What role does iron play in our bodies, and why is it so important?

Iron is an important dietary mineral which transports oxygen around the body and is responsible for making haemoglobin (Hb) which is found in red blood cells. This is essential for providing energy for daily activity and life.Some additional roles of iron include:

  • Oxygen transport– red blood cells contain haemoglobin, a complex protein that carries oxygen from the lungs to the rest of the body. 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 our muscle, plus provide oxygen to them to assist with energy production.
  • Enzymes– many enzymes throughout the body contain iron, including those involved in energy production. Enzymes are important as they act as catalysts for many cell functions.
  • Immune system– proper functioning of the immune system relies, in part, on sufficient amounts of iron.

What happens when we become low in iron? What are some of the main symptoms?

Iron deficiency is caused by a depletion of iron stores which may result in a decrease in the levels of haemoglobin in the blood. Low iron levels may lead to a condition called iron deficiency anaemia, which is a result of low ferritin levels. Common symptoms of iron deficiency anaemia include:

  • Tiredness
  • Breathlessness even when you’re not exerting yourself
  • Loss of appetite and headaches
  • Pale complexion
  • Heart palpitations
  • Lack of concentration
  • Increased risk of infection
  • Weakness/dizziness

Which animal and plant-based foods are rich in iron?

There are two types of dietary iron:

  1. Haem iron – found in animal foods only. Rich sources of this type of iron include: Red meat (beef, kangaroo, lamb), offal, turkey, chicken, shellfish, salmon, tuna
  2. Non-haem iron – is found in eggs and plant foods. Rich sources of this type of iron include: whole eggs (iron is found in the yolk), legumes, lentils, spinach, pumpkin seeds, nuts, quinoa, amaranth, broccoli, tofu, raw cacao or dark chocolate, wholegrains, oats

How much of these do we need to eat to get our RDI?

The recommended dietary intake (RDI) for iron is different for different population groups. An outline of these can be seen below:

Age RDI
 All 1-3 years 9mg per day
 All 4-8 10mg per day
 Girls 9-13 8mg per day
 Girls 14–18 15mg per day
 Boys 9-13 8mg per day
 Boys 14–18 11mg per day
 Females 19–50 18mg per day
 Female 51+ 8mg per day
 Males 19+ 8mg per day
 All pregnant women 27mg per day
 Lactating women, 14–18 years 10mg per day
 Lactating women, 19–30 9mg per day

In most cases, it is quite easy to meet your RDI for iron. Some examples of foods and their iron content are as follows:

Haem iron sources:

  • 100g chicken liver = 11mg
  • 100g beef steak = 3.5mg
  • 100g kangaroo meat = 3.2mg
  • 100g salmon fillet = 1.28mg
  • 100g chicken breast = 0.4mg

Non-haem sources:

  • 30g Weetbix = 4.2mg
  • 1 cup lentils = 3.7mg
  • 1 cup kidney beans = 3.1mg
  • 100g tofu = 2.96mg
  • 1 cup cooked quinoa = 2.8mg
  • 1 cup chickpeas = 2.7mg
  • 1 cup cooked rolled oats = 1.3mg
  • 1 cup raw spinach = 1.2mg
  • 1 slice wholegrain bread = 0.8mg
  • 1 whole egg, boiled (45g) = 0.7mg

It’s also important to note that there are dietary factors that boost iron absorption and factors that reduce iron absorption:

Iron enhancers:

  • Vitamin C – foods rich in vitamin C can greatly boost the absorption of non-haem iron. Foods such as citrus fruits and juices, strawberries, kiwi fruit, pawpaw, melons, green leafy vegetables, capsicum, tomato and broccoli are great to add to meals to ensure the best uptake of iron.

Iron inhibitors:

  • Tannins in tea, coffee and wine reduce iron absorption by binding to the iron and transporting it out of the body.
  • Soy proteins can reduce absorption from plant sources.
  • Calcium and phosphorus reduce the absorption of plant-based sources of iron.
  • Phytates and fibres in wholegrains and legumes can reduce the absorption of iron and other minerals. This does not mean you shouldn’t consume them, it just means to be cautious as to how much you consume.

At what point should we see a doctor and/or supplement with iron?

If you have been complaining about tiredness and/or fatigue for a while or have been expressing any of the symptoms mentioned above, then it could be worth your while to see your GP and get some general bloods done and investigate your iron levels.

A dietitian and/or GP can interpret your bloods and inform you whether your levels warrant supplementation. Some population groups who may require an iron supplementation due to being a risk for iron deficiency include:

  • Teenage girls
  • Menstruating women, particularly those with heavy periods
  • Vegetarians and vegans
  • Athletes, particularly female athletes
  • Those with inflammatory bowel disease or coeliac disease
  • Regular blood donors
  • Those with chronic diseases such as cancer, kidney disease, heart failure, autoimmune diseases
  • Alcoholics
  • People with poor diets, restricted diets or following fad diets