Iron. The energy mineral.
has long been known to be important for red blood cell function
because of its fundmanetal role in the haemoglobin molecule.
Haemoglobin is the molecule that carries oxygen to the
tissues from the lungs and returns with carbon dioxide
from the cells. It is closely related to myoglobin, which
is responsible for energy production in the muscles.
iron is both plentiful and obtainable from a wide variety
of foods, iron deficiency is stillthe most common form
of mineral deficiency. In susceptible groups, such as the
elderly and teenage women, up to 50% of Americancs have
been found to be deficient in iron.
might expect, iron is mostly found in the tissues which
are involved in blood manufacture and blood cell breakdown,
namely the bone marrow, spleen and liver, as well as the
obvious iron content of the blood.
of dietary iron are available- haem iron and non-haem iron.
Haem iron (heme iron in the USA) is effectively animal
haemoglobin and is found abundantly in meat and animal
and liver, and is very well absorbed by the body. Non-haem
iron is the mineral form of iron and is found in plants.
Non-haem iron is poorly absorbed.
Functions of Iron in the body
- Main component of haemoglobin, which transports oxygen
and carbon dioxide to and from the lungs.
- Supports the action of many enzymes (especially for energy
- May have anti-cancer properties
- Powerful immune-system booster
Although iron is the second most abundant mineral on our
planet and is present in many food sources, iron deficiency
is still the most common mineral deficiency. Often this is
related to the many factors which either increase or decrease
iron absorption, as well as the absolute amount of iron in
As suggested above, the form in which iron is taken has
a significant effect on its bioavailability, and the haem-form
is much better absorbed and utilised by the body.
Many of the symptoms of iron deficiency are related to the
consequences of poor oxygen and carbon dioxide transport.
For example, children who are iron deficient may
have learning difficulties due to the fact that their brains are "starved"
(relatively speaking) of oxygen, which makes the brain less
efficient. Anaemia may lead to lack of exercise which, in
turn affects fitness and other body systems.
Women, and especially menstruating women are particularly
at risk of iron deficiency, due to their regular blood loss.
Other groups who are prone to iron deficiency include the
elderly, babies under 2 years of age, pregnant women and
teenagers (especially girls). Babies fed on formula absorb
less of the available iron than breast-fed babies.
Iron deficiency can cause significant drops in work capacity,
which respond quickly and strongly to supplementation.
of Iron deficiency
Impaired mental / intellectual function
Learning, growth and behavioural disturbances in children
Poor body temperature regulation
Some types of deafness
with other minerals and vitamins
Iron levels are affected by the presence of a wide variety
of other vitamins and minerals.
Most of these either increase or decrease iron absorption.
In addition, ferrous iron renders Vitamin
which reduce Iron absorption / increase excretion
Lignin (in fibrous vegetables)
Low stomach acid
Phosphates (e.g. in soft drinks)
Phytates (in cereals)
Polyphenols (red wine)
Tannins (tea, red wine)
Increase excretion / loss
Excessive exercising (through sweat)
Obvious blood loss (wounds, menstruation)
Anti-inflammatory use (due to gastric bleeding)
which increase Iron absorption / reduce excretion
Fructose (fruit sugar)
(milk and yoghurt)
Malic acid (fruits)
Sorbitol (fruits, some diabetic foods)
Tartaric acid (baking powder, tart fruits)
Normal amounts of Iron in the diet
|Children (0-10 years)
(inc adults) - males
(inc adults) - females
Sources of dietary Iron
|Breakfast cereals (fortified)
||Cooked kidney beans
|Raw Jerusalem artichokes
Haem iron supplements are better absorbed than their non-haem
counterparts (up to 35% versus 1-3%). Despite this, most
iron supplements, including those prescribed by Doctors are
usually of the non-haem form. In addition, non-haem forms
are much more associated with side-effects, such as diarrhoea,
flatulence and nausea. (What does this tell you about Doctors
knowledge of nutrition?)
Non-heam forms of iron iclude ferrous succinate, ferrous
fumarate and ferrous sulphate (sulfate). Because of its effect
on other minerals, iron is often best taken as a single supplement
(and at a separate time).
Children should not take single iron supplements unless
under medical supervision.
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