Ferritin is a protein inside your blood cells that stores iron so your body can use it later. The amount of ferritin in your blood is directly related to the amount of iron stored in your body. Iron is an important mineral that carries oxygen throughout your body.
Ferritin Function
Ferritin controls the level of iron in your body and helps prevent iron deficiency by releasing iron into the blood when levels are low and by storing excess iron when levels are high. Ferritin's structure is important to its ability to release iron in a controlled manner. It is a hollow, sphere-shaped molecule. Inside, iron is incorporated in the mineral ferrihydrite, which is connected to the inner wall. When iron is needed, it is excreted through channels in the sphere.
Importance of Iron
Iron is part of hemoglobin, the oxygen-carrying part of red blood cells. With the help of iron, red blood cells carry oxygen to all parts of your body. It also aids in immune function, cognitive development, metabolism and temperature regulation. About 90 percent of the iron in your body is conserved for daily use, and the remainder is excreted. Men are able to store more iron than women, primarily because women lose iron during their menstrual cycles.
Iron Transport
Once ferritin releases iron into the blood, it is transported by a protein called transferrin. Each transferrin molecule has two iron ions. The protein locks iron in place due to its arrangement of amino acids that form four bonds to the iron ion. Once it locates iron atoms, transferrin flows through the blood until it locates a transferrin receptor on the surface of a cell. Once found, it binds tightly and is drawn into the cell; when inside, it releases iron.
Deficiency and Testing
If your doctor suspects that you have an iron deficiency, he will perform a ferritin test to measure the amount of ferritin in your blood. This can indirectly measure the amount of iron stored in your body. According to the Mayo Clinic, if your ferritin levels are low, it indicates you may have iron deficiency. If your ferritin levels are abnormally high, it could indicate an inflammatory condition, liver disease or another underlying condition.
References
- Washington University Department of Chemistry; Iron Use and Storage in the Body: Ferritin and Molecular Representations; Rachel Casiday, Regina Frey; November 2000
- The Ohio State University Extension FactSheet; Iron; Kate Micucci; December 2004
- RCSB Protein Data Bank; Ferritin and Transferrin; David Goodsell; November 2002
- MayoClinic.com; Ferritin Test; February 2011
