Iron - More than just a metal

Iron is essential for hemoglobin, the protein complex that gives our blood its red color. Hemoglobin is found in all of our red blood cells, the erythrocytes. It is vital for us because it binds oxygen and transports it to our cells via the bloodstream. If the body lacks iron, anemia can occur. This is known as iron deficiency anemia, the most common nutritional deficiency disease worldwide. In this article, you will learn what you need to pay attention to when it comes to iron and what you can do to prevent iron deficiency. avoid.

Table of contents

• What is iron?
• Causes of iron deficiency
• How can iron help?
• How does iron from food get into the blood?
• What inhibits the absorption of iron?
• Normal values ​​for iron in the blood
• Symptoms of iron deficiency
• How can I prevent a deficiency?
• What happens if you overdose on iron?
• Iron intake recommendations
• Bioavailability of iron
• Overview of iron-containing foods
• Conclusion
• Sources

What is iron?

Iron is an important trace element and essential for life . It cannot be produced in the human body and must therefore be supplied. Iron plays a central role in our metabolic processes and, among many other functions, is responsible for the transport of oxygen in the blood.

Every cell in our body needs iron for its energy balance.

Iron is essential for hemoglobin, the protein complex that gives our blood its red color. Hemoglobin is found in all of our red blood cells, the erythrocytes. It is vital for us because it binds oxygen and transports it to our cells via the bloodstream.

If there is not enough iron intake, a deficiency can occur. A blood test is carried out to determine the iron level.

What are the causes of iron deficiency?

The most common causes of iron deficiency are malnutrition and bleeding . (1) In women, iron deficiency can be caused by recurrent heavy bleeding during menstruation. Bleeding in the gastrointestinal tract can also lead to increased blood loss and thus cause iron deficiency. Since the body cannot produce iron itself, it must be supplied through food.

In terms of nutrition, not only does a sufficient intake of iron-containing foods play an important role, but also the absorption of iron in the intestine. If there is a gluten intolerance (celiac disease), this can lead to an absorption disorder and thus also to an iron deficiency. In the case of an absorption disorder, the body theoretically finds iron, but cannot absorb it in sufficient quantities due to impaired intestinal function. An iron deficiency should be avoided at all costs, as iron is important for many metabolic processes in our body. You will find out exactly which ones in the next section.

How can iron help?

Within the framework of the Health Claims Regulation, it was tested and confirmed that iron…

• contributes to the normal formation of red blood cells
• contributes to normal energy metabolism
• to a reduction in fatigue is
• contributes to the normal function of the immune system

In addition, iron fulfills important functions in metabolism. Iron plays an important role not only in oxygen transport and oxygen absorption, but also in cell function and electron transport in the mitochondria, the power plants of our cells. In addition, iron is a component of enzymes such as cytochromes, catalase and peroxidases. Cytochromes play an important role in the electron transport chain as part of energy production in the body. Catalases sometimes require iron-containing heme as a cofactor in order to become biochemically active. These convert hydrogen peroxide, which is harmful in high concentrations, into oxygen and water. Peroxidases often serve to detoxify other peroxides, which are cell toxins. Iron plays an important role in many of these metabolic processes. You can see that iron is more than just a metal. Without iron, complex and vital reactions in our body would not take place completely and correctly.

How does iron from food get into the blood?

Iron is absorbed in the intestine and enters the blood. A distinction must be made between iron from animal and plant-based foods. Animal iron is usually present as heme iron, a component of hemoglobin. Plant-based iron is present as non-heme iron (Fe3+). In order for the body to absorb the trivalent form of iron (Fe3+), the body must first convert it into a soluble form (Fe2+).

What inhibits the absorption of iron in the intestine?

Iron absorption can also be influenced by food. Phytates from soybeans, lentils or brown rice can inhibit the absorption of iron in the intestine. Certain ingredients from milk and dairy products, coffee or black/green tea can also impair iron absorption. Dairy products are rich in calcium, which can inhibit iron absorption in the intestine. Coffee and black/green tea contain tannins, which also inhibit the absorption of iron in the intestine. Vitamin C from fruits and vegetables, on the other hand, can increase iron absorption. (2,3)

Therefore, always make sure to combine iron-containing foods or iron supplements with a food containing vitamin C and not to consume coffee, green or black tea 30-60 minutes beforehand. This will ensure that the iron can be absorbed into the blood through the intestines as best as possible. You can find out what iron blood levels are normal in the next section.

What are normal values ​​for iron in the blood?

The normal values ​​for iron in the blood vary depending on age and gender. There are also different normal values ​​during pregnancy (see Table 1).

Did you know? Iron is bound in the body. For example, in the hemoglobin molecule, as depot iron (ferritin, hemosiderin), myoglobin, transferrin (transport iron) and in iron-containing enzymes.

Other important laboratory parameters relating to iron are hemoglobin, transferritin, serum ferritin and C-reactive protein. The hemoglobin value indicates the concentration of the red blood pigment, hemoglobin, in the blood serum. However, the hemoglobin value cannot be used to draw any conclusions about the iron stores in the body. For this, serum ferritin is measured. This value can be used to determine how full the iron stores in the body are. The transferritin can in turn be used to determine how much iron is transported in the body.

How do you notice an iron deficiency?

A lack of iron usually manifests itself in the form of paleness, tiredness, listlessness and brittle nails . More general symptoms such as shortness of breath, dizziness, headaches, forgetfulness, difficulty concentrating, loss of appetite, dry skin and increased susceptibility to infections can also be signs of iron deficiency. In rare cases, a long-term iron deficiency can also lead to other diseases such as Plummer-Vinson syndrome or pica disease. In Plummer-Vinson syndrome, the mucous membrane in the mouth and throat recedes and the corners of the mouth crack. In pica disease, those affected put inedible objects in their mouths such as soil, paper or sand. Sometimes metal objects are also put in their mouths. According to current knowledge, an iron deficiency can also be the cause of this disease. (4)

Growth disorders can also occur in children. During pregnancy, iron deficiency can lead to significant complications such as premature births and miscarriages. Therefore, you should always ensure that you consume sufficient iron-rich foods and have your blood checked regularly (if you suspect iron deficiency). If iron deficiency is diagnosed, you should consult a doctor and take an iron supplement. (5)

In addition, iron deficiency also has a significant impact on performance in sports. Why? Iron is needed for normal energy metabolism. If the body lacks iron, fatigue and reduced endurance performance can be the result.

An iron deficiency has a negative effect on athletic performance. Endurance athletes are particularly affected by an iron deficiency. The reason: increased sweating over longer periods of time. Many athletes try to prevent a deficiency by taking iron and increase their performance. However, this can also lead to an iron overdose. More on this in the next section.

What happens if you overdose on iron?

In healthy adults, an overdose of iron through dietary intake does not usually occur. However, a very high intake of iron through iron supplements can lead to an overdose. The risk of an overdose increases particularly when people fear they are suffering from an iron deficiency and take iron supplements as self-medication. Therefore, be sure to speak to your doctor beforehand. Elevated iron levels that cannot be attributed to deliberate supplementation can also be associated with some types of cancer and are also suspected of increasing the risk of arteriosclerosis, as free iron ions promote the formation of oxygen radicals. An acute overdose can manifest itself in vomiting, diarrhea, fever, abdominal pain and bleeding in the digestive tract.

What dosage is recommended?

The requirement varies depending on the phase of life and is very individual. We lose around 1 mg of iron per day through stool, urine and sweat.

The daily iron requirement changes depending on age, gender and living conditions. Young people between 10 and 19 years of age have a higher iron requirement than younger children and older people. Pregnant and breastfeeding women in particular have a much higher requirement. The German Nutrition Society (DGE) recommends that women of childbearing age consume 15 mg of iron a day through their diet; for pregnant women this recommendation is 30 mg and for breastfeeding women 20 mg. Men and women after the menopause need 10 mg of iron per day. (7)

If iron deficiency anemia is diagnosed, the recommendations change significantly. Please discuss this with your doctor.

Bioavailability of iron

Red meat is a particularly bioavailable source of iron because it contains the blood pigment hemoglobin and the iron is easily absorbed by the body. Vegetarians and vegans can combine various plant-based foods to increase iron absorption in the intestine. Foods containing vitamin C such as peppers, oranges and broccoli increase iron absorption in the intestine (3).

Our tip: Combine foods containing vitamin C with iron-rich foods such as oats, millet, chickpeas or tofu. Among stone fruits, pistachios and cashews have a particularly high iron content.

However, it is often not easy to ensure an adequate supply in everyday life. If your doctor subsequently diagnoses an iron deficiency, you should resort to iron tablets.

How can I prevent a deficiency?

In general, it is recommended to ensure that you get enough iron in your diet. In addition, you can improve your iron levels by taking iron supplements in consultation with your doctor. In general, anyone who consciously eats iron-rich foods will do a lot to prevent iron deficiency.

Which foods provide iron?

Iron supplementation is useful if you have an existing iron deficiency . Supplementing on your own is not recommended, as it can lead to a dangerous oversupply. Elevated iron levels are considered a risk factor for coronary heart disease such as arteriosclerosis and heart attacks, as free iron ions promote the formation of oxygen radicals. In general, women who have a heavy blood loss during their period should discuss iron deficiency with their doctor. Other people with an increased need for iron include pregnant women, infants, children, adolescents, athletes, blood donors and vegans.

What should you look for when buying an iron supplement?

When buying iron tablets, make sure that it is divalent/heme iron (Fe ²⁺ ) rather than trivalent/non-heme iron (Fe ³⁺ ). This is more bioavailable because trivalent iron must first be converted into the soluble form, Fe ²⁺ . (5) In addition, you should ensure an optimal dosage. This depends on the severity of the iron deficiency. Ask your doctor about this. Are you vegetarian or vegan? Ask your pharmacist for a vegan capsule shell.

Conclusion

This vital trace element should always be consumed in sufficient quantities. When consuming iron-containing foods or an iron supplement, there are a few points to consider to ensure optimal absorption. For example, you should always combine it with a food rich in vitamin C and avoid consuming coffee, green or black tea at the same time. If you are diagnosed with an iron deficiency, make sure you take the optimal dosage of the iron supplement to avoid an excess of iron. Before taking an iron supplement, you should have your body's iron supply determined using the blood markers ferritin, transferritin, hemoglobin and C-reactive protein. Only then can you be sure that you have an iron deficiency. You can then select a suitable iron supplement in consultation with your doctor. It is generally advisable to eat a varied and wholesome diet. This allows you to integrate iron-containing foods into your diet in a natural way.

Sources:

(1) KÜBLER, W.; ANDERS, HJ; HEESCHEN, W.: VERA series, Volume V, Supply of adults with minerals and trace elements in the Federal Republic of Germany. Scientific specialist publisher, Niederkleen 1995

(2) MORCK TA, Lynch SR, Cook JD. Inhibition of food iron absorption by coffee. 1983.

(3) LYNCH SR, Cook JD. Interaction of vitamin C and iron. 1980.

(4) Singhi S, Singhi P, Adwani GB. Role of psychosocial stress in the cause of pica. Clin Pediatr (Phila). 1981 Dec;20(12):783-5. doi: 10.1177/000992288102001205. PMID: 7307412.

(5) FEDERAL INSTITUTE FOR RISK ASSESSMENT: Iron is not the same as iron - what is the difference between plant and animal iron? Available at: https://www.bfr.bund.de/cd/28369

(6) BITSCH, R.: Iron requirements and vegetarian nutrition. In: Nutritional Review 6/43, vol., pp. 214-217, 1996

(7) GERMAN NUTRITION SOCIETY: Reference values ​​for iron. Available at: https://www.dge.de/wissenschaft/referenzwerte/eisen/?L=0