What is iron?

Iron is a vital trace element that plays a central role in oxygen transport, energy metabolism, the immune system, and cell formation . It is a component of hemoglobin , the red blood pigment that carries oxygen from the lungs to the body's cells. Without iron, cells could not be adequately supplied with oxygen, and energy production would collapse.

Approximately two-thirds of the body's iron is found in hemoglobin, the remainder in muscles (as myoglobin ) and enzymes involved in energy and cellular processes. The body contains a total of around 3–5 grams of iron and can only store it to a limited extent, which is why a continuous supply through diet is necessary.

There are two forms of iron in food:

  • Heme iron (from animal sources such as meat, fish, poultry) is particularly well absorbed.

  • Non-heme iron (from plant sources such as legumes, whole grains, nuts, spinach) is absorbed less efficiently, but its absorption can be significantly improved by vitamin C.

How does iron work?

Iron is involved in a variety of essential processes that keep the body and mind functioning.

Oxygen transport and energy production:
Iron's most important function lies in the transport and storage of oxygen . Hemoglobin in the blood and myoglobin in the muscles require iron to bind oxygen. At the cellular level, iron is a component of numerous enzymes that produce energy (ATP) in the mitochondria – the "powerhouses" of the cells.

Blood formation:
Iron is essential for the formation of new red blood cells. Insufficient iron intake means the body cannot produce enough hemoglobin, resulting in iron deficiency anemia , which manifests as fatigue, paleness, shortness of breath, and reduced performance.

Immune system:
Iron supports the activity of immune cells (especially lymphocytes and macrophages) and contributes to the defense against pathogens. A deficiency can weaken immune function, while a balanced iron status strengthens the body's defenses.

Brain and nervous system:
Iron plays a crucial role in the production of neurotransmitters such as dopamine, serotonin, and norepinephrine. This influences mood, concentration, memory, and cognitive performance. Adequate iron intake is particularly important for brain development during childhood.

Hormones and metabolism:
Iron is a component of enzymes involved in the synthesis of hormones, DNA, and collagen . It also contributes to detoxification in the liver.

Advantages of iron

  • Enables oxygen transport in the blood

  • Supports energy production and reduces fatigue

  • Promotes the formation of red blood cells and hemoglobin

  • Supports concentration, memory and mental performance

  • Strengthens the immune system

  • Contributes to hormone and DNA synthesis

  • Supports skin, hair and nails through improved cell regeneration.

Possible side effects and interactions

Iron is essential, but balance is crucial: both deficiency and excess can cause health problems.

Iron deficiency:
The most common nutrient deficiency worldwide. Causes include blood loss (e.g., menstruation, surgery), an unbalanced diet, or impaired intestinal absorption. Symptoms include fatigue, paleness, brittle nails, hair loss, dizziness, and difficulty concentrating.

Iron surplus:
Excessive intake – especially through high-dose supplements – can lead to nausea, stomach upset, or constipation. Chronically elevated iron stores (e.g., in hemochromatosis ) can damage the liver, heart, and pancreas.

To improve absorption, iron should ideally be combined with vitamin C and not taken with coffee, tea, milk or calcium , as these substances inhibit absorption.

Conclusion

Iron is an essential trace element for energy, blood, the immune system, and brain function. It ensures that every cell is adequately supplied with oxygen – the foundation for vitality, concentration, and performance. Women, athletes, vegetarians, and vegans, in particular, have an increased need for iron. A balanced diet or targeted supplementation – ideally in a well-tolerated form such as iron bisglycinate or iron(II) gluconate – helps maintain optimal iron levels and provides both body and mind with renewed energy.

Sources

  1. Abbaspour N, Hurrell R, Kelishadi R. (2014): Review on iron and its importance for human health. J Res Med Sci , 19(2), 164–174.

  2. Ganz T, Nemeth E. (2012): Iron metabolism: interactions with normal and disordered erythropoiesis. Cold Spring Harb Perspect Med , 2(5), a011668.

  3. Beard JL, Connor JR. (2003): Iron status and neural functioning. Annu Rev Nutr , 23, 41–58.

  4. Zimmermann MB, Hurrell RF. (2007): Nutritional iron deficiency. Lancet , 370(9586), 511–520.