Spinach has what is known as “incomplete protein†which simply means that the protein it has does not contain all of the nine essential amino acids which are found in the complete version of protein. Amino acids are what make up protein and there are 20 of them altogether. Nine of the 20 amino acids are essential for complete protein.
You will find that the protein that is found in most plants and vegetables is incomplete, including with spinach. Because spinach contains so many different nutrients as well as vitamins and minerals, it should definitely be added to your daily diet due to all of the nutritional benefits there are to eating it regularly.