Iron is needed for the formation of red blood cells’ haemoglobin. In addition, it acts as a catalyst in many enzyme reactions.
Iron affects your coping, well-being and mood
Iron is essential for the body. It affects many bodily functions. One of its main tasks is to transport oxygen to important organs such as the heart and muscles.
Iron is essential for people
- Iron acts as an oxygen-binding component of red blood cells’ hemoglobin.
- The recommended iron intake is higher for women than for men.
- The best sources of dietary iron are liver, meat and whole grain products.
- Iron deficiency is the most common cause of anemia.
Iron is essential for the body
Iron is an essential mineral, more specifically a micronutrient, for the body. It affects many bodily functions. One of its main tasks is to transport oxygen to important muscles and organs, such as the heart.
Normal iron values help to prevent anemia and to stay refreshed and healthy. Low iron values lead to poor health but, on the other hand, high values can also cause health problems.
The body cannot produce iron, so it must be obtained through food every day. Iron is eliminated from the body with secretions, which is why regular intake is important.
Iron deficiency is the most common nutrient deficiency in the world.
Functions of iron
The main function of iron is to participate in the transport of oxygen as a component of red blood cells’ hemoglobin.
Why is iron intake so important?
Adequate iron intake ensures normal energy levels and coping. Iron must be obtained through food every day as our bodies cannot produce it. Ferritin is the primary test if iron deficiency is suspected.
Storage of iron
The majority of the body’s iron is functional, usable iron. However, iron is also stored in ferritin. In addition to many other factors, the amount of iron stored in the body is influenced by the time of day and, in women, the stage of the menstrual cycle. In other words, the iron content in the body is not constantly the same.
Iron absorption is complex
Although iron is obtained from food, its absorption in the body may be poor. Iron is absorbed by the body from the small intestine, which plays an important role in regulating the amount of iron in the body. Coeliac disease and other conditions related to malabsorption, for example, can affect the absorption of iron.
In coeliac disease, the protein gluten contained in rye, wheat and barley damages the villus on the mucous membrane of the small intestine, which can cause nutrient absorption disorders. This may lead to poor absorption and deficiency of nutrients such as iron. The method of treating iron deficiency is determined according to the causes of the condition. If the cause is coeliac disease, it must be treated appropriately. It can also support the absorption of iron in the future.
Vitamin C helps the absorption of iron. When eating iron-rich foods or iron supplements, you should also ensure proper vitamin C intake, for example, from fruits or berries. Many iron supplements contain vitamin C.
Certain foods and beverages restrict the absorption of iron. Calcium (contained in dairy products or calcium-enriched plant-based drinks, such as oat drinks), magnesium supplements, coffee and tea impair the absorption of iron, which is why iron supplements should not be taken when eating or drinking these.
Certain medications may also interfere with the absorption of iron. Consult your doctor for detailed instructions.
Iron is best absorbed when iron stores are scarce. As the level of iron in the body increases, absorption gradually diminishes.
Iron level tests
The two most common blood tests used to assess iron levels are hemoglobin and ferritin tests. Iron test is also available, but when assessing iron deficiency, hemoglobin and ferritin are more important. An iron test is primarily carried out as an additional test when determining the transferrin saturation.
The hemoglobin test is the most common blood test in healthcare. It is used to diagnose iron deficiency anemia. Hemoglobin is part of the complete blood count.
Reasons for performing a ferritin test:
- assessment of the body’s iron levels
- diagnosis of iron deficiency if the person has anemia or belongs to a high-risk group
- differential diagnosis of iron deficiency anemia or anemia due to other causes
- monitoring of iron supplement treatment if an iron supplement has been used to treat iron deficiency and its effectiveness needs to be monitored
- people at risk of iron deficiency: pregnant women, the elderly, blood donors, people on strictly vegetarian diet and people with intestinal diseases.
How much iron is needed from diet?
The recommended intake of iron for men is 9 mg/day and 15 mg/day for women of reproductive age. The required iron intake for postmenopausal women is only 9 mg/day, which is also the level recommended for men.
The recommended intake for women is higher than for men due to menstruation. A lot of iron is lost during menstruation. Some women may have such heavy periods that a daily dose of 15 milligrams of iron is not enough.
The need for iron increases during pregnancy. Pregnant women are recommended by the maternity clinic staff to take iron supplements, if necessary. A daily iron intake of 15 mg is recommended for breastfeeding women. The maternity clinic monitors the hemoglobin value, which is an indicator of anemia.
On average, only 15% of the iron in food is absorbed, which is taken into account in the iron intake recommendations.
Iron deficiency is a common problem
Iron deficiency may occur if:
- there is not enough iron in the diet
- there is insufficient absorption of iron
- a lot of iron is lost.
What are the causes of iron deficiency?
Low iron values can be caused by, for example:
- low dietary iron intake
- blood loss due to menstruation, repeated blood donations, bleeding, childbirth or, for example, an ulcer in the digestive system
- a child’s rapid growth
- malabsorption disorders such as coeliac disease (insufficient iron absorption)
- pregnancy (increased need for iron)
- physical activity (increased need for iron).
Iron deficiency is treated according to the cause. Iron stores can be replenished with food and, if necessary, iron supplements. If iron deficiency is caused by an illness, it must be treated.
What are the high-risk groups for iron deficiency?
Certain people are at a higher risk of receiving too little iron from their diet. Low iron intake can develop into iron deficiency anemia.
Pay particular attention to your iron values and iron intake if you belong to the following groups:
- Women of reproductive age – menstruation depletes your iron stores every month. Heavy menstrual bleeding can cause severe iron deficiency.
- People with unvaried diets. A varied diet is the most important way to prevent iron deficiency.
- Pregnant and breastfeeding mothers: pregnancy itself increases the need for iron while the mother must also get sufficient iron for the child.
- Children, especially adolescent girls
- Physically very active people and athletes
- People with coeliac disease or other malabsorption syndromes
- People with inflammatory bowel disease
- People who have experienced heavy bleeding, for example, due to accidents, surgery or childbirth.
- Persons who have repeatedly donated blood.
- The elderly
- People on a vegetarian or vegan diet should pay attention not only to their iron intake but also its absorption. However, iron deficiency is typically associated with heavy menstrual bleeding and not whether or not the diet includes animal products.
What are the consequences of iron deficiency?
Low iron levels can cause a wide range of symptoms. Iron deficiency is the most common cause of anemia. However, anemia may be associated with lack of vitamin B12 and folic acid. The symptoms develop unnoticed and it is possible to get used to them and think that they are part of normal life.
Iron deficiency anemia may be associated with the following symptoms:
- tiredness
- poor physical performance and general condition
- palpitations
- shortness of breath
- dizziness
- weakness
- paleness, pale gums
- headache
- ringing in the ears
- hair loss and thinning, poor nail and skin condition
- restless legs
- oral symptoms, such as the sensation of a lump in the throat, ulcers in the mouth and corners of the mouth, lingual papillae lesions, tongue pain, difficulty swallowing
- sleep disorders
- depression-like symptoms.
The more severe the anemia, the stronger the symptoms.
These symptoms may also be related to another condition or disease. If you suspect an illness or have symptoms, seek medical attention directly.
Is it possible to get too much iron?
Excessive intake of iron is extremely rare, but it is possible in principle. In general, it is not possible to get too much dietary iron. Excess intake is usually associated with a disorder of iron absorption (in which case too much iron is absorbed) or the use of an iron supplement (oral supplement or intravenous iron infusion).
Iron can accumulate in the body. In most cases, repeated blood transfusions are responsible for excess intake of iron and the use of iron supplements is rarely the reason behind it. The maximum dose of the iron supplement should not be exceeded. In the case of children, in particular, iron supplements should be used with care and the instructions given by the doctor must be followed.
Excessive iron intake can weaken the immune mechanisms of the body. Therefore, excessive iron increases the risk of infections to some extent.
If a dietary supplement or other iron-based products are used moderately, it is unlikely that too much iron would accumulate in the body.
An example of the adverse effects of iron is hereditary hemochromatosis. Hemochromatosis is a condition in which the body stores too much iron. The condition stems from a gene mutation that increases the absorption of iron through the intestines.
What are the sources of iron? Best sources of dietary iron
The best sources of dietary iron are liver, meat and whole grain products.
What are good sources of dietary iron?
The following foods, for example, are great sources of iron:
- Blood and liver dishes
- Bran, flakes and groats high in fibre
- Pumpkin seed, sesame seed and hemp seed
- Lentils
- Black beans, white beans, brown beans, soybeans and broad beans
- Black sausage
- Bovine liver
- Nuts (especially cashew nuts) and almonds
- Chickpeas
- Liver sausage
- Game meat
- Fried venison
- Quinoa
- Beef roast
- Liver casserole
- Minced meat
- Tuna
- Spinach, nettle and arugula
- Pasta, potatoes and rice
- Eggs
- Clams, crustaceans and fish
- Broccoli, pea, Jerusalem artichoke and black root
- Dried basil and oregano
- Plums
Which foods support the absorption of iron the best?
Iron (heme iron) is best absorbed from animal products, but it is also possible to get enough iron from plant products (non-heme iron).
What are the sources of iron for vegetarians?
Vegetarians and vegans can get enough iron from their diet. Vegetarians should pay attention to the absorption of iron in addition to iron-rich foods (for example, avoiding coffee, tea and dairy products when eating iron-rich foods).
The following plant-based foods contain iron, among others:
- hemp seeds
- poppy seeds
- pumpkin seeds
- chia seeds
- sesame seeds and tahini or sesame seed paste
- lentils
- boletus pinetorum
- soybeans and soy products (such as tofu, soybean protein powder, soybean meal and soybean flour)
- black beans, white beans, brown beans and broad beans
- linseed
- pine nuts
- pulled oats
- cashew nuts
- sunflower seeds
- bran, flour and flakes
- pea shoots
- chickpeas
- almonds
- peas
- quinoa
- pasta, spaghetti, macaroni
- pistachios
- whole grain products, whole grain bread and whole grain pasta
- seed mixes and crisp seed breads.
What promotes the absorption of dietary iron?
Foods containing iron should be accompanied by foods rich in vitamin C, such as vegetables and fruits, as vitamin C promotes the absorption of iron. For example, blackcurrants contain a lot of vitamin C.
What restricts the absorption of dietary iron?
Certain nutrients restrict the absorption of iron, for example the calcium contained in dairy products, magnesium supplements, coffee, tea and brans. If the aim is to increase iron levels, these foods should be consumed separately from iron-rich foods.
Iron supplements should usually be taken with an empty stomach.
How do iron stores affect iron absorption?
The absorption of iron is improved when the body’s iron stores decrease. In turn, higher iron stores effectively reduce the absorption of iron.
What is heme iron?
The heme iron contained in meat and fish is better absorbed than the iron contained in plant-based foods. Heme iron is only found in products of animal origin.
What is non-heme iron?
Non-heme iron is found in plant products. The heme iron from animal products is better absorbed than the non-heme iron from plant products.
FAQ
Iron can be obtained from a varied diet that includes red meat, chicken, fish, legumes, nuts, and whole grains. Iron is also found in many green leafy vegetables such as spinach and kale. The absorption of iron can be enhanced by consuming foods containing Vitamin C at the same time.
Iron supplements can darken the stool within a few days of use. This is a normal reaction and indicates that the iron is passing through the digestive tract.
Iron levels are measured with a blood test that assesses several indicators, such as serum iron, ferritin, and transferrin. The blood test can be done on a doctor’s referral or at self-service laboratories like Vital, where you can order the test without a doctor’s referral. Results are usually available the next business day.
The recovery from iron deficiency depends on many factors, such as the degree of iron deficiency and the intake of iron from diet or supplements. Generally, alleviating symptoms and replenishing iron stores can take several weeks or months. Regular monitoring with blood tests is recommended.
The daily amount of iron supplement depends on the person’s age, gender, and health condition. Adult women are generally recommended to take 15-18 mg of iron per day, while adult men need 8-10 mg. The need may be greater for pregnant and breastfeeding women. Follow the doctor’s instructions.
Iron tablets should be taken on an empty stomach, about an hour before a meal or two hours after a meal to maximize iron absorption. Avoid consuming coffee, tea, dairy products, and calcium supplements at the same time as the iron tablets, as they can reduce the absorption of iron.
Iron levels can begin to rise after a few weeks of regular use of iron supplements, but full benefits are usually achieved within 2-3 months.
Iron deficiency can manifest as fatigue, weakness, dizziness, and paleness. Shortness of breath and heart palpitations may also occur. Iron deficiency is diagnosed using blood tests, such as ferritin measurement.
Iron levels can be increased with regular use of iron supplements, a varied diet rich in iron (such as red meat, spinach, legumes) and by avoiding substances that interfere with iron absorption during meals.
The duration of iron supplementation depends on the individual’s iron stores and the doctor’s recommendation. Typically, an iron regimen lasts several months until the iron stores are restored to normal levels. It is important to regularly monitor iron levels through blood tests.
Iron is best absorbed when taken with vitamin C and avoiding simultaneous intake of calcium and coffee, which can interfere with iron absorption.
An iron infusion can improve iron levels and well-being within a few days. Full effect is usually seen within a few weeks.
Iron begins to absorb from the intestine into the bloodstream within a few hours of ingestion, but full effects are often only seen after weeks of regular use.
Iron infusion is recommended when iron deficiency is severe or when iron supplements have not been effective or have caused side effects.
The effects of iron can be felt as increased energy levels and reduced fatigue after a few weeks of regular use.
Iron supplements should be taken on an empty stomach, preferably in the morning, to ensure the most effective absorption. Avoid taking iron with products containing calcium.
The recommended daily intake of iron for adults varies depending on gender and age, but typically 10-18 mg per day is recommended.
Laboratory package Iron deficiency Total includes 12 values that provide insight into your iron levels, iron stores, and whether you suffer from any potential anemia.
Laboratory package Iron deficiency Basic includes 10 values that provide you with insight into your iron levels.
Ferritin, iron deficiency, and iron deficiency anemia: Symptoms, measurement, and treatment
Ferritin indicates the amount of iron stored in the body. Low ferritin level is a sign of low iron stores.
Hemoglobin (Hb) – Measurement and reference values
When suspecting anemia, it is important to test the hemoglobin. Symptoms of iron deficiency anemia include paleness and fatigue.
Long-term glucose levels, hemoglobin A1C, B-HbA1c
Hemoglobin A1C indicates the glycated hemoglobin (long-term glucose levels) in the blood. Hemoglobin A1C, or glycated hemoglobin, shows your average blood glucose levels over the previous 2–8 weeks.
Folate (vitamin B9) is especially important for pregnant women
Lack of folate can cause, among other things, nervous system symptoms, growth retardation and megaloblastic anemia.
Mean corpuscular volume of red blood cells (MCV)
MCV is tested when looking for the causes of diagnosed anemia.
Hematocrit, volume percentage of red blood cells in blood
Hematocrit measures the percentage of red blood cells in the blood. In anemia, the red blood cell count is reduced.
Article updated:
23 October 2024