Spinach contains vitamin K, which has anticancer properties. It has beta carotene, an antioxidant that also protects the eyes and prevents cancer. Spinach is high in iron which is excellent for the hemoglobin in the blood and to prevent anemia. It is high in calcium, which is excellent for the bones. Spinach has a high amount of fiber and a high water content. It is an excellent and healthy food to choose in one's diet.
There are many of these that are generally found in spinach. For example, spinach has a great deal of Vitamin A. It also has Vitamin C, Vitamin E and Vitamin K. It also contains such nutrients as folate and manganese.
Here is a link with much more detailed information.
Though the spinach is renowned for it's iron amount,it is also contains a large amount of active substances, like mineral salts, vitamins, lipids, fibers, also oxalic acid.
The mineral salts that could be found in spinach are: calcium, magnesium,sodium, potassium, iron, zinc, sulfur, manganese, phosphorus, iodine.
The vitamins that could be found in spinach are: Vitamins A, C and E, also the range of B vitamins (B1, B2, B6), folica acid and K vitamin.
The amino acids found in spinach are: arginine and lysine.