Iron. The energy mineral.

Iron 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.

Although 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.

As you 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.

Two forms 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 products, especially kidney 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 production)
• Antioxidant
• May have anti-cancer properties
• Powerful immune-system booster

Iron deficiency

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 the diet.

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.

Symptoms of Iron deficiency

Anaemia
Tiredness
Pale skin
Sleep problems
"Restless legs"
Impaired mental / intellectual function
Learning, growth and behavioural disturbances in children
Breathlessness
Poor body temperature regulation
Frequent infections
Some types of deafness

Association 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 E inactive.

Factors which reduce Iron absorption / increase excretion

Reduce absorption
Antacid use
Cadmium
Calcium
Cobalt
Copper
Legume proteins
Lignin (in fibrous vegetables)
Low stomach acid
Manganese
Phosphates (e.g. in soft drinks)
Phytates (in cereals)
Polyphenols (red wine)
Tannins (tea, red wine)
Wheat bran

Increase excretion / loss
Excessive exercising (through sweat)
Obvious blood loss (wounds, menstruation)
Anti-inflammatory use (due to gastric bleeding)

Factors which increase Iron absorption / reduce excretion

Alcohol
Citric acid
Cysteine
Fructose (fruit sugar)
Histidine
Lactic acid (milk and yoghurt)
Lysine
Malic acid (fruits)
Pregnancy
Sorbitol (fruits, some diabetic foods)
Tartaric acid (baking powder, tart fruits)
Vitamin C

Normal amounts of Iron in the diet

Sources of dietary Iron

Iron supplements

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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