Iron deficiency - anaemia

Iron is an essential mineral that has several important roles in the body, including oxygen transport.  Anaemia is a condition in which the amount of haemoglobin or number of red blood cells (and consequently their oxygen-carrying capacity) is insufficient to meet the body’s physiological needs. There are several different types of anaemia, each with slightly different characteristics and causes. Iron deficiency is the most common cause of anaemia, it is  defined as a decrease in the total iron content of the body and can lead to anaemia when Iron levels are no longer sufficient for effective red blood cell production.

Iron deficiency is the most frequently encountered nutritional deficiency in the world, with some 2 billion people estimated to be suffering from it worldwide.  Although the disease prevalence is highest in developing countries, iron deficiency anaemia remains a significant problem in the developed world and has a prevalence of 2–5% among adult men and postmenopausal women. Furthermore During childbearing years, there is a higher incidence of iron deficiency anaemia in women due to iron loss through menstruation and pregnancy.

Iron deficiency anaemia can have very few signs, however the most common symptoms include, general tiredness and lethargy, dyspnoea (shortness of breath), and palpitations. Iron deficiency anaemia can result in, a decrease in work capacity, cardiopulmonary complications, decrease in immune status as well as potential complications to pregnancy.

As the name suggest iron deficiency anaemia occurs when there is not enough iron in the body, there are many reasons which can contribute to a state of iron deficiency, these include:
Blood loss from the gastrointestinal tract, which can be caused by Non-steroidal anti inflammatory drug use, peptic ulcers or carcinomas.

Menstruation blood loss
Increased demands of pregnancy

The modern western diet is rarely inadequate for iron unless there is a factor, such as those listed above, which results in an increased requirement. Iron is present in food in two forms, Haem and non-Haem. Haem iron is derived mainly form meat sources where as non-haem sources of iron come from Iron salts such as those found in plant foods.  Haem iron is better absorbed from the gut at a rate of around 15-20% compared to 5% for non-haem iron sources. Although some studies suggest vegetarians or vegans are more at risk of iron-deficiency anaemia due to the lack of meat in their diet, It is possible to attain enough iron via non meat foods.

Good sources of iron

• liver
• meat
• dried fruit, such as dried apricots, prunes, raisins
• wholegrains, such as brown rice
• fortified breakfast cereals
• soybean flour
• dark-green leafy vegetables
• beans

The degree to which iron is absorbed (or bioavailability) from the gut is also affected by interactions with other nutrients in food. Nutrients which influence the absorption of iron can be broadly grouped into two groups, promoters and inhibitors.

The most important promoters, which help increase the absorption of iron, include Vitamin C (ascorbic acid), citric acid, and vitamin A as well as the presences of meat.

Important inhibitors; which act to decrease the bioavailability of non-haem iron, are often one of a group of naturally occurring chemicals called Polyphenols. The best known example of a polyphenol inhibitor is Tannin, found in tea and coffee.  Calcium and phytate, a compound found mainly in the husks of grains, are also both major inhibitors of non-haem iron absorption.

What can be done?

If you are concerned about your Iron status or you experience symptoms of iron deficiency anaemia. The National Institute for Health and Care Excellence (NICE) recommend you contact your GP who may perform a verbal and physical examination or request a blood test to confirm the diagnosis.

Treatment usually involves taking iron supplements to replace missing iron and making necessary changes to address the underlying cause. If inadequate intake is suspected advice may also be given on how to include more iron in your diet.

Steve Fennell HCPC Registered Dietician

Page last reviewed on 23/05/2014