Iron
Iron is the building block of haemoglobin, which carries oxygen in the blood. Iron deficiency is one of the most common nutrient shortfalls in the world.
| Type | Mineral (trace element) |
|---|---|
| Main roles |
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| Sources |
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| Deficiency note | Iron deficiency is among the most widespread nutrient shortfalls in the world; a definite diagnosis is made with a blood test, and the symptoms can have other causes. |
| Caution | Iron supplements should not be used without testing; unnecessary iron can cause digestive complaints and is unsuitable in some inherited conditions. |
The carrier of oxygen
Iron sits at the centre of the haemoglobin in red blood cells and enables oxygen to be carried from the lungs to the tissues. It is also a component of myoglobin, which stores oxygen in muscle, and of some enzymes at work in producing energy. Requirements vary markedly with age, sex and circumstances; the need rises in menstruating women, in pregnancy and in growing children.
Two kinds of iron: haem and non-haem
The "haem iron" in meat, poultry and fish is absorbed efficiently by the body. The "non-haem iron" in plant sources such as lentils, white beans, spinach and grape molasses is absorbed at a lower rate and is affected by what else the meal contains. Practical tips: combining a plant iron source with vitamin C (lemon, tomato, peppers) increases absorption, and leaving a gap between the meal and a cup of tea or coffee, rather than drinking them together, softens the absorption-reducing effect of compounds in those drinks.
The right route on deficiency and supplements
A long-standing shortfall in intake, or losses, can progress to depleted iron stores and to anaemia, while symptoms such as tiredness and pallor can also stem from many other causes. Starting an iron supplement on your own on the strength of a symptom is therefore not the right thing to do: unnecessary iron can cause digestive complaints and is unsuitable in some inherited conditions (disorders of iron accumulation). A blood test and a doctor's assessment reveal both the deficiency and its cause.
Related terms: Vitamin B12, Vitamin C, Lentils, Spinach