Iron and its functions in the body
The essential trace element iron is a vital mineral that must always be present in your body. Numerous functions of the body, including the important oxygen supply of the cells, depend on iron. Since the body cannot produce iron itself, you have to take it in with your food.
In our body there are only minimal amounts of the important trace element, about 60 mg per kg body weight. According to the definition, trace elements are contained in the organism with up to 50 mg per kg body weight, but medically iron is assigned to the trace elements because of its mode of action.
Iron metabolism
Iron metabolism is the term used to describe the absorption, distribution and excretion of iron in the organism. The term metabolism is somewhat misleading because the iron itself is not metabolised, but binds to the various molecules. In our body there are about 2500 to 5000 mg of iron, also called body iron, less in women than in men. The body strives for a balance between absorption, storage, use, recycling and loss of body iron and thus tries to keep the iron content in the body constant. Read more about determining iron levels in the blood.
About 80 % of iron is present in biologically active compounds called functional iron. Most of it is bound in the red blood pigment, haemoglobin, about 10% in myoglobin, a protein in muscle tissue, and 3% in enzymes involved in metabolism. The life span of a red blood cell is about 120 days, after which it is broken down in the spleen and liver. The iron released in this process is available to the body again, it is recycled to form new blood cells.
20 % of the iron is found as a non-biologically active reserve in the liver, spleen, intestinal mucosa and bone marrow; this iron is also called storage iron. Unused iron is stored there and made available when there is too little iron. Less than 1 percent of the iron circulates in the blood bound to transferrin.
Here is iron involved....
Transport and storage of oxygen
Iron is the basic building block of the protein complex haemoglobin, which binds oxygen in the red blood cells and gives them their red colour. An important task of iron is the binding and transport of oxygen: iron-containing haemoglobin takes up the oxygen in the lungs and distributes it to all cells. No other element in the human body can perform this task. The protein myoglobin stores and transports oxygen within the heart and skeletal muscle cells.
Iron is also very important for energy metabolism: in addition to transporting and storing oxygen, iron is directly involved in the formation of adenosine triphosphate ATP. In the mitochondria, which are also called the power plant of the cell, ATP is produced in the presence of oxygen via the respiratory chain. The oxygen is transported by the iron-containing haemoglobin to wherever it is needed. ATP is the most important energy carrier of the metabolism; it is involved in almost all metabolic reactions and supplies the necessary energy.
Iron is an important component of the enzyme thyroid peroxidase (TPO); an iron deficiency can promote or exacerbate hypothyroidism. A large proportion of hypothyroid patients are iron deficient.
Iron is necessary for the formation and breakdown of numerous hormones, so that the iron levels in the blood should always be checked in the case of hormonal disorders.
Iron is a component of the cytochrome P450 enzymes, these are an important component for detoxification reactions in the liver. There, substances that are difficult to dissolve in water and cannot be excreted are changed in a two-stage process so that they can be excreted via the kidneys or the bile in combination with the body's own substances. For the first process, the phase I reaction, the iron-containing CYP enzymes are necessary. Iron is thus of central importance for the degradation of drugs and harmful substances.
Iron supports the normal function of the immune system. It is needed for the formation and release of oxygen radicals, which are necessary for the intracellular digestion of pathogens. Beware of bacterial infections: here iron therapy can serve as a growth factor for the bacteria!
Collagens are found in the skin, connective tissue, bones and cartilage. Their function is to give shape and tension to cells and tissues. The stability of collagens is strongly influenced by propyl hydroxylase, an iron-containing enzyme. Thus, an iron deficiency can lead to structural defects of the collagens, which is visible in increased wrinkling of the skin.
Optimal iron status in the body
There are few nutrients where the range between too much and too little is as narrow as with iron. If you take too little iron over a long period of time, you risk an iron deficiency; if you take too much iron over a long period of time, especially through iron supplementation, you risk an iron surplus in the body. Within limits, our body is able to regulate the iron content in the blood through the absorption rate. With an adequate supply, the rate is about 10 %; with empty iron stores, it can rise to 30 %; in pregnant women, values as high as 60 % have even been measured [1]. However, if the iron intake is too high, the regulating intestinal cells are damaged, so that large amounts of iron enter the blood uncontrollably and accumulate in the liver, pancreas and heart and can lead to secondary diseases. Healthy people can achieve an optimal iron supply with a balanced diet.
Conclusion
Iron is vital for our body and must be ingested in sufficient quantities with food. Our body contains 2.5 to 5 grams of iron, most of which is bound to the red blood pigment haemoglobin. About one fifth of the iron is largely stored in the spleen and liver and is available to the body if not enough iron is taken in. Many functions of the body depend on iron.
