Low serum levels of vitamin K in people with osteoporosis cause a dramatic decrease in bone and serum osteocalcin levels, which do not maintain the normal rate of bone mineralization. Vitamin K is an element in the formation of osteocalcin, which is necessary for the deposition of calcium into the bones. Studies have shown that if vitamin K is added to calcium supplementation, the effect of calcium supplementation can be greatly enhanced to promote the deposition of calcium into the bones. Survey data show that the risk of fracture is reduced by 30% in middle-aged and older women who consume more than 109 micrograms of vitamin K per day. It has also been shown that a daily supplement of 200 micrograms of vitamin K has the effect of maintaining and improving bone density. Patients with osteoporosis can eat spinach regularly, 100 g/day. Spinach is very high in vitamin K. The vitamin K in spinach has a powerful effect in promoting bone calcium formation. Spinach is also rich in potassium and magnesium, which help maintain acid-base balance and reduce the amount of calcium excreted, which is also very beneficial for bone health. Tofu, rich in calcium and protein, + spinach, rich in vitamin K, potassium and magnesium, is a good combination. But spinach contains high levels of oxalic acid, which can combine with calcium to form insoluble precipitates that interfere with absorption. So what to do? Since oxalic acid is extremely soluble in water, simply blanch the spinach in boiling water for 1 minute and fish it out to remove more than 80% of the oxalic acid. Stir-fry tofu first, then put blanched spinach, mix together and eat without problems. Vitamin K is not afraid of heat and does not dissolve in water, so blanching spinach will not cause it to be lost. However, vitamin K needs fats to help absorb it, so always remember to put some oil when making spinach and tofu soup.