In fact, it is not accurate to say "blanching to remove oxalic acid". Oxalic acid is very stable and will not decompose when heated. Blanching only makes a part of oxalic acid in spinach run away, and the lost part melts in water (soup). Therefore, if spinach is not boiled and soup is directly cooked, even soup and vegetables are killed, then the total intake of oxalic acid does not decrease, but soldiers enter the human body in two ways.
For people with normal digestive ability and good health, the absorption rate of oxalic acid in the intestine is not high, and a small amount of oxalic acid has little effect after being absorbed. Even the human body itself produces a small amount of oxalic acid in metabolism. Therefore, in the case of adequate calcium intake, it doesn't matter if spinach is not scalded and cooked directly. As long as you drink more water, dilute the concentration of oxalic acid in blood and avoid the abnormal increase of urinary calcium concentration, you can prevent the occurrence of urinary calculi.
However, patients with urinary calculi and digestive tract diseases have higher absorption efficiency of oxalic acid than ordinary people. For the elderly, children, pregnant women, nursing mothers and other people who have a large demand for calcium but do not supplement calcium, excessive intake of oxalic acid will also lead to a decline in the utilization rate of food calcium. The above six groups of people should be cooked before eating spinach.
In fact, the oxalic acid content of spinach varies greatly with varieties, cultivation methods and cultivation time. Spinach in winter is often low in oxalic acid content and astringent, and it is not uncomfortable if it is not cooked. Spinach in summer has more oxalic acid, so it is more astringent. Western countries often mix salad with raw spinach leaves, and there is nothing wrong with it.