Iron is one of the oldest and most well-known micronutrients. It is the key element in the metabolism of almost every living organism on the planet. It is an antioxidant that has many vital functions in the body, including oxygen transport and storage, electron transport, energy metabolism, acting as an antioxidant, as well as DNA synthesis. There are three levels of iron deficiency: storage iron depletion, early functional iron deficiency, and iron deficiency anemia. Symptoms of iron deficiency are the result of associated anemia and can include fatigue, rapid heart rate, rapid breathing, and palpitations. Taking excess iron supplements may cause gastrointestinal irritation, vomiting, diarrhea, constipation, or nausea. Stools can also appear darker than usual. The RDA for Iron is 0.27mg/day for 0-6 months infants, 11 mg/day for 7-12 months infants, 7 mg/day for 1-3 years children, 8 mg / day for 4-8 years children, 10 mg/ day for 9-13 years children, 11 mg/ day for 14-18 years adolescents, 8 mg/day for adult men and 18 mg/day for adult women. Pregnant and breastfeeding women should have 27 mg/day.