Iron Absorption

The reason why iron is given an added importance in the functioning of the human body is because of its integral part in the respiratory system. It is an important component of the hemoglobin which plays an essential role in the transport system of the blood flow and fulfills the function of conveying the essential oxygen throughout the body. This makes absorption of iron a critical operation.

Iron and Hemoglobin

Hemoglobin is found in the red blood cells of most vertebrates. It is also found in some of the invertebrates. Hemoglobin is a metalloprotein, that helps the circulation of oxygen throughout the body. Hemoglobin is basically made up of proteins and heme, which is basically made up of iron. The conveyance of oxygen and nutrients is done with the help of red blood cells. The red blood cells contains about 97% of the dry blood cell content, which is of course quite substantial. 1.36 and 1.37 ml O₂ per gram of hemoglobin, can bind oxygen to be carried to the different organs. In short, the prescribed amount of iron is an absolute necessity to keep the supply of oxygen constant throughout the body. The shortage of supply of iron is known as anemia, where the red blood cells in the human body tend to shrink and often their number becomes sparse. Iron deficiency can also lead to anemia and some other growth related conditions. As a conclusion, one might say that iron is an indispensable constituent of the human body.

Process of Iron Absorption

Absorption of iron in the human body takes place through the digestive tract, most importantly the small intestine. The remaining organs of the digestive system always contribute their bit to breaking down of food matter. However, the important part comes when the iron from the food source gets assimilated into the blood flow and into the hemoglobin. This process is aptly termed as the 'absorption' of iron. This process of absorption is initiated by a class of cells that is termed as enterocytes. These cells are present in the inner glycocalyx surface of the duodenum, of the small intestine. The glycocalyx, is an extracellular polymeric surface that is secreted by the cells themselves.

It must be noted that iron that is a part of protein is usually absorbed by the body. This 'absorbable' iron containing protein is often referred to as the heme protein. The ferrous form of this protein is chemically represented as Fe²⁺. Not all dietary irons are in this form, and some of them have to be reduced down from Fe³⁺. This function is conducted at the 'brush border', where a ferric reductase enzyme (a type of enzyme), duodenal cytochrome B, reduce it down to Fe²⁺. The process of conversion finishes here and a protein by the name DMT1, which is also known as divalent metal transporter 1, transports the iron into the cell. There are some very complex procedures that are involved in later stages where the iron optimizes the oxygen carrying capacity of the hemoglobin. Rare absorption problems might arise in this procedure, which can prove to be very dangerous if left undetected, but can be cured.

Iron being an important nutrient, is included in many diets and is prescribed by many health departments and agencies. Red meat and poultry products are considered as important sources of iron. Leafy vegetables and fruits are also important sources of iron.