The calcium in spinach can help strengthen your bones to fight against injury, and vitamins A and C, fiber, folic acid, and other nutrients fight against colon and breast cancers. Spinach also helps to lower damaging protein levels in the blood and can protect against high blood pressure and heart disease. A thin, flexible stem indicates a tender, young plant. Choose these spinach leaves for salads or recipes where the spinach is served raw. ... Spinach stems, even of some young leaves, are fibrous, stringy, and difficult to eat, especially after cooking. An important green leafy vegetable and medicinal herb. Spinach in an annual herb belongs to the family Chenopodiaceae. It is native to SouthWest Asia and widely distributed and cultivated through the world including Iran as vegetables for its high nutritious value.