Facts
Why iron is good for you
Iron is required to carry oxygen in the blood. Every one of the red blood cells in the body contains a protein called haemoglobin (four atoms of iron are attached to every atom of haemoglobin molecule). In the lungs, oxygen molecules attach to the iron atoms and are carried to the blood cells. When the oxygen reaches its destination, it is swapped for the waste carbon monoxide and carried back to the lungs where it is removed by exhalation.
Important iron facts
- Iron is a trace minerals which means only very small amounts of this mineral are required to enable the proper functioning of the body
- Iron is the most abundant trace mineral in the body
- Iron comes in two categories: haeme iron, found in meat and non-haeme iron, found in plant foods.
- Haeme iron is much more easily absorbed from foods than non-haeme iron
- Non-haeme iron absorbed can be increased by eating even a small amount of food that has haeme iron in it
- Eating foods with vitamin C helps the body absorb more of the non-haem iron
- The iron content of vegetable foods can be increased by using cast-iron cookware
- Copper is vital for iron metabolism
- Iron is also found in some enzymes which are required for chemical processes in all parts of the body. Many enzymes that contain iron are needed for energy production
- Iron supplements (tablets or fluid) cause the stools to become quite darkened (almost black) and this is quite normal, as it is due to the natural red-black colour of the iron
- The amount of oxygen in the body determines how much oxygen gets to the rest of the body. Not enough iron and fewer red blood cells are made. Not enough red blood cells, then anaemia occurs – weak, tired, pale and short of breath
- Sometime the liquid form of iron can cause the teeth to become temporarily discoloured when it comes into contact with them. If this occurs, then just brush the teeth with bicarbonate of soda to remove the temporary stain. To prevent it from happening in the first place, mix the liquid iron supplement with juice or try to avoid contact with the teeth when drinking it
Iron works best with
Health
Iron and health
- Iron helps to treat iron-deficient anaemia
iron helps anaemia by increasing the number of red blood cells that are circulating in the blood and also in the stores of red blood cells. The condition anaemia occurs when there are low levels of iron in the blood. Iron is important as it is a key component of haemoglobin, which carries oxygen to every cell in the body. Anemia can be caused by a number of conditions, including loss of blood during heavy menstruation, pregnancy, blood donation, bleeding ulcers, as well bleeding during and after surgery - Iron is required for a healthy immune system
Iron is needed to maintain and regulate many of the functions of the immune system, to ensure it runs smoothly and prevents illness and infection. - Iron enables properly formed haemoglobin
Iron is a vital component of haemoglobin, the substance which carries oxygen to every single part of the body. Adequate iron intake ensures that haemoglobin is well formed and functioning properly - Iron is an oxygen carrier
Iron’s most important benefit is that it carries oxygen and helps to transfer that oxygen from one cell to another. This helps to ensure the cells can respirate and perform their functions normally. - Iron is needed for a healthy brain
The brain uses around 20% of the oxygen in the body. This means it is critical that the body has adequate levels of iron, to ensure the brain gets the level of oxygen it requires to function in a healthy way. - Menstrual problems – iron helps to replace the iron and blood lost when a woman has her periods, especially if she loses a lot of blood each menstrual cycle
People who wish to take an iron supplement should talk to a medical professional before taking it.
Deficiency
Groups at risk of iron deficiency
Iron deficiency is common, with at least 25% of the population being at risk of iron deficiency. The following are the groups who may be at a high risk of having an iron deficiency:
- Women and girls who are menstruating
Women and girls who are menstruating need more iron to replace that which has been lost during monthly menstruation. Women and girl who have heavy menstrual low and longer menstrual periods may be at a higher risk of iron deficiency due to the higher than normal blood loss each month. - Teenage girls
Teenage girls need extra iron to enable their continuous growth and development. - Babies and toddlers
Babies and toddlers need a lot of iron, due to their rapid growth and development and if they do not get enough iron, may fall behind in their mental development. - Women who are pregnant or breastfeeding
Women who are pregnant or breastfeeding need more iron to supply to their growing foetus or newborn child for their proper growth and development. - Athletes
Athletes may need extra iron because they are using more of it when they are exercising – it helps provide more oxygen to their cells to help with cell respiration and endurance. - People who are malnourished
People who are malnourished are not eating enough of any foods, so may become deficient not just in iron but in all the minerals and vitamins. - People under stress for a long period
People who experience long term stress may become deficient in iron, because their body uses the stores of iron for dealing with the stress (including all the tissues in the body affected by it) and especially the lack of cell respiration could result in anaemia. - People who have lost a lot of blood
People who have lost a great deal of blood through an accident or injury or even in surgery will need to have their blood loss reversed through supplementation, either intravenously (if it an acute deficiency) or through tablet / liquid supplementation. - Vegetarians or vegans
People who eat a predominantly vegetarian diet may become deficient in iron if they are not eating the plant foods rich in iron with foods rich in vitamin C. - People with anaemia
People who have the condition anaemia either do not have enough red blood cell, haemoglobin or stored red blood cells. Anaemia can be due to a variety of factors, but iron-deficient anaemia is directly due to a deficiency of iron in the diet.
People in these groups at risk of deficiency should talk to a medical professional about iron supplements before taking them.
Symptoms of iron deficiency
Iron deficiency causes the following symptoms:
- Anaemia
- Behavioural problems
- Breathing difficulties
- Fatigue
- Heart palpitations upon exertion
- Iron-deficient anaemia
- Irritability
- Memory and learning problems
- Pale skin, mucous membranes and nails
- Poor immunity
- Sore tongue
- Weakness
People who experience any of the symptoms above should seek the advice of their doctor about iron supplementation.
Food sources
Iron in food
| FOOD | AMOUNT | iron (mg) |
|---|---|---|
| Liver, chicken | 85g | 7.3 |
| White beans | 1 cup | 6.6 |
| Liver, beef | 85g | 5.8 |
| Oysters, raw | 6 medium | 5.6 |
| Black beans | 1 cup | 3.6 |
| Molasses, blackstrap | 1 Tbsp | 3.5 |
| Chickpeas | 1 cup | 3.2 |
| Kidney beans | 1 cup | 3.2 |
| Spinach, cooked | ½ cup | 3.2 |
| Prune Juice | 2/3 cup | 3.0 |
| Potato, baked | 85g | 2.7 |
| Barley | 1 cup | 2.1 |
| Raisins, seedless | 2/3 cup | 2.1 |
| Beef, mince | 85g | 1.8 |
| Lima beans | ½ cup | 1.8 |
| Wheatgerm | ¼ cup | 1.8 |
| Almonds, dry roasted | 30g | 1.1 |
| Chicken | 85g | 1.1 |
| Tomato juice | 1 cup | 1.1 |
| Bread, whole wheat | 1 slice | 0.9 |
| Brussels sprouts | ½ cup | 0.9 |
| Walnuts | 30g | 0.7 |
| Broccoli, cooked | ½ cup | 0.6 |
| Kale | ½ cup | 0.6 |
| Pecans | 30g | 0.6 |
| Strawberries | 1 cup | 0.6 |
| Peanut butter | 2 Tbsp | 0.5 |
| Tomato | 1 medium | 0.5 |
Daily intake
Iron recommended daily intake (RDI)
| RDA | lifestage | age | amount |
|---|---|---|---|
| INFANTS | 0-6mths 7-12mths |
0.27mg 1.1mg |
|
| CHILDREN | 1-3yrs 4-8yrs |
7mg 10mg |
|
| CHILDREN | 9-13yrs male: 14-18yrs female: 14-18yrs |
8mg 11mg 15mg |
|
| ADULTS | male: 19-50yrs female: 19-50yrs |
8mg 18mg |
|
| SENIORS | 51+yrs | 8mg | |
| PREGNANT | all ages | 27mg | |
| LACTATING | <18yrs 19-50yrs |
10mg 9mg |
|
| TOLERABLE UPPER LIMIT | lifestage | age | AMOUNT |
| INFANTS | 0-12mths | 40mg | |
| CHILDREN | 1-8yrs | 40mg | |
| CHILDREN | 9-13yrs 14-18yrs |
40mg 45mg |
|
| ADULTS | 19-50yrs | 45mg | |
| SENIORS | 51+yrs | 45mg | |
| PREGNANT | all ages | 45mg | |
| LACTATING | all ages | 45mg | |
| TOXIC LEVEL | >100mg | ||
The tolerable upper limits should only be taken for short periods and only under medical supervision.
Toxicity
Toxicity
Too much iron (>100mg) can be very toxic and in fact, lethal.
Iron supplements may be fatal for adults when taken in doses of 200-250 mg/kg per body weight.
Acute iron toxicity
Acute toxicity from taking too much in iron supplements – over 100mg can cause the following symptoms:
- Blood in stools *
- Congestion of blood vessels
- Fatigue
- Headache
- Increased pulse *
- Paleness
- Rapid increase in respiration and chest pain *
- If toxicity continues – coma and death within 6-8 hours
* People who experience the highlighted symptoms should seek immediate emergency treatment.
Chronic iron toxicity
Chronic toxicity of iron from taking higher than the therapeutic dose of supplements for a long time can cause the following symptoms:
- Abdominal pain
- Drowsiness
- Headache
- Throat pain
People who experience any of the above toxicity symptoms should discontinue their iron supplements and see their doctor for advice. Overdosage and toxicity is more likely to occur from taking too many supplements, whereas dietary intake of iron is highly unlikely to cause overdosage.
To reduce iron toxicity and its symptoms, supplement with the following:
Precautions
Precautions
Certain people should not take iron supplements at all:
- People with acute hepatitis
People with acute hepatitis (an acute or severe form of liver inflammation) irrespective of the cause should avoid iron supplementation because the excess iron levels can irritate the liver and cause it to be further inflammed, exacerbating symptoms.People with acute hepatitis (an acute or severe form of liver inflammation) irrespective of the cause should avoid iron supplementation because the excess iron levels can irritate the liver and cause it to be further inflammed, exacerbating symptoms. - People with haemosiderosis or haemochromatosis
People with any condition that causes an excessive accumulation of iron in the body (such as haemosiderosis or haemochromatosis) needs to avoid taking iron supplements, as they will only add to the high levels of iron in the body and possibly cause toxicity symptoms. - People with haemolytic anaemia
People with haemolytic anaemia have a condition where the red blood cells are being destroyed and adding an iron supplementation will only further exacerbate symptom, so should be avoided. - People that have had many blood transfusions
People that have had repeated blood transfusions have a weakened immune system and more fragile red blood cells, so should also avoid iron supplementation until their immune system is no longer compromised.
Certain people should not take iron supplements without first consulting their doctor for advice (to ensure iron supplementation does not conflict adversely with their condition):
- People who have any type of liver or kidney disease
- People with kidney or liver disease
- People with pancreatitis
- People with any type of intestinal disease
- People with any type of coronary artery disease
- People with excessive blood levels of vitamin C
- People with alcoholism
Interactions
Interactions with medications and supplements
The following are the medications and supplements that are more likely to cause a detrimental reaction with iron supplements:
- Allopurinol
Iron supplements are not recommended to be taken at the same time as the medication Allopurinol (used for conditions such as gout), as it may cause an excess amount of iron, more than is normal and healthy to be stored in the liver. - Antacids
People taking antacids should not take iron supplements at the same time, as the antacids will block the iron absorption and cause it to be poorly absorbed. - Cholestyramine
People taking Cholestyramine should not take iron supplements at the same time, as the Cholestyramine (used to lower cholesterol) will block the iron absorption and disable the effects of the iron. - Pancreatin
People taking Pancreatin should not take iron supplements at the same time, as the Pancreatin (used to improve the digestion of fatty foods) will decrease the iron absorption. - Penicillamine
People taking Penicillamine (used to treat active rheumatoid arthritis) should not take iron supplements, because the iron can decrease the effect of Penicillamine. - Sulfasalazine
People taking Sulfasalazine should not take iron supplements at the same time, as the Pancreatin (an anti-inflammatory agent in the treatment of inflammatory bowel and rheumatoid arthritis) will decrease the effect of the iron supplements. - Tetracyclines
People taking Tetracyclines (an antibiotic medication) should not take iron supplements at the same time, because the iron can decrease the effect of the Tetracyclines. It is recommended to take the iron 3 hours before or 2 hours after taking the Tetracycline medication, or start the iron supplement after completing the Tetracycline.
Beneficial interactions with iron
The following are the medications and supplements that are more likely to cause a beneficial (or neutral) reaction with iron supplements:
- Calcium
Calcium supplements, if taken at the same time as iron supplements, will decrease the absorption of the iron supplements unless vitamin C supplements are taken at the same time, to ensure the iron is properly absorbed. - Copper
Iron supplements help with the proper absorption of the copper supplements and should be taken together. - Vitamin C
Vitamin C is a good supplement to take at the same time as an iron supplement, as it helps the iron to be better absorbed. The vitamin C is vital for helping the iron make healthy red blood cells and haemoglobin. - Vitamin E
Vitamin E supplements will decrease the absorption of any iron supplements, so always take the iron with some vitamin C too. - Zinc
High levels of zinc supplements will decrease the absorption of any iron supplements, so always take the iron with some vitamin C supplements at the same time too.
References
References
- USDA National Nutrient Database – provides nutrient values for foods (accessed 5 January 2005)
- Osiecki, H. The Nutrient Bible. Bio-Concepts Publishing QLD, 2002
- Whitney EN, Cataldo DB, Rolfes SR. Understanding Normal and Clinical Nutrition, 6th Edition. Wadsworth/Thomson Learning, 2002
Last updated: 6 May 2024