Iron deficiency in the body – which foods contain it?

Iron is one of the key trace elements. It participates in many processes occurring in the human body. Essential for both blood formation and the functioning of various enzymes and metabolic processes, it is one of the requirements for proper body development. What is worth knowing about iron in the body? What are its daily norms, and what are the risks of a potential excess or deficiency of this element in our diet?

Iron in the body – what role does it play?

Iron is classified as a trace element, a substance essential for our life. Due to the structure of iron, it must be supplied through diet or supplements, as our body is not able to produce iron on its own.

This element is found in the body in the form of the characteristic red blood pigment (haemoglobin), muscle proteins and numerous enzymes. In red blood cells, iron transports oxygen and also plays a role in energy production and proper DNA synthesis.

The element is primarily involved in processes in which oxygen plays a major role:

• It is essential for the oxidation process – it is responsible for energy production in cells and promotes cellular respiration;

• It stores oxygen in the muscles – myoglobin, the red pigment in muscles, is directly related to the action of haemoglobin, ensuring the proper transport of oxygen in the blood to the cells;

• Helps fight infections – the health-promoting effect of iron is also related to its immunostimulatory functions, preventing the development of dangerous infections;

• Reduces signs of fatigue – enables more oxygen to reach the brain, improving alertness and well-being;

• Contributes to healthy skin and hair – meeting your daily requirement ensures strong nails, beautiful hair and healthy-looking skin.

Iron supplementation – when is it helpful?

Probably the best-known method of ensuring an adequate supply of iron in the diet is iron supplements. Available in tablet or capsule form, it is one of the easiest ways to supplement this element. Iron supplementation is recommended for women of childbearing age and people diagnosed with iron deficiency, characterised by anaemia, for example.

Iron supplements are usually taken for two to three months. It should be noted that iron-based supplements may cause stool discolouration, which is a harmless phenomenon indicating the effectiveness of the supplements.

Furthermore, iron-based preparations are particularly recommended for vegans and vegetarians. Many iron supplements are now also available in vegan versions that do not contain animal gelatine.

Haem and non-haem iron – where is it found?

Haem iron is found in significant amounts in animal products such as meat and fish. Animal foods contain bivalent haem iron, which the body utilises better than plant iron, known as trivalent non-haem iron. However, plant-based foods such as legumes, whole grains, spinach, peas and beans also help to meet the daily iron requirement.

Sources of iron – which natural products contain the highest amounts of iron?

• Pumpkin seeds – 10 mg/100 g

• Liver – 7 mg/100 g

• Tofu – 6 mg/100 g

• Soybeans – 4.5 mg/100 g

• White beans – 4.1 mg/100 g

• Roast beef – 4 mg/100 g

• Mussels – 3 mg/100 g

• Sardines – 3 mg/100 g

• Tomatoes – 2 mg/100 g

• Potatoes with skin – 1.7 mg/100 g

Iron absorption and iron assimilation

It is worth mentioning that a mixed diet – simultaneous consumption of animal and plant products – supports the proper absorption of iron from plant-based foods. On the other hand, certain medicines and foods, such as those containing calcium, oxalic acid or polyphenols, inhibit the proper absorption of iron in the body. Daily iron intake standards – what is the correct iron level?

Adequate iron intake is particularly important during childhood and adolescence. A potential deficiency can have a negative impact on growth and brain development.

The body's daily iron requirement (iron level) – depending on age:

• From 1 to 6 years of age – 8 mg per day

• From 7 to 9 years of age – 10 mg per day

• From 10 to 18 years of age – 12-15 mg per day

• From 19 to 65 years of age – 10-12 mg per day

• Pregnant women – 30 mg per day

• Breastfeeding women – 20 mg per day

Iron deficiency and its causes – what to look out for?

If there is a significant iron deficiency in our body, it affects our hair, skin, nails, mucous membranes and muscles. Due to too little iron in the blood, there may also be a risk of developing anaemia.

The symptoms of iron deficiency include:

• Chronic fatigue

• Apathy

• Pale skin

• Brittle nails

• Hair and nail growth disorders

• Skin and mucous membrane diseases

Iron deficiency can only be detected by performing a preventive blood test. Plasma iron concentration is assessed using values such as transferrin and ferritin. They play a key role in assessing the current level of iron in the patient's blood.

What is the reason for iron deficiency? There are many causes. These can include chronic inflammation, kidney dysfunction, or excessive or frequent blood loss during menstruation and other bleeding. Chronic diseases such as Crohn's disease and gluten intolerance can also cause iron deficiency. Low iron levels in the blood are replenished through dietary changes or supplementary treatment in the form of dietary supplements.

Causes of excess iron in the body – how does it develop?

If we regularly take iron supplements, even if only because of a trace element deficiency in the blood, we should pay attention to the correct dosage. Frequent overdosing, associated with consuming excessively high doses of the element, can lead to a sudden increase in blood iron levels.

Symptoms of excess iron in the body include:

• Vomiting

• Diarrhoea

• Bloody stools

• Increase in white blood cell count

Excess iron in the body may be caused by, for example, haemolytic anaemia, haemochromatosis, excessive iron intake, blood cancer (leukaemia) or severe liver damage associated with inflammation.

Iron during pregnancy – is it important?

During pregnancy, the expectant mother's body undergoes many changes. One of them is an increase in total blood volume. Therefore, pregnant women need larger amounts of this trace element so that their organs can function properly and the baby can develop without any negative changes.

Pregnant women have twice the iron requirement of non-pregnant women. In addition to the aforementioned increase in blood volume, this increased requirement is also due to the unborn child itself. The recommended amount of iron, approximately 30 mg per day, is difficult to achieve, even with a proper diet rich in macro- and micronutrients.

Even the slightest iron deficiency can worsen orthostatic hypotension, causing shortness of breath, dizziness and fatigue. In the case of iron deficiency in pregnant women, a gynaecologist prescribes iron supplements to meet the daily requirement.

Bibliography

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‘Iron in Health and Disease: An Update’ – A. Lal, scientific journal Indian Journal of Paediatrics, Springer, 2020.

‘Iron stores in man in relation to diet and iron requirements’ – L. Hallberg, L. Hulthen, L. Garby, European Journal of Clinical Nutrition, Nature Publishing Group, 1998.

‘Molecular and Cellular Iron Transport’ – D. Templeton, Marcel Dekker, 2002.

‘Proteins of Iron Metabolism’ – U. Testa, CRC Press, 2002.

‘Review on iron and its importance for human health’ – N. Abbaspour, R. Hurrell, R. Kelishadi, Journal of Research in Medical Sciences, IUMS, 2014.

‘The impact of a meat- versus a vegetable-based diet on iron status in women of childbearing age with small iron stores’ – I. Tetens et al., European Journal of Nutrition, Springer, 2007.