Popeye loved spinach and i'll tell you why! Not only was he building up strong muscles, he was also protecting himself from osteoporosis, heart disease, colon cancer and arthritis at the same time. Spinach is an excellent source of iron, a mineral that is particularly important for menstruating woman, who are more at risk of iron deficiency. Growing children also have increased needs for iron. Iron is an integral component of haemoglobin, which transports oxygen from the lungs to all body cells, and is also part of key enzyme systems for energy production and metabolism.