What is iron?

Iron is an essential trace element that plays a central role in oxygen transport, energy metabolism, the immune system, and cell formation. It is a component of the red blood pigment hemoglobin, which picks up oxygen from the lungs in red blood cells and transports it to the body's cells. Without iron, cells could not receive enough oxygen - energy production would break down.

About two-thirds of the body's iron is found in hemoglobin, with 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 store it only to a limited extent, which is why a continuous supply through the diet is necessary.

There are two forms of iron in food:

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

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

How does iron work?

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

Oxygen transport and energy production:
The most important function of iron is 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 cells.

Blood formation:
Iron is indispensable for the formation of new red blood cells. If iron intake is insufficient, the body cannot produce enough hemoglobin - resulting in iron-deficiency anemia, which can manifest 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 defense against pathogens. A deficiency can weaken immune function, while balanced iron levels strengthen the body's defenses.

Brain and nervous system:
Iron plays an important role in the formation of neurotransmitters such as dopamine, serotonin, and noradrenaline. As a result, it influences mood, concentration, memory, and mental 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.

Benefits 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 absorption in the intestines. Symptoms include exhaustion, paleness, brittle nails, hair loss, dizziness, and concentration problems.

Iron excess:
Excessive intake - especially from high-dose supplements - can cause nausea, stomach discomfort, 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 taken not together with coffee, tea, milk, or calcium, as these substances inhibit absorption.

Conclusion

Iron is an indispensable trace element for energy, blood, the immune system, and the brain. It ensures that every cell receives an adequate supply of oxygen - the basis for vitality, concentration, and performance. Women, athletes, vegetarians, and vegans in particular have increased requirements. A balanced diet or targeted supplementation - ideally in a well-tolerated form such as iron bisglycinate or iron(II) gluconate - helps maintain iron levels within the optimal range and provide the 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.