The trace element iron is needed in the body for the creation of haemoglobin and for the transport of oxygen in the blood, for the immune system and for the development of the human body. In addition to animal foods, it can be found in quinoa, oat flakes, sesame seeds, spinach, beans, lentils and pumpkin seeds. The best way to get it is by taking vitamin C at the same time, for example with orange juice.