“Iron Man & Woman” — For hundreds of years the importance of dietary iron was common knowledge. Despite this understanding, one of the most common worldwide nutrient deficiencies is iron. This is also the only nutrient where the RDA for men is less than the RDA for young women. (3)
Every living cell contains iron, amounting to approximately 5 grams, or one teaspoon for the whole body. Iron absorption is based on a number of factors. This article provides an overview of what factors come into play in its absorption. (2)
Absorption – Controls
Once iron is absorbed it is not easily eliminated from our bodies, therefore, it is important to control iron absorption. Several mechanisms exist to regulate our body’s ability to absorb iron. Generally, iron absorption depends on:
- the body’s need for iron,
- its form in a particular food,
- and many other factors.
Healthy people absorb approximately eighteen percent of the iron present in food, however people who are iron deficient absorb more. (2)
Absorption – Form Counts
Iron is found in different forms based on the food. The amount absorbed is influenced by the particular form. Within animal flesh, approximately forty percent of the total iron is:
- hemoglobin, the form that is found in red blood cells, and
- myoglobin, the pigment that is present in muscle cells.
This kind of iron is referred to as heme iron and is absorbed approximately 2 – 3 times better than nonheme iron (the simple elemental iron). Nonheme iron is the form that is added during the enrichment process to grain products. It is also found in:
- animal flesh,
- milk,
- eggs,
- grains,
- vegetables, as well as
- other plant foods. (2) (3)
Citrus Fruit – Increases Absorption of Nonheme Iron
Consuming nonheme iron with heme iron together increases the absorption of nonheme iron. Consuming more vitamin C rich foods will increase iron absorption, especially if blood iron is too low or there is inadequate dietary iron. Copper also aids with the body’s iron use.
Iron is the oldest known trace mineral critical for the growth and development of the human body. A number of factors influence its absorption, including its form (whether heme or nonheme) as well as other foods with which it is consumed. The body of knowledge is vast and this article just touches upon its absorption. The next article will further delve into what affects its absorption and its distribution.
References:
https://www.cdc.gov/immpact/micronutrients/index.html
https://www.cdc.gov/nutritionreport/99-02/pdf/nr_ch3.pdf
https://www.cdc.gov/mmwr/preview/mmwrhtml/00051880.htm