Glossary Detail

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name of the term: Iron

Short introduction

  • Iron is a trace element with the symbol Fe.
  • Most of the body’s iron is found in red blood cells (in haemoglobin). It gives blood its red colour.

Main natural sources

  • Food contains 2 types of iron: haem and non-haem iron. Haem iron is a part of haemoglobin and myoglobin so found only in animal tissue.
  • Meat, poultry and fish contain 40 percent haem iron and 60 percent non-haem iron.
  • Non-haem iron is found primarily in plant sources: dried beans, peas, lentils, vegetables (spinach) and (fortified) grain products. It is also found in animal sources such as egg yolk and dairy products.
  • The body absorbs haem iron better than non-haem iron.
  • Enhancers and inhibitors present in the same meal influence absorption of non-haem iron. Enhancers include vitamin C and red meat, poultry and seafood. Inhibitors include phytic acid/phytate (legumes, grains, rice), egg protein, soy protein, coffee and tea. Particular minerals, such as calcium and magnesium, can inhibit the absorption of both haem and non-haem iron. However, the effects of enhancers and inhibitors of iron absorption are reduced by a typical mixed western diet and have little effect on the iron status of most people.
  • Breast milk is low in iron but it is well absorbed; after birth, iron stores are sufficient for the first 4 to 6 months of life.

Main function

  • Essential component of hundreds of proteins and enzymes.
  • Component of haemoglobin, a protein that transfers oxygen from the lungs to the tissues.
  • Component of myoglobin, a protein that provides oxygen to the muscles.
  • Found in proteins involved in brain development and function. Involved in synthesis of myelin (proper conduction of nerve impulses) and neurotransmitters (brain chemicals that communicate information throughout brain and body), for example.
  • Needed for growth and development, normal cell functioning and synthesis of some hormones, for example.

Deficiency disease

  • The terms iron deficiency (ID), iron deficiency anaemia (IDA) and anaemia are often used interchangeably. Deficiency ranges from depleted iron stores (without health impairment) to iron deficiency with anaemia (inadequate iron to support red blood cell formation affecting the functioning of several organ systems). When iron reserves in the body are depleted, anaemia develops. It is considered a nutritional deficiency of public health significance: it is seen all over the world and has serious consequences.
  • It develops gradually. In the beginning there may be no symptoms or signs may be mild.
  • It can affect growth and may lead to long-term altered behavioural and neural development.
  • Studies in infants suggest that some of these effects may be irreversible.
  • Infants are at particular risk due to their rapid growth and limited dietary sources of iron.
  • Follow-up studies from preschool age to adolescence report poorer cognitive, motor, and social-emotional function, as well as persisting neurophysiologic differences.

Recommended daily intake

Latest Dietary Reference Intakes  (DRIs) 
Institute of Medicine (IOM)

Age categoraPer day

Pregnancy27 mg (RDA)
Lactation
14 – 18 years
19 – 50 years
10 mg (RDA)
9 mg (RDA)
Infants 6 – 12 months11 mg (RDA)
Children
 1 – 3 years
 4 – 8 years
7 mg (RDA)
10 mg (RDA)
Males
 9 – 13 years
14 – 18 years
19 – 30 years
31 – 50 years
50 – 70 years
> 70 years
8 mg (RDA)
11 mg (RDA)
8 mg (RDA)
8 mg (RDA)
8 mg (RDA)
8 mg (RDA)
Females
 9 – 13 years
14 – 18 years
19 – 30 years
31 – 50 years
50 – 70 years
> 70 years
8 mg (RDA)
15 mg (RDA)
18 mg (RDA)
18 mg (RDA)
8 mg (RDA)
8 mg (RDA)

 

RDA = Recommended Dietary Allowance.


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