This leafy green vegetable is known to be super-nutritious when it comes to nutrients and is loaded with minerals & vitamins. However, most of these nutrients are not absorbed completely when uncooked. It is packed with oxalic acid that blocks the absorption of iron & calcium. When it is cooked, it releases the bound calcium that makes it more available for the body to absorb. Also, when spinach is steamed, it reduces the risk of certain cancers.