The micronutrient Iron is an important mineral that the body uses for a number of processes such as neurological (brain and nervous system) development, energy production, physical growth etc. Iron is required to make the proteins hemoglobin and myoglobin. Hemoglobin as a protein found in red blood cells that is responsible for the transport of oxygen from the lungs to the tissues in the body. Myoglobin is a protein that transports oxygen to the muscles. Therefore, iron supports muscle metabolism through its involvement in the synthesis of myoglobin.
Iron is also an essential component of the enzymes that constitute the electron transport chain in the mitochondria. The mitochondria is an organelle present in all of our cells (except RBCs) that produces energy for the body via the electron transport chain in a process known as oxidative phosphorylation. The electron transport chain consists of a series of enzymes that transfer electrons which creates an electrochemical gradient that is used to drive the generation of the energy molecule known as ATP. Iron is present in some of the enzymes in what is known as iron-sulfur clusters and plays a major role in the transfer of the electrons. Thus, iron is also important for energy production.
Sources
There are two forms of iron. There is non-heme iron found in plant sources like spinach, nuts, beans, fortified grains etc. The other form is heme which is present exclusively in animal products such as meat, seafood etc. Heme iron is more bioavailable than non-heme iron. This means that the body will absorb heme iron much better compared to non-heme. Pairing foods that have both heme and non-heme iron will help to increase the bioavailability of the non-heme form. If you are vegetarian another way to increase your iron absorption is to pair your non heme iron sources with foods high in vitamin C as vitamin C enhances iron absorption. Examples of vitamin C rich foods include citrus, tomatoes, sweet peppers etc. On the flip side calcium interacts with iron by inhibiting its absorption so consuming iron with calcium rich foods might reduce its absorption.
Recommended Dietary Allowance for Iron
9-13yrs 8mg
14-18yrs: Female- 14mg, Male-11mg
19-50yrs: Female- 18mg, Male-8mg
over 51 yrs: 8mg
Intake, Status and Deficiency
Most people get enough iron in their diets. However girls and women on child bearing age are at risk of developing iron deficiency due to blood loss from monthly menstruation. Pregnant woman are also at risk because their red blood cells expand to meet the needs of the fetus and thus require an increase in iron intake to match this demand, otherwise, their stores will be depleted which could result in mortality of both mom and fetus. Food insecurity can also increase risk of iron deficiency. Iron deficiency occurs in stages. The first stage is a mild deficiency when the body turns to the iron stores when dietary intake is low.
These stores include the spleen, bone marrow, liver etc. Once these stores get depleted this is considered an intermediate or marginal deficiency. The third stage is when the body develops iron deficiency anemia. Check out this previous blogpost on anemia for more information.
Symptoms of iron deficiency include lethargy, inability to regulate body temperature (that's why people with low iron tend to be cold most of the time), impaired immune function, weakness etc. Iron status is typically assessed by a complete blood count test. The doctor hemoglobin levels, blood iron levels and serum ferritin levels(reflects the size of your iron stores). Your iron stores is the amount of iron that your body has outside of dietary intake (includes, bone marrow, spleen, liver and muscles).
As always, be careful when deciding to take iron supplements. Confirm that you have a deficiency before including iron supplements as unnecessary supplementation which will lead to overconsumption of iron can have negative impacts such as GI issue, constipation etc. If you do need to take iron supplements, make sure to stay hydrated and include fiber and movement to prevent potential risk of constipation.
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