Iron – everything you need to know about the blood-forming trace element

Iron is an extremely valuable, vital mineral , and without it we would literally be thin-blooded. That is why I would like to give you everything you need to know about this topic in this post.

Among other things, it will be about: What exactly is iron anyway? What is it responsible for? What Are the Best Ferrous Foods? How is iron deficiency or toxicity expressed?

You will also learn how you can improve your iron absorption. 

What is iron

Iron is present in our body with a mass fraction of less than 50 mg per kg of body weight. Because of this, it is considered a trace element.

Although we only need traces of it, it is vital because our organism cannot synthesize it itself. Consequently, it must be ingested through food.

Mother nature is kind to us in this regard, because there are a multitude of foods that contain the element – vegetable as well as animal.

But be careful: animal and vegetable iron are different. The former is also known as heme iron or divalent iron ; this form of iron can be easily absorbed. The latter is also known as non-heme iron or trivalent iron . Because it is bound to substances that can inhibit iron absorption, it is less bioavailable.

By the way, our body can only absorb both forms up to a certain percentage. Up to 40% heme iron can be absorbed by the body [1]. The rate is significantly lower for vegetable iron (2 to 20%).

What role does iron play in the body?

Iron is essential and fulfills important functions in our body. In the following I would like to introduce you to some of the relevant functions of iron:

# 1 blood formation

Iron is an element that plays a key role in blood formation. Strictly speaking, it is required for the formation of hemoglobin, which is largely made up of iron.

Hemoglobin is a protein that is part of the red blood cells and gives our blood its typical red color – this is why it is also known as the red blood pigment.

But that’s not all: Hemoglobin is used to transport the oxygen we breathe to our body tissues.

Ergo: If we lack iron, not enough hemoglobin could be produced. Our tissues would be less oxygenated and we would feel tired and exhausted – typical symptoms of iron deficiency anemia.

Incidentally, hemoglobin also makes our skin shine in a healthy shade of red. An iron deficiency is therefore often revealed by an unnatural paleness.

# 2 Immune function

Low iron levels are linked to an increased risk of infection. Iron contributes to normal immune function because it is required for the formation and maturation of immune cells [2].

At the same time, iron is essential for viruses and bacteria to multiply. Too much of the element can therefore have the opposite effects and increase the risk of infection. Fortunately, our immune system has mechanisms that reduce the availability of the trace element and thus disrupt the growth of the pathogen [2].

# 3 energy metabolism

Without iron, no oxygen would get into our cells and no energy could be produced. In the cell, too, the production of energy is directly linked to iron – as it is required for the cytochrome C oxidases in the mitochondria . The trace element thus supports your energy metabolism.

# 4 Cognitive function and nervous system

Since iron or hemoglobin also ensures the oxygen supply to our brain, the element contributes to normal cognitive function.

An adequate supply therefore benefits our thinking apparatus and influences our memory, our concentration and our ability to solve problems in a positive way.

In addition, the trace element is required for the formation of dopamine. The neurotransmitter is used, among other things, to transmit signals from the brain to the musculoskeletal system.

Read More  Iron Deficiency - 10 Reasons You Should Avoid It!

# 5 muscle function

Hemoglobin is certainly known to many – but have you ever heard of myoglobin? Myoglobin is a muscle protein found in mammalian heart and skeletal muscle cells and is also known as red muscle dye. In terms of its structure, it is very similar to hemoglobin.

Myoglobin is heme-based and is able to absorb and release oxygen in order to ensure the transport of oxygen within the muscles.

# 6 detox

The trace element is also involved in the context of detoxification, because many of the enzymes required for this process are iron-dependent (including the cytochrome P450 oxidases).

# 7 antioxidant

Iron also has an antioxidant effect. It catches free radicals and is also a cofactor of catalase, an antioxidant enzyme that can neutralize 30,000 free radicals per second (!). Antioxidant enzymes are therefore an absolute foundation for your health in order to prevent oxidative stress . ( Incidentally, zinc , copper and manganese also need these enzymes)

# 8 thyroid

Your thyroid needs iron for an enzyme called thyroid peroxidase. This enzyme fixes iodine to the amino acid tyrosine and thus forms the thyroid hormone thyroxine (fT4). Therefore, iron deficiency can be related to an underactive thyroid.

How much iron does the body need?

How much is needed per day depends on both age and gender. Adult women require 15 mg per day; Men only 10 mg.

Older children and adolescents who are in the growth phase have an increased need for the essential trace element. Boys need about 12 mg, girls 15 mg per day.

Furthermore, athletes have a significantly higher need, as a lot of iron is lost through sweat, pregnant women (30 per day) and breastfeeding women (20 mg per day).

Especially ferrous foods

You now know what your body needs iron for. However, it remains to be seen where you can get it from. That is why you will find a wide variety of iron-containing foods (including their content) below, which are worth integrating into your everyday diet.

# 1 offal and red meat

Before you jump to the next point because you don’t like the thought of eating organ meat, let the following work on you: Organ meat is one of the most nutritious foods of all and is full of minerals and vitamins (e.g. vitamins A and B).

If properly prepared, offal is not only healthy, but also delicious (take a look at our Franconian liver dumpling soup here ).

In addition, from an animal ethical point of view, it is advisable not to dispose of organ meat as mere waste, but to use the parts for the sake of the animal. As the saying goes: ” From nose to tail “.

Also red meat from species-appropriate husbandry is extremely rich in nutrients such as iron.

  • Pork liver: 18 mg per 100 g
  • Red meat (e.g. beef tenderloin): 2.3 mg per 100 g

# 2 seafood

Delicious seafood such as oysters are not only rich in healthy fats and minerals such as selenium , copper and zinc, but also convince in terms of their iron content.

  • Oysters: 6.25 mg per 100 g


# 3 grain products

Grain products such as millet and oats are excellent vegetable sources of protein that are also good sources of iron. In addition, millet and oats are among the more easily digestible types of grain because they are gluten-free. (When buying oats, look out for gluten-free varieties!)

  • Millet: 9 mg per 100 g
  • Oats: 4.6 mg per 100 g

# 4 legumes

Legumes come in numerous colors and shapes. Because of their high protein content, they are popular alternatives to meat or eggs with vegetarians. Of course, their iron content is also considerable.

Unfortunately, they are full of anti-nutrients that affect their tolerability. For this reason, you should always soak them long enough (at least 12 hours) and boil them well.

  • Lentils: 7.5 mg per 100 g
  • Chickpeas: 6.9 mg per 100 g
  • White beans: 6.1 mg per 100 g

# 5 vegetables

You probably won’t be surprised when I tell you that spinach is a good source of iron. However, it does not contain as large quantities as is always claimed.

Furthermore, it must be borne in mind that spinach is vegetable and therefore contains the less bioavailable non-heme iron. However, if you combine spinach with sources of vitamin C (e.g. lemon, broccoli ) you can increase the intake rate.

  • Spinach: 4.1 mg per 100 g
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By the way : Popeye and spinach has a historical reason: There was a calculation error at the beginning of the 20th century, and it was thought that 100 g spinach contains ten times as much iron, namely approx. 40 mg. But even after correcting the error, it must be said that spinach is a food rich in iron.

Spinach – A classic with a good helping of iron!

# 6 Dark chocolate

Live healthy and still nibble on chocolate ? That’s fine. Chocolate with a cocoa content of at least 80% benefits your health in many ways and provides you with copper, magnesium and iron, among other things .

  • Dark chocolate: 12-15 mg per 100 g

Again in the overview and in comparison our iron-rich foods:

  • Pork liver: 18 mg per 100 g
  • Red meat (e.g. beef tenderloin): 2.3 mg per 100 g
  • Oysters: 6.25 mg per 100 g
  • Millet: 9 mg per 100 g
  • Oats: 4.6 mg per 100 g
  • Lentils: 7.5 mg per 100 g
  • Chickpeas: 6.9 mg per 100 g
  • White beans: 6.1 mg per 100 g
  • Spinach: 4.1 mg per 100 g
  • Dark chocolate: 12-15 mg per 100 g

If you want to live healthily, you don’t have to go without chocolate – on the contrary. Those who snack on the dark variant are also consuming valuable minerals such as iron.

Iron deficiency

Many people lack the essential trace element; women are affected more often (30-50%) than men (10-20%).

A deficiency can be the result of an impaired intake (e.g. due to one-sided nutrition or certain nutritional concepts) or a reduced intake (e.g. due to inflammatory bowel disease, medication intake).

Furthermore, an increased iron loss (due to exercise, blood donations, surgery) and an increased iron requirement (in the course of pregnancy or growth) [3] can lead to the development of a deficiency.

Symptoms of iron deficiency speak , are the following:

  • Anemia
  • Fatigue and loss of energy
  • paleness
  • shortness of breath
  • Headache and shingling sensation
  • Racing heart
  • dry and damaged skin and hair
  • brittle nails
  • Restless Legs Syndrom
  • Feeling cold
  • Pica Syndrome
  • Schildrüsenprobleme
  • low resilience, especially during sport and physical work

You can find out more about iron deficiency (causes, symptoms and how to prevent or eliminate it) here in our article on iron deficiency .


Our body is actually able to regulate the iron absorption from the intestine itself, so that there is no excess.

In this context, the hormone hepcidin plays an important role because it is able to suppress the absorption of iron when the iron stores are full and increase it when they are low.

As I said, the system normally regulates itself; nevertheless, iron toxicity can occur under certain circumstances:

  • Overdose of iron supplements [4]
  • Taking high-dose iron supplements for too long
  • Hemochromatosis (also iron storage disease = a genetic disease in which iron absorption in the intestine is disturbed and far more iron is absorbed than required)
  • repeated blood transfusions

The first symptoms that indicate iron poisoning are stomach pain, nausea, and vomiting. Long-term ingestion of too much iron can build up deposits in the liver and other tissues, which can cause damage.

Blood sugar is also negatively affected, as too much iron leads to oxidative stress and this promotes insulin resistance. If the iron and ferritin levels are elevated, I would pay particular attention to this.

Where can I have my iron levels determined?

Of course, like many other values, you can have your iron level determined by a doctor. The following values ​​are typically checked:

  • Hb value
  • iron in the blood
  • Transferrinsättigung
  • Ferritin (storage iron), should be at least 35 mg / dl

Incidentally, a low iron and high ferritin value can indicate a chronic infection in the body – the body would then like to “take away” the iron from the pathogens and store it in ferritin.

By the way, an alternative to visiting a doctor is a blood test to take at home. To do this, you take a blood sample yourself and send it to a certified laboratory using a prepaid letter. A few days later you go online and know about your values.

Our recommendation: The Lykon myHealth & Fitness * . With the help of this test, you can have other important vital parameters determined in addition to iron. With the discount code Gesund15 you save 15%.

Recommendation for an iron supplement: Gentle Iron from Edubily

If you do want to take an iron supplement – for whatever reason, it is important to focus on quality: Many iron supplements are dosed far too high or too low, have poor bioavailability – some also irritate the gastrointestinal tract.

Read More  Iron Deficiency - 10 Reasons You Should Avoid It!

We recommend Edubily’s “Gentle Iron” – a very well-tolerated and well-formulated preparation that contains 14 mg of iron per capsule as well as vitamin C and lactoferrin. It has excellent bioavailability and also strengthens the immune system.

>> Our recommendation: The “Gentle Iron” from Edubily *

Iron, vegetarianism and veganism

As mentioned earlier, the best sources are animal in nature (red meat and offal) as they contain valuable heme iron, which is characterized by excellent bioavailability.

In the context of the vegan and vegetarian diet, however, meat is taboo; For this reason, followers of these nutritional concepts are more likely to suffer from iron deficiency.

Interestingly, however, studies show that vegans and vegetarians consume as much, if not more, iron than people who incorporate meat into their daily diet [5–7].

Nonetheless, vegans and vegetarians are at increased risk of developing iron deficiency. This is because vegetable sources contain the less absorbable non-heme iron.

Maybe you are a vegan or a vegetarian and are wondering: How can I improve my intake? Well, then be curious and read on …

How you can positively influence the absorption of iron

Some substances are able to improve iron absorption when they are consumed in combination with foods containing iron.

1. Vitamin C

Vitamin C is able to “capture” non-heme iron and store it in a form that the body can absorb more easily, namely as a divalent ion (Fe2 +) [1]. All you need to do is fortify your meal with good sources of vitamin C.

Vitamin C is contained in: citrus fruits, spinach, Brussels sprouts, kale, broccoli, parsley, paprika and black currants.

2. Vitamin A and beta-carotene

Vitamin A is linked to maintaining our eyesight as well as our bone growth. Beta-carotene, also called provitamin A, is a precursor to vitamin A.

One study showed that the absorption of iron after cereal-based meals was significantly improved by the presence of vitamin A or beta carotene [8].

Vitamin A and beta-carotene are found in: carrots, sweet potatoes, spinach, kale, pumpkin, red peppers, melons, apricots, oranges and peaches.

3. Meat, fish and poultry

As you now know, foods of animal origin contain valuable heme iron. Additionally, these foods can also stimulate the absorption of non-heme iron. Studies confirm this effect [9–10].

At the same time, there are substances that can hinder absorption:

1. Phytat

Studies show that even small amounts of phytate (including phytic acid) are sufficient to inhibit iron absorption [3; 9]. It is contained in: whole grain products, cereals , soy, nuts and pulses [1].

Simultaneous consumption of meat or foods containing vitamin C can compensate for the effect of phytate.

2. Calcium

Calcium is known to be important for our bone health, but there is evidence that dairy products, like calcium supplements, can get in the way of iron absorption [9; 11]. However, the issue has not yet been finally clarified. To make sure that your iron intake is optimal, you could try to avoid calcium-containing products during meals that are particularly rich in iron and not take calcium and iron supplements at the same time.

3. Polyphenole

Polyphenols are substances found in plant-based foods and some beverages (tea, coffee and wine). Coffee and tea in particular have a high content and can inhibit the absorption of non-heme iron [12]. If the corresponding drinks are consumed between and not during meals, the adverse effect can be reduced [9].

Summary – The most important things at a glance

  • Iron is an essential trace element that is available in the form of easily absorbable heme iron (animal foods) and less absorbable non-heme iron (plant foods).
  • The element makes a significant contribution to this: blood formation, immune function, cognitive function, energy metabolism, muscle function, detoxification, neutralization of free radicals.
  • The amount that is needed every day depends on factors such as age and gender. Women usually need more than men.
  • The best iron-containing foods are: pork liver, red meat, oysters, millet, oats, lentils, chickpeas, white beans, spinach, and dark chocolate.
  • If there is a lack of iron, there is a risk of anemia, tiredness, loss of energy and paleness. At the same time, too much of the trace element should be avoided, because high amounts (especially over a longer period of time) lead to poisoning.
  • Vitamin C and A as well as beta carotene can promote absorption. If you combine foods that contain heme iron with those that contain non-heme iron, you improve the absorption rate of the latter.
  • Phytate, calcium and polyphenols can inhibit absorption.

>> Our recommendation for an excellent iron preparation: The “Gentle Iron” from Edubily *

We hope you enjoyed the article. Do you still have questions? Get in touch!

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