It is rumored that spinach cannot be eaten with tofu. If you eat too much, you will get stones and affect calcium absorption. The theoretical basis is: tofu + spinach = a lot of oxalic acid = stones. This "theory" seems pretty reliable, so many people don't dare to eat it like this. On the other hand, there is a saying that you should eat more spinach, spinach can supplement iron, the first choice for iron supplement is spinach.
Is spinach a delicacy for iron supplements or the culprit for stones? To eat or not to eat? How should I eat it?
⊙Spinach tofu soup-nothing wrong
Spinach is rich in oxalic acid, and tofu is rich in calcium. The combination of oxalic acid and calcium will produce calcium oxalate precipitation, so eating spinach tofu is easy to form stones in the body. The first half of this sentence is correct, but the following conclusion is wrong.
The oxalic acid in spinach is indeed related to the formation of stones, but the formation of stones is not simply the addition of spinach and tofu, otherwise the human body may be full of stones. The key to the formation of stones depends on whether the "raw materials" are sufficient and the proportions are appropriate. Oxalic acid in spinach will be greatly reduced during the cooking and heating process, so don't worry too much about the formation of stones. Scientific experiments have shown that spinach can be blanched in boiling water for 60 seconds to remove 80% of oxalic acid.
Soybeans are also foods with a relatively high oxalic acid content, but when making tofu and other soy products, there is not much oxalic acid left. Tofu is made by adding magnesium chloride (brine) or calcium sulfate (gypsum). This process not only reduces oxalic acid, but also greatly increases the calcium and magnesium content. Studies have shown that magnesium is very beneficial to the prevention of kidney stones; calcium in food is also a substance that helps prevent stones. Because studies have found that calcium in food (referring to calcium in natural foods, not calcium supplements such as calcium tablets) can be combined with oxalic acid, thereby reducing the body's absorption of oxalic acid and playing a role in preventing kidney stones.
A lot of scientific evidence shows that "spinach cannot be served with tofu" is a great misconception.
The iron supplement effect of spinach is not good, because the iron contained in spinach is non-heme iron, and the body's absorption and utilization of this iron is very low.
The iron in the diet is divided into heme iron and non-heme iron. Heme iron is easily absorbed by the human body and mainly exists in animal red meat and liver blood; plant foods and iron in beans, cereals, and eggs , Which is generally non-heme iron, which is not easily absorbed by the body.
Tips: The absorption rate of iron in plant foods is low
In contrast, if the absorption rate of heme iron in animal foods is 10 points, the absorption rate of iron in plant foods is less than 1 point. Only a few tenths of a cent, a difference of more than ten times.
The absorption rate of iron in spinach is theoretically lower than the absorption rate of non-heme iron in other plant foods, because oxalic acid and other substances will affect the absorption of iron, and the iron content of spinach is not high in vegetables. . Therefore, the effect of iron supplementation in spinach is not good, and it does not make much sense.
Dietary advice
Spinach should be blanched before eating
When cooking spinach, you should first blanch it in water so that you don't have to worry about oxalic acid. Pregnant women do not need to talk about spinach discoloration, because spinach contains folic acid in addition to oxalic acid, which is an essential nutrient for fetal development.
As a kind of vegetable, people don't have to avoid eating spinach, whether with tofu or other foods. Although the iron supplement effect of spinach is far from people's imagination, it is rich in vitamin C, which promotes the absorption of iron.
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