Regulating iron balance

REGULATING IRON BALANCE

Iron metabolism is one of the most heavily regulated processes in the body. This is due to the body excreting very little iron. Hepcidin, a hormone produced in the liver, plays a crucial role in iron regulation. It inhibits iron absorption, promotes the excretion of iron from the cells and reduces the bioavailability of iron when the reserves are at capacity. On the other hand, chronic inflammation may increase hepcidin levels, which in turn may lead to iron deficiency and anemia. Excessive iron in the body can be poisonous. It leads to the production of free oxygen radicals and causes oxidative stress and cellular damage. Conversely, if the body's iron reserves are low (for example, due to iron deficiency anemia), very little hepcidin is secreted. The body constantly strives for equilibrium or homeostasis.

Cellular iron levels are regulated by so-called iron-responsive elements (IREs). These are short nucleotide sequences that are found in protein-coding messenger RNA molecules. IREs control iron regulatory proteins (IRPs) that regulate iron storage, transportation, and use. One example is the regulation of ferritin, the main iron storage protein. Conversely, transferrin receptor-1 regulates cellular iron uptake. Both of these can be measured using laboratory tests.
Inflammation and infection often increase the volume of iron in the body due to most pathogens requiring iron to multiply. On the other hand, the immune system also needs plenty of iron to create an effective immune reaction to fight a pathogen. This may mean the production of lymphocytes and reactive oxygen radicals.

The average amount of iron in the human body is 2.3 g for women and 3.8 g for men. The body excretes very little iron. Women lose iron, particularly during their menstrual period which may cause anemia and mild symptoms of iron deficiency if the flow is heavy.