KidStar BioFe Pure Iron - A gentle chewable iron supplement that will not upset sensitive stomachs or stain teeth like common iron supplements. Many iron supplements irritate the digestive system causing constipation, diarrhea, nausea, and cramping. You don’t have to worry about these side effects with BioFe. Iron is an essential mineral needed for mental, physical and emotional development in children. In both adults and children, iron is an essential component of hemoglobin which transfers oxygen from the lungs to the body’s tissues. Iron also provides us with much-needed energy. Iron is utilized by the brain to make several neurotransmitters including serotonin, our happy hormone, and melatonin, our sleep hormone. Iron is necessary for a healthy immune system.