The main reason for kidney calculi is the increase of calcium salt, oxalate and phosphate in human body.
When the concentration of these components in urine becomes high and concentrated, kidney calculi will be formed.
In soybean, the main substances related to stones are oxalic acid, purine and calcium. But in the process of processing, these components will change differently.
Oxalic acid is the most common and main cause in kidney calculi. However, the content of oxalic acid in tofu, especially brine tofu and gypsum tofu, is very low, and the content of oxalic acid in foods further processed from tofu (such as dried tofu) is not high, and even patients with stones can eat it.
After soaking soybeans, most of the purines are removed, and a large amount of water contained in tofu will further dilute the purines. Foods rich in calcium can help reduce the risk of stones. This may be because calcium in food can combine with oxalic acid to prevent excessive oxalic acid from entering blood and urine.
Kidney calculi patients don't have to worry that eating tofu will aggravate their condition. It should be noted that kidney calculi patients should drink more water, eat eggs, meat, milk and other high-quality protein in moderation, and eat less salt and foods rich in oxalic acid, such as spinach, asparagus, peanuts and soybean flour.
As for healthy people, there is no need to worry that eating tofu or bean products will cause kidney calculi.