Iron and Ferritin
Iron is needed to make red blood cells to carry oxygen to all of our tissues. New red blood cells are made every 3 months, so we need to have sufficient iron to make new red blood cells.
Iron can be difficult to measure because it is stored in the liver and carried around on proteins, so we look at different measurements to assess proper levels.
Ferritin is the cellular storage molecule for iron. Some of the iron we get from food is used right away and some is stored for the times when you don't get enough from the food you eat. If the stores drop too low, the body can't make the red blood cells it needs and we can develop anemia. The most common cause of anemia is low iron levels.
Ferritin - an indicator of iron
A ferritin test helps know how much iron is available to use in the body. Iron is needed to make red blood cells, so when ferritin levels are low, the body makes fewer red blood cells.
Ferritin levels can be high with some medical conditions that have nothing to do with iron levels. It raises when there is significant stress on the body, like in an acute or chronic infection or condition, but only if the iron stores are sufficient.
Laboratory "normal" values of ferritin are currently under reconsideration. Evidence supports levels over 50, not the levels reported as normal ranges.
If the ferritin is low, with or without anemia (low hemoglobin or hematocrit), we recommend iron supplements and then will recheck ferritin along with other iron levels to make sure the level is improving but not going too high.
Iron
Iron is a mineral found in plants and animals and all living things. It's an important component of hemoglobin, the part of red blood cells that carries oxygen from the lungs to the body. Iron gives hemoglobin the strength to carry oxygen in the blood, so oxygen gets to where it needs to go. Without enough iron, the body can't make hemoglobin and makes fewer red blood cells. This means tissues and organs won't get the oxygen they need.
People can get iron by eating foods like meat and dark green leafy vegetables. Iron is also added to some foods, such as infant formula and cereals.
Iron is stored in the liver and measurements are difficult. We use the ferritin described above to estimate the usable iron.
Symptoms of iron deficiency include:
Alopecia (hair loss)
Decreased exercise performance
Fatigue
Impaired cognition
Impaired thyroid function
Increased bruising
Increased susceptibility to acute mountain sickness
Pica (eating non-food items)
Pruritus (itching)
Restless legs (especially at bedtime)
See also our Iron Supplementation page.
