Iron

FNH Nutrition

PateIron

Daily Requirement

Women                                         18mg

Men                                                8mg

Infants 0-6 months               0.27mg

6 months – 1yr                            11mg

Children 1-3yr                             7mg

                4-8yr                           10mg

               9-13yr                            8mg

The daily requirement of iron is higher for women due to menstruation. Post menopause men and women have the same iron requirements. Boys aged 14-18 have a slightly higher iron RDI of 11mg.

Reasons For Iron Deficiency

Iron deficiency is most often due to inadequate dietary intake, especially with;

  • Infants and young children (6 months to 4 years), because of low iron content in breast milk and other preferred foods, rapid growth rate and insufficient body reserves of iron to meet needs beyond about 6 months
  • Adolescents in their early growth spurt, because of rapid growth and the needs of expanding red blood cell mass
  • Females during reproductive years due to menstrual blood loss
  • Pregnant women, because of expanding blood volume, the demands of the foetus and placenta and blood loss post childbirth
  • Diets – Vegetarian, vegan and calorie restricted diets

Conditions associated with increased iron loss

  • Haemorrhage
  • Renal disease
  • Renal replacement therapy
  • Decreased (faster than normal) gastrointestinal transit time – e.g. chronic diarrhoea
  • Steatorrhea
  • Parasites
  • Internal bleeding – usually intestinal

Inadequate Iron absorption

  • Hypochlorhydria – low stomach acid
  • Crohn’s disease
  • Coeliac disease

Symptoms of Iron deficiency

Children

  • Pallor (paleness)
  • Listlessness
  • Behavioural disturbances
  • Impaired performance in some cognitive tasks
  • Some irreversible impairment of learning ability
  • Short attention span

Adults

  • Pallor
  • Low energy
  • Poor concentration

Iron, GABA & Dopamine

  • Iron deficiency may impair the degradation of y-aminobutyric acid (GABA), an inhibitory neurotransmitter in the brain, or may inhibit dopamine producing neurons. Dopamine is an important neurotransmitter in learning and memory and reward motivated behaviour.

Sources of Iron

There are two types of iron Fe 2+ (heme) and Fe3+ (non heme). Heme iron is Fe2+ attached to an organic compound such as haemoglobin, which we only get from meat.  Non-heme is primarily from plant foods. Although many vegetables have a high iron content, the non heme form is not as well absorbed and vegetarians may suffer from iron deficiency.

Absorption of Iron

The first step of absorption is breaking down foods so that the iron component can be isolated. This is done by chewing, saliva, stomach acid and digestive enzymes.

Vegetarian Iron

Non heme iron = Fe3+ = Ferric iron

This Fe3+ must be converted to Fe2+ in order to be absorbed into the blood stream.

Enhancing Fe3+ to Fe2+

  • Stomach Acid
  • Reductases (enzymes on the brush border of small intestine)
  • Ligands
  • Chelators
  • Vitamin C
  • Fructose
  • Citric Acid
  • lactic Acid
  • Tartaric Acid
  • Mucin – Synthesised by the body

Iron absorption

Is also enhanced if iron levels are low, improving absorption from 10% to 35%, this is mainly achieved by increasing the number of transport proteins on the brush border (of the small intestine) and therefore the transport of iron into the cells.

Cofactors

Other nutrients that help with iron storage and transport into and around the body are vitamins B2, B3, C and copper.

Inhibitors of Ferric Iron Fe3+ to Ferrous Iron Fe2+ include;

(The percentage following each substance indicates the possible extent of inhibition.)

  • Polyphenols, including tannins found in many teas (60%) and coffee (40%).
  • Oxalic acid, found in spinach, chard, berries, chocolate and tea.
  • Phytates, in maize, wholegrains, nuts and legumes. Phytates are water soluble and therefore are removed by soaking for 6-12 hours before consumption.
  • Phosvitin, found in egg yolk.
  • Nutrients such as calcium (inhibit by 70%), zinc ((inhibit by 70%), manganese ((inhibit by 30%), nickel and chromium.

Heme Iron Foods

All liver and organ meats    –    44-11mg

Oysters                                            9 mg

Mussels                                           6 mg 

Beef steak                                       5 mg

Anchovy                                         4 mg

Sardine, goat, lamb                      3 mg 

Crab, Turkey, mackerel            2.5 mg

Bass, pork, dark chicken            2 mg

Chicken, tuna, herring             1.5 mg

Non Heme Iron Foods

Chlorella                                130 mg

Spirulina                                 28 mg

Parsley                                      11 mg

Lentils, dried                            8 mg

Cashew nuts                             6 mg

Sundried tomato                     6 mg

Tahini, sesame seeds              5 mg

Sunflower seeds                      5 mg

Pine nuts                                  4 mg

Rye flour                                  4 mg

Almond                                    4 mg

Silverbeet                               3.5 mg

Rolled oats raw                     3.5 mg

Pistachio                                  3 mg

Dried apricots                         3 mg

Wholemeal wheat flour        3 mg

Puffed millet                            3 mg

Quinoa, boiled                        3 mg