What causes iron deficiency?

Iron is a mineral nutrient involved in many important functions in the body including providing energy for daily life. Iron deficiency affects roughly 1 billion people globally and the most common cause is the lack of iron in the body. It is thought that 8% of women and 3% of men in the UK population have iron deficiency anaemia. Many people don’t know they have iron-deficiency anaemia and may experience symptoms for years without knowing the cause. Let’s take a look at what causes iron deficiency, the symptoms and the treatments available.

📝 What are the roles of iron in the body?

Some of the many roles of iron in the body include:

• Transport oxygen around the body – Iron is needed to produce red blood cells which contain a protein called haemoglobin. This protein can carry oxygen from your lungs to all the cells in your body so they can work properly. Haemoglobin is partly made from iron and accounts for about two-thirds of the body’s iron
• Myoglobin – a special protein that helps store oxygen in muscle cells. Myoglobin contains iron and is responsible for the red colour of muscle
• Enzymes – many enzymes throughout the body contain iron, including those involved in energy production. Enzymes are catalysts (increase the rate of chemical reaction) that drive many cell functions
• Immune system– proper functioning of the immune system relies, in part, on sufficient iron. The immune system helps us fight infection

How does iron deficiency anaemia develop?

Eating iron-rich foods is the main source of iron in your body. Excess iron is stored in your body until it’s needed to make haemoglobin. Iron deficiency anaemia develops when your body uses the iron stores faster than they can be replenished, or for some reason, the flow of iron into your system has slowed. There are three stages to this process:

Stage 1

The supply of iron to make new haemoglobin and red blood cells is reducing but hasn’t yet affected your red blood cells.

Stage 2

At this stage iron stores are low and there is a change in the process of producing new red blood cells (erythropoiesis). You develop iron-deficient erythropoiesis and the bone marrow makes red blood cells without enough hemoglobin.

Stage 3

At this stage, there isn’t enough iron to make healthy red blood cells from haemoglobin. The concentration of haemoglobin reduces below the normal range causing iron deficiency anaemia and symptoms may appear.

🏥 What are the symptoms of iron deficiency?

If you have mild or moderate iron deficiency, you may not realise it as you may just feel tired and run down. Moderate to severe iron deficiency shows up with more obvious signs and symptoms:

• Fatigue and weakness
• Feeling lightheaded
• Shortness of breath
• Restless leg syndrome
• Pica (a condition in which people crave non-food items like ice, chalk, paint or clay)
• Cold hands and feet
• Fast heartbeat

🦠 What are the causes of iron deficiency?

Inadequate iron intake is the common cause of iron deficiency but there are many reasons that a person might become deficient in iron:

Blood loss

Chronic conditions that can cause internal bleeding can lead to iron deficiency anaemia. Stomach ulcer, polyps in the colon or intestines are some examples of these conditions.

Certain pain relievers, such as aspirin, can also lead to gastrointestinal bleeding in the stomach. Heavy periods, regular blood donation and nose bleeds can also be a cause of blood loss.

Low iron intake in the diet

The amount of iron in your diet is important. Insufficient iron levels in the body over a significant period can cause iron deficiency anaemia. Some studies suggest vegetarians or vegans are more at risk of iron deficiency anaemia because of the lack of meat in their diet.

Increased requirement for iron

Breastfeeding and pregnant women need more iron during this time to create enough oxygen for the baby. If this extra iron isn’t increased iron deficiency can quickly occur.

Health conditions

Some chronic diseases put individuals at increased risk of iron deficiency such as inflammatory bowel disease, celiac disease, Crohn’s disease, autoimmune diseases and kidney disease.

People with kidney disease do not make enough of a substance called erythropoietin. If the body can’t make enough erythropoietin to make red blood cells, iron levels can drop. Celiac disease and Crohn’s disease can make it harder for your intestines to absorb iron from the foods.

Excessive exercise

People who exercise excessively and athletes lose iron through their GI tracts and through the breakdown of red blood cells.

Problem with iron absorption

There are situations when people have problems with iron absorption including:

• A Helicobacter pylori infection of the stomach
• Gastrointestinal surgery, including weight loss surgery, prevents your body from absorbing enough iron. For example, people who’ve had gastric bypass surgery or a gastrectomy may develop iron deficiency anaemia
• Certain rare genetic conditions that disrupt the body’s ability to absorb iron

🩺 Complications of iron deficiency anemia

If left untreated, iron deficiency can lead to other health problems. These include:

Fast heartbeat

The heart has to pump more blood to compensate for the low amount of oxygen, resulting in an irregular heartbeat, chest pain or shortness of breath. In severe cases, it can lead to heart failure or an enlarged heart.

Pregnancy complications

In severe cases of iron deficiency, a child may be born prematurely or with a low birth weight. Most pregnant women take iron supplements as part of their prenatal care to prevent this from happening.

Delayed growth

Infants and young children who are severely low in iron may show stunted growth and delayed development. They may also be more prone to infections. Low-iron milk such as cow’s milk given before the age of one can also be a cause of low iron levels in this group.

🧪 Diagnosis of iron-deficiency anaemia

After taking a complete medical history and physical examination your healthcare provider will gather more information through blood tests. Here are some of the things that may be done:

• A complete blood count test (CBC test) that checks your red and white blood cells, platelets and other components
• Examination of red blood cells under a microscope. If red blood cells appear pale and smaller than usual this is a sign of anaemia
• Iron levels in the blood will be measured
• Transferrin levels in the blood will be measured. Transferrin is the protein that carries iron
• Ferritin levels in the blood will be measured. Ferritin is a protein that stores iron
• If appropriate a colonoscopy may be requested allowing a doctor to examine the lower portion of the large intestine. An upper GI endoscopy may be more appropriate allowing examination of the lining of the oesophagus, stomach, and upper part of the small intestine

💉 Treatment for iron deficiency

Treatment is determined by how severe the iron deficiency is, below are some typical treatment options:

Iron supplements

Iron tablets can help restore iron levels in your body. They are recommended to be taken on an empty stomach, which helps the body absorb them better, but If they upset your stomach you can take them with meals. You may need to take the supplements for 3-6 months. Iron supplements may cause side effects of constipation or black stools. In severe cases, patients may be prescribed intravenous (IV) iron supplements.

Blood transfusions

To treat serious cases of iron deficiency quickly blood transfusions may be needed to increase the amount of red blood cells and iron in your blood.

Change in diet

A simple way to improve iron levels is to increase dietary iron intake. the following foods are a good source of iron to consider:

• Iron-fortified cereals
• Red meat
• Dark green leafy vegetables
• Pulses and beans
• Eggs
• Dried fruit, such as dried apricots, prunes and raisins

Foods rich in Vitamin C are important to include in the diet when iron is low as it helps in iron absorption these include:

• Citrus foods such as oranges
• Strawberries
• Brussel sprouts
• Broccoli
• Blackcurrants
• Peppers

📝 Conclusion

Not eating enough iron-rich foods, blood loss due to menstrual period and inability to absorb iron are some of the main reasons for iron deficiency anaemia. It happens when your body doesn’t have enough iron. If you suspect you have an iron deficiency, see your healthcare provider for a blood test.

Sources

• Anaemia – iron deficiency | Health topics A to Z – CKS – NICE
• Iron deficiency anaemia – NHS
• Iron-Deficiency Anemia: Symptoms, Treatments & Causes
• Anemia of Inflammation or Chronic Disease – NIDDK