Essential Vitamins & Minerals /

Iron

01 In Brief

Iron requirements increase by 50 per cent during pregnancy. Iron is the only mineral where a diet high in iron is sufficient to meet this increase in demand from otherwise healthy women.

Routine iron supplementation in low risk women is not automatically advised in Australia.

High risk women are those who: are found to be iron deficient at their first antenatal visit; have a poor dietary intake of iron; have a multiple pregnancy; have had a recent pregnancy; are currently breast feeding; and who are vegetarians.

02 What Do I Need To Know?

• Iron is a mineral that is required to make haemoglobin, which transports oxygen to all parts of the body. Iron deficiency affects all iron-dependent cells, especially muscle and the neurotransmitters in the brain. Deficiency results in anaemia, tiredness, decreased immunity and may affect thinking and behaviour.
•  Dietary sources of Iron are from two groups: 
  • Haem sources
    • Meat, chicken, fish, 
  • Non Haem or plant sources
  •  Legumes, nuts (pine nuts and cashews), seeds (sunflower and sesame seeds), dried fruits (dried apricots and prunes), whole grains, green leafy vegetables; 
  • Fortified foods (cereals, drink mixtures e.g. Milo and Ovaltine) contain non haem iron.
• Haem sources of iron are well absorbed while non Haem sources are not as well absorbed. However, non Haem sources become more easily absorbed when eaten with animal protein meat and foods rich in vitamin C such as citrus fruits, strawberries, tomato and capsicum.
• Liver is a good source of iron but because it contains high levels of Vitamin A it should be limited to 50g per week. Pâté should be avoided because of the risk of infection from listeria. Find out more from Flourish Foods and Toxins to Avoid.

 IRON IN PREGNANCY

• During pregnancy the recommended daily intake of iron increases from 18mg per day to 27mg per day. This is due to an increase in the mother's blood volume, demands of the growing fetus and placenta, blood loss at delivery and lactation.
• Although healthy adults absorb only 10-15 per cent of dietary iron, during pregnancy there is a physiological increase in iron absorption.
•  Iron absorption from diet or supplements is decreased by: 
  • Drinking tea or coffee;
  • Taking supplements with a meal of milk, cheese or yoghurt;
  • Unprocessed bran;
  • Taking zinc and calcium supplements at the same time.
• Tests used to check iron status are Haemoglobin (Hb) and Ferritin. 
  • Hb level in the range of 105-115 is considered borderline and below 105 is considered anaemic. 
  • Ferritin level of less than 50 is considered low and below 12-15 suggests depleted stores. Tests must be interpreted with care as many other factors affect ferritin levels, such as a reduction in ferratin as a result of higher blood volumes in pregnancy, diurnal and day-to-day variations, and when a person is sick or has consumed alcohol it may be falsely elevated.
• Iron deficiency in pregnancy is associated with low birth weight and prematurity. Twenty per cent of women entering pregnancy have low iron stores. Iron status is usually checked at the start of, and during pregnancy.

SUPPLEMENTATION OF IRON IN PREGNANCY

• Routine supplement of iron is currently not recommended, as there is insufficient evidence of significant improvement in the mother's or fetal health.
• However, supplements are recommended in high risk groups such as:
  • Iron-deficient mothers at their first antenatal visit, with borderline or deficient results;
  • Poor dietary intake of iron;
  • Multiple pregnancy;
  • A recent pregnancy;
  • Breast feeding; and
  • Some vegetarians.
• Iron supplementation in pregnancy is beneficial in preventing iron deficiency in the infant's first year of life. In children, iron deficiency has been associated with developmental delay and behavioural problems such as ADHD.
• Some women experience unwanted side effects from iron especially gastrointestinal upsets. In some people with high iron loads, supplementation may be harmful, particularly if they have a disease associated with a high iron load, such as haemochromatosis. Check with your doctor first.
• The dose of supplemental iron is usually individually tailored for most pregnant women. In some countries it is given routinely (e.g. USA and Denmark) from the first antenatal visit. There is evidence that a low dose of iron of 20-30mg per day is effective in borderline deficiency and a dose of 60mg is effective for women with depleted stores. Iron is available in two forms, ferric and ferrous salts. Ferrous iron is better absorbed, however, various ferrous iron salts contain different amounts of elemental iron, which is the amount of iron available for absorption. For example ferrous sulphate contains 300mg of total iron and only 60mg of elemental iron. Your doctor will be able to advise which supplements are appropriate for your individual circumstance.
• As it often takes up to 6-12 months for iron supplementation to restore stores, iron supplements should be taken with a diet high in iron-rich foods and vitamin C.
• As the dose of iron increases the absorption decreases, so a high dose is better taken divided into two doses.
• There is some evidence that zinc absorption is decreased by high dose iron supplementation and additional supplements may need to be considered if iron supplements are used. This occurs when iron is taken without food however the effect when taken with food is not significant. 

03 What Others Say

•  Royal Women's Hospital Fact Sheet 

Iron in pregnancy RWH

04 I Want To Know More

• Cochrane Review - Effects and safety of preventive oral supplementation with iron or iron and folic acid for women during pregnancy. Peña-Rosas JP, Viteri FE This version first published online: July 19. 2006

Cochrane review on safety of iron in pregnancy

• National Institute of Health - excellent article from US about iron supplements 

NIH Dietary Supplement fact sheet - iron

• Effects of prenatal iron supplements on zinc absorption - Journal of Nutrition 2000; 130: 2251-2255

Effects on Zinc Absorption

• Pregnancy and the vegan diet 

Vegan diet and iron

05 Clinicians Tools and Resources

• Table of iron-rich foods from the RWH Melbourne

Iron-rich foods RWH

Last updated: 12/07/2011 by Dr Elizabeth Hallam*/Claire Galea

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