WHAT IS IRON?
Iron is a micromineral (or trace element) that supports the production of haemoglobin (a protein in red blood cells that transports oxygen around the body). In this article I will be providing a full overview of this important nutrient.
WHEN WAS IRON DISCOVERED?
Awareness of iron dates back to around 3400 B.C. when the Ancient Egyptians are believed to have used iron found in meteorites to create tools and jewellery. However, exact details regarding the discovery of iron are unknown.
HOW DOES YOUR BODY USE IRON?
An average adult stores 3-4g of iron in their bodies. It can be found in every cell of the body but the majority (around 2.5g) is stored in the haemoglobin. As discussed above, iron is essential for the proper formation of haemoglobin which means it has a direct impact on energy and oxygen distribution. The list below outlines some of the main functions of iron:
– Assisting in the production of adenosine triphosphate (ATP) which is essential for cellular energy and proper cell functioning.
– Assisting in the production of catalase which converts hydrogen peroxide (a harmful by-product of metabolism) into oxygen and water.
– Assisting in the production of cytochromes which transport electrons throughout the body.
– Assisting in the production of haemoglobin which ensures adequate amounts of oxygen are supplied to all the body’s cells.
– Assisting in the production of myoglobin which takes oxygen from haemoglobin and stores it in the tissues until needed.
– Supporting healthy brain development and function.
– Supporting a strong immune system by assisting in the production of antibodies (proteins that are used by the immune system to identify and neutralise foreign objects such as bacteria and viruses) and T cells (a type of white blood cell that attacks infections and helps build immunity).
HOW MUCH IRON DO YOU NEED?
Women require much more iron than men. This is mainly down to menstruation which causes a lot of iron to be lost in the blood. Women need to recoup this loss by consuming additional iron in their diet. Vegetarians are advised to consume more iron than non-vegetarians whilst women taking oral contraception are advised to consume less (because oral contraceptives reduce the amount of blood and iron lost during menstruation). In 2000 the Institute of Medicine at the National Academy of Sciences provided the following recommended daily allowances (RDAs) for iron in milligrams (mg):
Children:
– Children aged 0-6 months:- 0.27mg.
– Children aged 7-12 months:- 11mg.
– Children aged 1-3 years:- 7mg.
– Children aged 4-8 years:- 10mg.
– Children aged 9-13 years:- 8mg.
Men:
– Men aged 14-18 years:- 11mg.
– Men aged 19 years and older:- 8mg.
Women:
– Women aged 14-18 years:- 15mg.
– Women aged 19-50 years:- 18mg.
– Women aged 51 years and older:- 8mg.
– Pregnant women aged 14-50 years:- 27mg.
– Lactating women aged 14-18 years:- 10mg.
– Lactating women aged 19-50 years:- 9mg.
Vegetarians:
– Men following a vegetarian diet:- 26mg.
– Adolescent girls following a vegetarian diet:- 26mg.
– Pre-menopausal women following a vegetarian diet:- 33mg.
Women taking oral contraceptives:
– Adolescent girls taking oral contraceptives:- 11.4mg.
– Pre-menopausal women taking oral contraceptives:- 10.9mg.
WHICH FOODS CONTAIN IRON?
There are two main types of iron found in food; heme iron (which is found in animal flesh only) and non-heme iron (which is found in dairy products and plant foods). The list below contains a selection of the best food sources:
– Beef Fillet Steak:- 3.1mg per 100g.
– Brazil Nuts:- 2.43mg per 100g.
– Chicken Liver:- 6.9mg per 100g.
– Parsley:- 5.5mg per 100g.
– Pistachio Nuts:- 14mg per 100g.
– Spinach:- 6.7mg per 100g.
WHAT ARE THE SYMPTOMS OF GETTING TOO MUCH IRON?
Overdosing on iron from food alone is very difficult. However, since the body excretes very little iron (especially amongst men) overdosing through supplements is a much more common problem. Because of this the National Academy of Sciences set the following daily tolerable upper limits (TULs) for iron in 2001:
– Children aged 1-13 years:- 40mg.
– Adults aged 14 years and older:- 45mg.
Exceeding these TULs can lead to iron overdose. Regular blood transfusions and hemochromatosis (a metabolic disorder which causes iron to be deposited in the body’s tissues) also increase the risk of iron levels in your body becoming too high. On top of this recent research has suggested that men are at a slightly higher risk of iron overdose than women because they do not excrete any iron from their body. If iron levels in the body do become too high it can lead to the following negative symptoms:
– Bronze or grey coloured skin.
– Damage to the intestinal tract lining.
– Dizziness.
– Fatigue.
– Headaches.
– Liver failure.
– Loss of appetite.
– Nausea.
– Shortness of breath.
– Vomiting.
– Weight loss.
WHAT ARE THE SYMPTOMS OF NOT GETTING ENOUGH IRON?
Iron deficiency is one of the most common nutrient deficiencies in the world. It can be caused by many factors which include:
– Consuming high levels of caffeine, oxalates (which are found in certain vegetables), phosphates (which are found in carbonated drinks and processed foods), phytates (which are found in certain nuts and pulses) and tannins (which are found in tea).
– Donating blood regularly.
– Excessive menstrual bleeding.
– Infection.
– Medical conditions that cause internal bleeding.
– Nutrient deficiency (not getting enough copper, vitamin A or vitamin C can inhibit the absorption of iron).
– Poor dietary intake of iron.
Being deficient in iron has a number of adverse side effects. The most significant of these is the various types of anemia which inhibit the body’s ability to transport oxygen to the cells that need it. The main negative symptoms of iron deficiency are listed below:
– Depression.
– Dizziness.
– Fatigue.
– Hair loss.
– Headaches.
– Hypochromic anemia (a condition where the red blood cells become paler than normal due to a reduction in haemoglobin which causes the skin to look pale).
– Increased risk of infection.
– Loss of stamina.
– Microcytic anemia (a condition where the red blood cells become smaller than normal).
– Reduced concentration.
– Weakness.
IRON SUMMARY
As you can see iron is a highly important nutrient. Without it your body cannot form haemoglobin properly which has an adverse effect on both your energy levels and your ability to transport oxygen to different cells. On top of this iron deficiency is a very common problem so you need to make sure that you are eating enough and also that your body is storing enough. I hope this article helps you keep on top of your iron intake.
Now I want to hear your thoughts. Have you experienced any of the problems associated with iron deficiency? Does your diet contain adequate levels? Leave a comment and let me know.
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If you think you might be iron deficient, you can get your iron levels tested – you may be anemic. Your
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Sources:
Human Iron Metabolism (Wikipedia)
Iron (Chemistry Explained)
Iron (WHFoods)
Iron Food Data Chart (Healthy Eating Club)
Iron Information (Health Vitamins Guide)