However, spinach contains a lot of oxalic acid. Oxalic acid combines with calcium in the body and becomes calcium oxalate. This may be the reason of kidney calculi. So don't cook spinach with tofu.
Although oxalic acid is harmful, it is only a matter of intake. As long as you don't eat much, you don't have to worry. When spinach is heated, oxalic acid will disappear. If some animals, protein and oxalic acid are added, the harm will be minimized. If you add some dried seafood when cooking spinach, you can eat it safely. As long as it is eaten in moderation, spinach is not only harmless, but also healthy.
Spinach contains a lot of oxalic acid. When oxalic acid meets calcium and zinc in human body, it will produce calcium oxalate and zinc oxalate, which is not easy to be absorbed and excreted. Children need a lot of calcium and zinc for their growth and development. If the body lacks calcium and zinc, it will not only lead to bone and tooth dysplasia, but also affect intellectual development.