such as calcium to form insoluble oxalate.
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Chemical molecular structural formula of oxalic acid
The content of oxalic acid in 100g spinach is 606mg, which is very high.
Two human physiological systems related to oxalic acid metabolism
After oxalic acid enters the human body, it generally passes through the digestive system and then enters the circulatory system. The digestive system includes esophagus, stomach and intestine, while the circulatory system includes lymph and blood. Oxalic acid has certain influence on both systems.
Can spinach tofu soup eat? The role of oxalic acid in digestive system
Oxalic acid in spinach will combine with calcium in tofu to form calcium oxalate, which will become a precipitate insoluble in digestive juice. When we eat spinach tofu soup, we will eat this kind of sediment. This sediment can't be decomposed by digestive juice in our digestive tract, so it will be excreted directly, just like a person who eats a grain of sand will be excreted through stool. So the consequence is that our bodies don't absorb the calcium in tofu. But this is not a great pity, because we eat tofu mainly to eat protein in tofu, even if we can't eat calcium in tofu. Therefore, spinach tofu soup can still be eaten. Of course, when cooking this dish, the oxalic acid in spinach may be much more than the calcium in tofu, which means that the oxalic acid in the whole soup is excessive and needs to be careful.
What happens when oxalic acid enters the blood circulation system?
Oxalic acid first enters the digestive tract of human body, and then enters the blood through the digestive tract such as stomach and small intestine, which will combine with calcium in the blood and cause functional hypocalcemia spasm in severe cases. Moreover, calcium oxalate formed in blood will precipitate and gather in the kidney or bladder of human body, causing kidney calculi or bladder stones. In view of this risk, we need to be careful not to let excessive oxalic acid enter human blood.
How to reduce oxalic acid in cooking process
Since the oxalic acid content in spinach is so high, can't we be provoked and hide?
Blanching spinach can reduce the oxalic acid content in spinach by 50%, which is a very effective method. Therefore, when making a spinach tofu soup, you should first blanch the spinach, and then pour out the blanched water, so that you can make a spinach tofu soup.
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Author: Tadpole Jun