Spinach and tofu are a perfect match for calcium supplementation and bone strengthening. Spinach and tofu cannot be eaten together - after decades of publicity, this sentence has become a household rule and is deeply rooted in the hearts of the people. However, according to the research results in recent years, it can be determined that spinach and tofu are not only a good match, but also a perfect match for calcium and bone strengthening. In the past, it was believed that spinach should not be eaten with tofu. There was only one reason: spinach contains a large amount of oxalic acid, which will combine with calcium to form an insoluble precipitate. However, this statement fails to see another aspect of the problem - spinach also contains a variety of factors that promote calcium utilization and reduce calcium excretion, including rich potassium and magnesium, as well as vitamin K. Everyone knows that calcium is closely related to acid-base balance. When protein foods are taken in too much, the acid-base balance is imbalanced, and the body's calcium excretion will increase. At this time, if you can eat more green leafy vegetables, such as spinach, you can fully absorb potassium and magnesium, help maintain acid-base balance, and reduce the amount of calcium excretion, which is very beneficial to bone health. 100 grams of spinach contains 311 mg of potassium and 58 mg of magnesium, ranking first among vegetables, 2.7 times the potassium content of Fuji apples and 11.6 times the magnesium content. With the rich potassium and magnesium in spinach, the calcium in tofu can be better retained in the human body. What’s more worth mentioning is that the vitamin K in spinach has the powerful effect of promoting bone calcium formation. Vitamin K is one of the hot topics in nutrition research in recent years. It is an essential component for the formation of "osteocalcin". Vitamin K is mainly found in green leafy vegetables and vegetable oils, and spinach is one of the vegetables with the highest content, second only to kale, with a content of 415 micrograms/100 grams. Survey data shows that the daily intake of vitamin K for middle-aged and elderly women is more than 109 micrograms, and the risk of fractures can be reduced by 30%. There are also studies that prove that supplementing 200 micrograms of vitamin K every day can maintain and improve bone density. In other words, you only need to eat less than 100 grams of spinach every day to achieve this effect. Studies have shown that if vitamin K is added while supplementing calcium, the effect of calcium supplementation can be greatly improved and calcium deposition into bones can be promoted. Tofu, which is rich in calcium and protein, and spinach, which is rich in potassium, magnesium and vitamin K, are the perfect combination to supplement calcium and strengthen bones. So, what to do with the oxalic acid in spinach? Since oxalic acid is very soluble in water, more than 80% of the oxalic acid can be removed by simply blanching the spinach in boiling water for 1 minute and taking it out. Fry the tofu first, then add the blanched spinach, and it will be fine if you mix them together. Fortunately, vitamin K is not sensitive to heat and is not soluble in water, so blanching spinach will not cause its loss. However, vitamin K, like carotene, requires oil to help absorb, so when making spinach tofu soup, be sure to add some oil.