Iron is an essential nutrient for growth and development and plays a critical role in transferring oxygen around the body. It constitutes a vital part of haemoglobin, the oxygen-carrying component of red blood cells. Haemoglobin is responsible for transporting oxygen from the lungs to the body's tissues and carbon dioxide from the tissues to the lungs. The mineral also plays a part in energy production, muscle function, DNA synthesis and the immune system. We get most of the iron we need from food and our body carefully monitors its levels of iron; absorbing more when demand is high and less when stores are adequate. Iron is stored primarily in the bone marrow and liver.
The Recommended Daily Allowance (RDA) for iron is 8.7mg/day for men and postmenopausal women. For younger women it is 14.8mg per day, with an additional requirement recommended during pregnancy.
Iron deficiency is surprisingly common in the UK and is particularly prevalent among infants under two, teenage girls, pregnant women and the elderly. According to government surveys, the majority of women do not reach their dietary target of 14.8mg.
Iron deficiency
Iron deficiency may be due to one or a combination of the following factors:
- Blood loss. This is the most common cause of iron deficiency in women of childbearing age. This is most often due to excessive menstrual bleeding. Other causes of blood loss include bleeding from peptic ulcers, haemorrhoids and donating blood.
- Increased iron requirement. Periods of growth during childhood and adolescence sharply increases the need for iron. The increased need for iron during pregnancymay not be met through diet alone and so supplementation may be advised to pregnant women as necessary. If you're pregnant and are concerned you may be deficient in iron please consult your doctor.
- Inadequate dietary intake. This is also a common cause of deficiency. It is good to remember that plant-based sources of iron are a little harder for the body to absorb and that vitamin C will aid in absorption of all forms of iron. Typical infant diets, which are high in milk and cereals, can also be low in iron. Try a cereal fortified with iron to up intake.
- Diminished iron absorption. This is often due to reduced gastric acid secretion in the stomach; such as atrophic gastritis (common in the elderly), chronic diarrhoea or prolonged use of antacids.
Anaemia
Periods of rapid growth such as adolescence, heavy bleeding, busy lifestyles and lack of iron in your diet will result in your body drawing on its iron reserve. Initially there are no symptoms, but as your iron supply dwindles, so does your body's ability to produce healthy red blood cells. The result is low numbers of red blood cells circulating the blood, a condition called iron-deficiency
anaemia. Symptoms of anaemia include weakness, fatigue*, pale complexion, breathlessness, palpitations and an increased susceptibility to infection. Anaemic children have difficulty concentrating and may find it difficult to learn. Doctors can determine levels of body iron stores through a serum ferritin test.
*A note on haemochromatosis...
Haemochromatosis is a specific genetic disorder in which iron builds up over time, leading to excessive levels. If you have a family member with haemochromatosis, you should be screened to determine if you are at risk.
It is hard to diagnose – but one of the symptoms is fatigue. If you are feeling very tired all the time, it is recommended that you go to your GP and have a blood test before embarking on iron supplementation.
Supplements and safety
Anaemia requires a careful diagnosis and treatment to correct the underlying cause. Consult a doctor before taking an iron supplement. When prescribed by a doctor, iron is typically taken in a form called ferrous salts - ferrous sulphate, ferrous fumerate or ferrous gluconate. Side effects of iron supplements may include constipation and stomach upsets so be cautious and do not exceed the recommended amount. Keep all supplements containing iron out of reach of children.
Friends and foes
It must be pointed out that there are two forms of iron. Haem iron is found in animal products and is the most efficiently absorbed form of iron. Non-haem iron is found in plant foods and the body finds it more difficult to absorb by comparison. Vitamin C is a strong promoter of iron absorption, and when vitamin C rich foods are combined with foods rich in iron, absorption of the iron is substantially increased. Watch the amount of tea you consume as a substance called tannins found in tea is thought to inhibit the absorption of iron. Be aware that decaffeinated teas contain just as much tannin as normal tea. Foods high in phytates and oxylates, such as spinach, nuts, chocolate, parsley and rhubarb may also have a negative impact on iron absorption so just make sure you try to eat a varied, balanced diet.
Rich sources of iron
| Liver, beef & lamb | Soybeans |
| Clams, mussels & oysters | Lentils |
| Kidney beans | Tofu |
| Leafy green vegetables | Blackstrapp molasses |
| Dried figs & apricots | Quinoa |
| Oatmeal, rye | Chickpeas |
| Brewers yeast | Pinto beans |
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