The mineral iron is important for the transport of oxygen. It is also a component of many enzymes. A deficiency can lead to fatigue, pale skin or anemia. A chronic overdose of iron should be avoided.

Iron: the functions of the trace element

Iron is a component of haemoglobin, which has the important ability to bind oxygen. Haemoglobin, also known as the red blood pigment in erythrocytes (red blood cells), transports oxygen and distributes it throughout the body via the blood.

Likewise, iron is an important component of myoglobin, which stores oxygen in the muscle (myo = muscle).

Enzyme component
Iron is a component of various enzymes. Thus, it has an influence on the energy production in the cells (respiratory chain) or on the degradation of drugs. It is also a component of various antioxidant enzymes.

Recognize iron deficiency symptoms

  • anaemia
  • pale skin, brittle hair, grooves in fingernails
  • rapid fatigue, poor ability to concentrate
  • decreased performance
  • inflammations, susceptibility to infections

Fatigue, difficulty concentrating:
The symptom fatigue is too unspecific and can have different causes. Therefore, additional iron should only be added if the iron status has been determined via a blood test.

The most common cause of anaemia is iron deficiency. The iron deficiency leads to an insufficient transport capacity of oxygen in the blood. Supplementation of iron can counteract this deficiency and thus anemia. The additional administration of vitamin C, B6, B12 and folic acid seems to improve the increase of the iron content in the blood even more.

The areas of application of iron

  • Anemia due to iron deficiency
  • Heavy menstrual bleeding (menorrhagia)
    In women with heavy menstrual bleeding, the losses of iron via the blood are very high. These can hardly be compensated for through the diet, which can lead to a deficiency. Supplementation of iron can compensate for the loss.
    Dosage: 30-60 mg per day
  • Pregnancy & Lactation
    The iron requirement during pregnancy is twice as high as before pregnancy. Iron deficiency can increase the risk of premature birth or low birth weight. If not enough iron can be absorbed through the diet and the iron status is a problem, supplementation is advisable.
    Read the blog article "Nutrition in pregnancy: the most important nutrients for mother and child" to learn more about the most important micronutrients in pregnancy.
  • Vegetarian and vegan
    Due to the poorer availability of trivalent iron from plant sources, care should be taken to ensure that sufficient vitamin C is consumed at the main meals. Whether this is done via food or in the form of a supplement plays a subordinate role. If the iron status is too low, supplementation with a reasonably dosed preparation makes sense (5-15 mg).
  • Patients taking "gastric protectors"
    Long-term use of acid blockers (proton pump inhibitors) can decrease the absorption of micronutrients such as iron.
  • Restless-Legs-Syndrome
    Patients with restless legs syndrome (jittery legs) often have an iron deficiency. Correcting the deficiency with supplements can reduce symptoms.
    Dosage: 30-100 mg iron per day

The absorption of iron in the body

So-called bivalent iron, as found in animal foods (e.g. meat), can be absorbed directly via a transporter (DCT1). Trivalent iron, e.g. from plant foods, must first be converted into bivalent iron in the body. Subsequently, it is also transported to the liver via the blood. Thus, the absorption capacity of trivalent iron is about 10 to 15 % lower than that of bivalent iron.

Vitamin C improves the absorption of iron many times over. Therefore, iron supplements should contain additional vitamin C or be taken together with beverages or foods containing vitamin C. Coffee or black tea, on the other hand, have an inhibitory effect on iron absorption.

The hormone hepcidin is significantly involved in the regulation of iron absorption in the intestine. If high amounts (> 60 mg) of iron are taken in, the hepcidin concentration increases and causes absorption to be reduced. To avoid this effect, it makes sense to take iron in lower doses, but on a long-term basis. This also reduces the known undesirable side effects such as constipation or abdominal pain.

Iron overdoses

Iron is not an unproblematic element. Chronically excessive iron doses can lead to deposits in the body, since iron cannot be excreted. Exceeding the storage capacity can lead to cell damage in the liver, heart and pancreas. In the mitochondria of the cells, the excess iron ions can enter into so-called Fenton reactions. This results in the formation of radicals that can damage DNA.

Iron deficiency makes you pale and flabby - but too much is not desirable either. The iron status can be well estimated by laboratory tests.

Iron in food

100 g contain:

pumpkin seeds     9 mg            lentils, quinoa     8 mg
tofu   5 mg   oatmeal   4 mg
beef   4 mg      


What should you know before taking it?

Iron preparations can discolor the stool black. However, this is not a cause for concern. However, it is important to inform the doctor if you are taking other medications. These can interact with iron and impair its absorption. Medications that neutralize stomach acid (antacids) and certain mineral preparations containing calcium and magnesium, for example, inhibit the absorption of iron into the body. 

Conversely, iron can also weaken the effect of other medicines, such as some antibiotics and thyroid hormones. So talk to your doctor or pharmacist if you are taking any other medicines. He or she will advise you on what to bear in mind for your individual combination.

For example, the following foods can interfere with iron absorption:

  • black and green tea, coffee
  • milk
  • cola drinks and other phosphate-rich foods (for example, processed cheese)
  • Rhubarb, spinach, beet and other foods rich in oxalic acid
  • cereals, rice, soy and other sources of phytic acid

These should therefore never be taken together with iron supplements.

Products with iron...