1. Benefits of spinach to the human body. Spinach contains iron. Eating more spinach can supplement iron. 2. Spinach contains a large amount of dietary fiber. Regular consumption can promote intestinal peristalsis and facilitate defecation. 3. Spinach contains folic acid. , Folic acid has a certain effect on blocking the occurrence of coronary heart disease. The harmful effects of spinach on the human body include: Spinach contains oxalic acid, which will combine with calcium in the human body, leading to the formation of calcium oxalate, which can easily form stones.