Iron is an important mineral and is a part of many body functions. Iron helps make the oxygen stored in our muscles usable. As part of the haemoglobin, iron helps move oxygen from our lungs to the rest of our body.
Iron deficiency is commonly associated with developing anaemia, a condition in which not enough healthy red blood cells are produced. Iron supports the conversion of proteins, it also plays a major role in the production of haemoglobin and red blood cells and prevents the development of anaemia.
Iron plays a role in many of the enzyme reactions that help our bodies digest food and absorb nutrients. These reactions also balance the hormonal balance and support the brain, heart, skin, nails and a healthy metabolism.
Anaemia occurs when there is not enough haemoglobin in the body and physical symptoms of an iron deficiency occur.
An iron deficiency anaemia can't develop overnight, it develops over a longer period of time. First, an iron deficiency develops, a stage in which iron storages are depleted, although general health is (not yet) impaired.
Actual iron deficiency anaemia, the condition in which the body doesn't have enough iron to make healthy red blood cells, can have a far greater impact on your health.
Most of the 3 to 4 grams of elemental iron in our body is found in the form of haemoglobin. The rest of the iron is stored in the liver, spleen and bone marrow or is found in myoglobin in muscle tissue.
Symptoms of iron deficiency and anaemia
During the early stages of iron deficiency there are usually no signs or symptoms of an iron deficiency. However, since iron plays a key role in transporting oxygen to the tissues of the body, an iron deficiency anaemia can be diagnosed by any of the following signs and symptoms:
- Feeling weak and tired
- Muscle weakness
- Difficulty maintaining the body temperature
- Decreased immune function
- Decreased work or school performance
- Difficulty exercising
- Concentration, learning and memory problems
- Slow cognitive and social development during childhood
- Chills, difficulties maintaining an adequate body temperature
- Changes in appetite
- Paleness or yellowing of the skin
- Shortness of breath and chest pain
- Abnormal heartbeat
- Signs of a hormonal imbalance
- Impaired immune function
- An inflamed tongue (glossitis)
Because of its important role in transporting oxygen, anaemic people can appear pale, weak or tired, get sick more easily and have great differences in their physical and mental performance.
Feeling tired can indicate an iron deficiency anaemia, but it doesn't have to be. A multitude of complaints, illnesses, poor nutrition and everyday stress can all contribute to fatigue.
What causes iron deficiency?
There are a variety of reasons for iron deficiency. Iron deficiency can be a sign of a more serious illness, or often an insufficient iron intake.
Increased iron requirement
- An iron deficiency can be caused by your body's increased need for iron. For example, adolescent girls and women of childbearing age often have an increased iron requirement due to the loss of blood during menstruation.
- Adult women also have much higher iron needs when they are pregnant than when they are not pregnant.
- Constant vigorous exercise can sometimes damage red blood cells.
Insufficient absorption of iron from food
- Vegetarians are particularly prone to iron deficiency because they have to rely on non-heme (plant-based) sources of iron, which are less easily absorbed by the body than animal iron sources. Because of the body's inability to effectively absorb plant-based iron, vegetarians have a higher incidence of iron deficiency and iron deficiency anaemia than meat eaters.
- Other influencing factors are other foods and nutrients that are ingested with iron and contribute to poor absorption. These are known as iron inhibitors. Some common iron inhibitors include: Grains, legumes, fibre, egg protein, minerals (such as calcium, zinc, copper and magnesium), coffee, tea, some herbs (including peppermint and chamomile) and cocoa.
- People who often take acid-binding agents (e.g. against heartburn) can develop an iron deficiency over time. These contain calcium, which can hinder the absorption of iron.
- Gastrointestinal complaints such as coeliac disease, Crohn's disease or ulcerative colitis can also reduce the absorption of iron from food.
Loss of iron through blood loss
- Blood loss during menstruation
- Frequent blood donations
- Other types of bleeding (e.g. gastrointestinal ulcers)
- Surgeries with high blood loss
- Dialysis treatment, as it removes iron from the body
Who needs more iron?
All human, animal and plant life need iron, and luckily, iron is found in most of the foods we eat, such as chicken, spinach, peas, hamburgers, seafood, muesli and more.
If iron is so abundant, why should anyone take iron or consider a diet higher in iron?
The body has an impressive system for maintaining the delicate balance that makes iron levels healthy. Namely, it stores iron so that it can be used whenever needed. This is often referred to as your “iron storage”.
If the iron intake is low or iron is used too quickly, iron storages can become depleted - a condition known as iron deficiency.
Symptoms of an iron deficiency include tiredness, chills, paleness and fatigue. Talk to your doctor if you think you may have an iron deficiency as it can be a sign of a more serious condition.
Certain groups of people may be at an increased risk of iron deficiency anaemia:
- Pregnant women
- Women of childbearing age
- Women during menstruation
- Older adults/seniors
- People with Coeliac disease
- People with Crohn's disease
- Female athletes
- Long distance runners
Recognizing iron deficiency
In fact, most people find out that they have an iron deficiency when they want to donate blood and the screening tests required by the blood donation service show low iron levels.
It is recommended that you have your blood tested regularly to see if you need to take more iron, especially if you are pregnant, a vegetarian or have indigestion.
Fortunately, an iron deficiency is usually easy to determine by doing a simple blood test at your doctor's office.
- A haematocrit test determines the percentage of red blood cells in the total volume of blood. When haemoglobin and haematocrit are both low, a patient is in the later stages of iron deficiency anaemia.
- Ferritin - The storage form of iron in the body in the serum
- Serum iron - The amount of iron in your blood
- Transferrin saturation - Transport protein for the iron in the blood
If you have common symptoms of an iron deficiency or iron deficiency anaemia, talk to your doctor or health care provider and ask for a blood test.
Recommended daily amount of iron
The amount of iron that a person needs every day to prevent an iron deficiency depends greatly on age and gender. Women need more iron than men because they lose a certain amount of iron with the blood each month during the normal menstrual cycle.
But around the puberty stage, when a woman starts her menstrual cycle, her daily iron requirement increases, but decreases again when she reaches menopause. Women between 19 and 50 need more iron than any other group - this lies at around 18 milligrams a day.
Men of the same age group need significantly less and are still at a lower risk of suffering from iron deficiency.
- Children 4 to 8 years old: 10 milligrams
- Children 9 to 13 years old: 8 milligrams
- Women 19 to 50 years of age: 18 milligrams
- Pregnant women: 27 milligrams
- Breastfeeding women: 10 milligrams
- Men between 19 and 50 years of age: 8 milligrams
Animal and plant-based iron in comparison
There are two main types of iron: Heme iron (from animal products) and non-heme iron (found in plant-based products). There are two things to keep in mind:
- Animal foods contain one type of iron, heme iron, which is easier to absorb than the non-heme iron found in plants.
- If you eat different types of foods, they can work together to either increase the body's ability to absorb iron or they can do the opposite and make it difficult to absorb iron from food.
The NIH estimates that Americans get about 10-15 percent of their iron intake from heme iron, with the remainder coming from non-heme iron. Since non-heme iron is less absorbable, this may be one reason why iron deficiency is so common.
If you are a vegetarian or vegan, you should make sure that you get enough iron. If this is not possible, iron pills or iron capsules should be considered.
It is known that the type of iron found in plant-based foods is not as absorbable as the iron found in animal foods. Iron from meat, poultry and fish (heme iron) is absorbed two to three times more efficiently than that of plants (non-heme iron).
Vegetarians and vegans, however, can rely on non-heme iron, which is less well metabolized. This means that many vegetarians can be diagnosed with an iron deficiency - despite the fact that they get enough (non-heme) iron in their diet.
The total iron intake from a vegetarian meal can reach the recommended amounts, but far less iron is absorbed than from diets that contain meat. Essentially, the iron is there, but the body is unable to absorb it effectively.
What increases or decreases the iron absorption?
The amount of iron absorbed by the body also depends on other foods eaten with the same meal. Foods like meat or fish that contain animal heme iron increase the body's ability to absorb the type of iron found in plants (non-heme iron).
Iron can be found in plant-based foods like spinach and beans, but when you consume these vegetables with animal sources of iron, your body can make better use of the iron.
Since foods containing vitamin C can also increase the absorption of non-heme iron, this is another way for vegetarians and vegans to replenish their iron storages.
Some foods and drinks also contain substances that hinder the body's ability to absorb iron. Foods that contain chemical compounds such as polyphenols, phytates or calcium make it difficult for the body to absorb and store iron. They can be found in tea, coffee, whole grains, legumes, nuts, seeds and dairy products.
Among the richest sources of heme iron in foods are lean meats (beef, lamb, pork, chicken and fish) and seafood.
Food sources that do not contain heme iron include dark green leafy vegetables, nuts, seeds, legumes, beans, molasses, whole grains, enriched grains, dried fruits, eggs, dairy products.
What are the best foods to prevent an iron deficiency?
Putting together the right foods for the best iron absorption may seem difficult. But if you eat a varied diet that contains a lot of whole foods, according to American dietary guidelines, the inhibition of iron absorption by these substances is usually not a problem.
1. Make sure you follow a varied, whole-food diet that contains good sources of iron, such as
- Meat products from animals fed with grass
- Organic free-range poultry
- Free range eggs
- Organic dairy products (preferably unpasteurized) such as raw milk
- Various types of fruits and vegetables
- Occasionally whole grains
2. Combine foods that help your body absorb iron better. For example, you can combine a naturally high vitamin C diet (like leafy greens or citrus fruits) with beans for better iron absorption, as vitamin C helps your body absorb the non-heme iron.
3. Include foods high in vitamin C in your diet to increase iron absorption. These foods include: Guavas, red and green bell peppers, kiwis, oranges, grapefruits, blueberries, all non-heme vegetables such as brussel sprouts or broccoli, melon and pea pods.
4. These are the top 12 natural iron food sources that can help prevent an iron deficiency.
- Beef liver
- White beans
- Spinach, cooked
- Kidney beans
- Beef (grass-fed)
- Black molasses
- Pumpkin seeds
Note that the recommended daily intake is different for each person (adult males need 8 milligrams per day and adult females before menopause need 18 milligrams).
Health benefits of iron
1. Prevents anaemia
Anaemia is caused by low levels of red blood cells and haemoglobin production. When you suffer from anaemia, very little oxygen reaches the cells in the body. Anaemia usually leads to a decrease in energy, but can also affect many parts of the body - from poor brain function to immune deficiencies.
The World Health Organization estimates that about half of the 1.62 billion cases of anaemia worldwide are due to an iron deficiency, while the other half are due to genetic factors.
According to the Department of Human Health at Virginia Polytechnic Institute and State University, anaemia develops when: … people ingest insufficient amounts of iron, the absorption or transportation is impaired, there are physiological losses in connection with chronological or childbearing age, or chronic blood loss as a consequence.
In adults, iron deficiency anaemia can have a number of negative consequences, including a decreased ability to work or exercise, impaired thermoregulation, immune dysfunction, gastrointestinal disorders, and neuro-cognitive impairments.
2. Increases the energy level
Iron helps ensure that enough oxygen is transported to the cells and thus supports sustained energy. It also supports enzymatic metabolic processes so that proteins can be digested and nutrients can be absorbed from the food. This is why an iron deficiency can lead to fatigue, difficulty in activity, and many other symptoms of listlessness.
Symptoms of an iron deficiency can also include poor concentration, mood swings and problems with muscle coordination. Iron is necessary for the movement of the muscles because it stores oxygen in the muscles, which allows them to move and become stronger.
3. Supports the mental function
Iron is needed to support the brain function as it supplies the brain with oxygen. In fact, the brain uses over 20 percent of all oxygen in the body. Therefore, an iron deficiency can reduce memory and other mental functions.
In infants and children, an iron deficiency can lead to psychomotor and cognitive abnormalities, which can also result in learning difficulties.
4. Supports the development and growth
An iron deficiency can delay both normal motor functions, for example the ability to link thoughts with actions and movements, and mental functions such as learning and processing new information.
5. Necessary for a healthy pregnancy
An iron deficiency during pregnancy increases the risk of premature birth and also of the newborn being underweight. Sadly, premature babies are known to be more vulnerable to health in the first few years of their life. They can also delay growth and cognitive development.
All pregnant women are advised to consume plenty of foods and supplements rich in iron because the NIH warned that an inadequate iron intake during pregnancy increases the risk of an iron deficiency anaemia in women.
An insufficient iron intake also increases the risk of low birth weight, premature birth, low iron reserves and impaired cognitive and behavioural development.
A study by the Nutrition for Health and Development division of the World Health Organization found that if you take an iron supplement during pregnancy, the risk of low birth weight was only at 8.4 percent, as opposed to a 10.2 percent risk in women who did not take extra iron.
The average birth weight of infants born to mothers who took iron during their pregnancy was 31 g higher than that of newborns whose mothers did not take iron during pregnancy.
6. Supports the immune system
Iron, because of its role in metabolism, is necessary for a normal digestion and absorption of other nutrients from food. In addition to this, iron helps transport enough amounts of oxygen to damaged areas of the body, including injured tissues, organs and cells that are prone to infection or developing diseases.
7. Supports a positive mood
The function of the neurotransmitters, which support the positive mood, depend on a sufficient level of iron in the blood. Your mood depends on the balance of hormones - including serotonin, dopamine and other critical hormones – which can't normally be synthesized when the oxygen levels in the brain are low.
This is one reason why an iron deficiency leads to bad moods, poor sleep, low energy levels and a lack of motivation. If someone experiences changes in their mood and a feeling of a mild depression or anxiety, an iron deficiency could be one of the causes.
8. Prevents Restless Leg Syndrome
Iron deficiency is the most common cause of restless leg syndrome, which can lead to massive sleep disorders. Iron helps carry enough oxygen to muscles, which reduces muscle cramps and pain.
Iron deficiency in children
Toddlers need more iron than older children, as iron supports the growth process and cognitive development. It can be difficult for toddlers to get enough iron from their diet alone, especially if they don't eat everything. A blood test during the annual check-up can detect an iron deficiency early on before it becomes a major problem.
Iron deficiency in children most commonly occurs between the ages of six months to three years, which is due to rapid growth and insufficient intake of iron from food.
Infants and children are at a higher risk of an iron deficiency if they were born small or prematurely, were given cow's milk before their first birthday, were bottle-fed and not breastfed or were given more than 0.7 litres of cow, goat or soy milk a day.
Breast milk is believed to be high in bioavailable iron, but in amounts that unfortunately are not enough to meet the needs of infants older than 4 to 6 months. Therefore, the NIH recommends, that as soon as babies are able to, they should eat solid foods which are rich in bioavailable iron or meals and baby food fortified in iron.
Iron for athletes
You may be surprised to learn that an iron deficiency is a common problem faced by athletes and runners. One of the most important functions of iron is to carry oxygen to the cells in your body, so iron is essential for athletic performance.
Endurance sports and strength training stimulate an increase in the production of red blood cells, which increases the body's demand for iron. Athletes who are particularly prone to iron deficiency include: female athletes, endurance athletes and vegetarian athletes.
Why are female athletes prone to iron deficiency?
Because of the blood loss associated with menstruation, female athletes are particularly prone to iron deficiency. An active, female athlete with a rigorous exercise regimen is at an increased risk of iron deficiency anaemia. Iron deficiency is common - with or without anaemia - and reduces athletic performance.
Young female athletes are particularly prone to iron deficiency. Female athletes between the ages of 13 and 19 can have an iron deficiency due to menstruation and strenuous exercise. Female athletes who exercise intensely have a high incidence of amenorrhoea (the absence of regular monthly periods) which allows the body to maintain its iron storages.
Iron for endurance athletes
Male and female endurance athletes can also be at an increased risk of iron deficiency. In endurance athletes, what is known as a "foot strike" can damage red blood cells in the feet (from running in bad shoes on hard surfaces), which can lead to a loss in iron. Therefore, people who exercise regularly and intensely can have a 30 % greater iron need.
Vegetarian athletes also have a high level of iron deficiency. Vegetarians and people who avoid red meat often find it difficult to meet their body’s iron needs because they rely on non-heme iron (iron found in plants rather than animal products), which is less easily absorbed by the body .
Non-heme iron is found in dark green leafy vegetables, nuts, seeds, legumes, whole grains, fortified cereals, dried fruits, eggs, dairy products and molasses. Meanwhile, heme iron can be found in animal products such as beef, lamb, pork, chicken and fish and is absorbed by the body more easily.
If you are an athlete, or currently exercising, you should consider taking iron supplements. Ask your doctor to clarify whether you have an iron deficiency and whether or not an iron supplementation would be beneficial for your overall health and exercise program.
Iron and the period
About one in five women of childbearing age has iron deficiency anaemia. Women in this large age group (ages 12 to 49 years old) are at an increased risk of developing iron deficiency anaemia for two main reasons:
1. Blood loss during menstruation
2. Increased iron requirement during pregnancy.
Therefore, the daily requirement of iron that is ingested through food is greater than that of older women.
Women of childbearing age need more iron
Iron is important for the functioning and synthesis (production) of haemoglobin, a protein that carries oxygen through the body. Iron is also involved in DNA synthesis, immune function, brain development and the synthesis of neurotransmitters and collagen.
Pregnant women need significantly more iron than women who are not pregnant to compensate for the iron needs of the growing fetus, the increased blood volume during pregnancy and the blood loss during delivery.
Not enough iron during pregnancy can increase the risk of premature birth or result in a low birth weight for the baby. That is why all women of childbearing age need sufficient amounts of iron to cover the additional requirement in the event of a planned or unplanned pregnancy.
Iron deficiency in women of childbearing age
There are several factors that contribute to an increased risk of iron deficiency in women of childbearing age:
For example, excessive menstrual blood loss, which is estimated to affect 10% of American women, is a major risk factor.
Women of this age group with several children also show an increased risk of developing an iron deficiency anaemia.
Also, a previous iron deficiency anaemia and a low dietary iron intake can increase the risk.
Because adolescent girls and women of childbearing age are at an increased risk of developing an iron deficiency anaemia, experts recommend increasing their intake of iron-rich foods as well as foods that reduce the absorption of iron from plant-based foods (such as fortified grains and bread).
Combining plant-based sources of iron (such as spinach or peas) and foods rich in vitamin C (e.g. a glass of orange juice) with sources of heme iron (from meat, fish and poultry) increase the absorption of non-heme iron.
In addition to this, girls and women of childbearing age should be checked for anaemia every 5-10 years. Those with anaemia may need additional iron to bring their iron levels back to normal.
Iron during pregnancy
Iron is especially important during pregnancy as it is needed twice as much to care for both the mother and child. Pregnant women need more iron than non-pregnant women to compensate for the greatly increased blood volume, to meet the needs of the baby and to prepare the body for childbirth.
According to the Center for Disease Control and Prevention (CDC), 9% of women of childbearing age between 12-49 years are already affected by iron deficiency. Women with iron deficiency anaemia during the first two trimesters of pregnancy are two times more likely to have a premature birth and three times more likely to have a baby with a low birth weight.
Who is at risk from iron deficiency anaemia during pregnancy? During the early years of childbearing age, adolescents have a particularly high need for iron because of their rapid growth. Girls in particular have a higher need due to the loss of iron through menstrual bleeding.
Additionally, an estimated 10% of women in the United States have profuse blood drainage. If you have had heavy or too frequent periods in the past, you may be at an increased risk of developing an iron deficiency anaemia during pregnancy.
In addition to heavy periods, there are other factors that increase the risk of developing iron deficiency anaemia during pregnancy.
These factors include:
- Low dietary iron intake
- History of iron deficiency anaemia
- Pregnancies that follow closely in time
- Heavy periods after pregnancy
- Use of urinary catheters or other intrauterine devices
- Multiple births (twins, triplets or more)
Conversely, oral contraception is associated with a reduced risk of iron deficiency.
Iron for pregnant women and women who want to get pregnant
It is essential for the health of both mother and child that pregnant mothers meet their iron needs. This is why most prenatal supplements contain iron.
And because several factors increase a woman's risk of developing an iron deficiency anaemia, girls and women of childbearing age should consume foods rich in iron and combine plant-based sources of iron with vitamin C to increase absorption. If you are in doubt as to whether you are getting enough iron from your diet, talk to your doctor about the best way to supplement your iron level.
In addition to focusing on iron in your diet during the childbearing years, women who are or have been pregnant should get regular check-ups for iron deficiency anaemia and talk to their doctor about taking iron-containing supplements.
According to the CDC, pregnant women who do not supplement iron often have a hard time keeping their iron reserves high, especially during the second and third trimesters. Therefore, iron pills or iron capsules are usually recommended during pregnancy.
Iron for vegetarians
Compared to meat eaters, vegetarians and vegans often have greater difficulties in meeting the body's own iron requirements because the iron in plant-based foods can't be absorbed as efficiently as iron from meat. Because of the body's inability to effectively absorb plant-based iron, vegetarians have a higher incidence of iron deficiency and iron deficiency anaemia than non-vegetarians.
Should Vegetarians and Vegans Take Iron Supplements?
The National Institute of Health advises that strict vegetarians (those who do not consume any animal products) need to eat twice as much dietary iron as meat eaters. This is due to the lower rate of absorption of non-heme iron from plant foods.
For this reason, many doctors recommend iron supplements for vegetarians - especially athletes or girls and women (they all naturally have a higher risk of iron deficiency).
If you are a vegetarian or vegan, or if you strictly limit your red meat consumption, discuss your iron supplementation with your doctor.
Iron for seniors
The mineral iron found in a wide variety of foods is important for good health. Although seniors typically get enough iron in their diet to meet the recommended iron levels, there are other factors that can contribute to iron deficiency anaemia in this group.
Although we store some iron in our body, a low dietary iron intake can lead to iron deficiency anaemia over time. Symptoms of iron deficiency anaemia include feeling tired, weak or cold, suffering from decreased energy levels, shortness of breath, irritability, dizziness, immune deficiency and impaired mental functions.
In addition to the typical symptoms associated with iron deficiency, seniors with anaemia may experience more severe complications, including decreased physical strength and an increased risk of falling.
Risk factors for iron deficiency anaemia in old age
Although ageing does not lead to an increased need for iron in itself (in fact, we need less iron once we turn 50), the following factors can increase the risk of developing an iron deficiency with age:
Iron is important for the elderly and even mild iron deficiency without anaemia can lead to noticeable symptoms. Anyone who thinks they have symptoms of iron deficiency anaemia should speak with their doctor.
Can you get rid of an iron deficiency with iron capsules or iron pills?
High doses of extra iron (45 milligrams a day or more) can also cause side effects such as nausea, vomiting, cramps and constipation.
Iron in moderate amounts is considered to be well tolerated and usually does not lead to any side effects.
You should keep in mind that iron can interact with other nutrients, including calcium. Some studies suggest that calcium could affect the absorption of iron, although this effect has not been proven. Experts also recommend taking calcium and iron supplements separately, spread out over the course of a day, in order to achieve the greatest effect of both supplements.
The addition of iron supplements by people taking medication for Parkinson's, cancer or heart disease can worsen the absorption of the medication. Anyone taking medication should consult a doctor before taking iron pills or iron capsules.