Iron and anaemia
Two billion people worldwide who don’t have enough iron in their blood suffer from anaemia. Double that number are iron deficient to some extent. In the developing world, anaemic people are more vulnerable to infection from diseases.
Existing iron supplements, however, are fraught with side-effects. Now, MRC scientists have developed a new type of iron supplement that is less harmful. It has the potential to boost the health of billions of people across the globe.
What is Anaemia?
Anaemia has been known since ancient times. It is caused by a deficiency of iron, which can result in a shortage of haemoglobin in the blood. Haemoglobin carries oxygen around the body, so a reduced amount results in less oxygen being circulated.
In Europe, 10-30 per cent of pre-menopausal women suffer from iron deficiency and 1.5-14 per cent from iron deficiency anaemia. An MRC study of 1,700 British people showed that 44 per cent of adolescent girls aged 11 to 19 years had low iron intakes1. Vegetarians are particularly at risk because meat is a good source of dietary iron.
Lack of iron can affect the brain, the workings of the body and its temperature control. It also reduces the effectiveness of the immune system, so in developing countries people become more susceptible to disease. Persistent iron deficiency during childhood may have long-term consequences in adulthood, such as abnormal behaviour.
Economic burden
Studies have shown that iron deficiency affects the productivity of workers. For example, anaemic tea pickers in Sri Lanka are more tired and weak than their non-anaemic colleagues3. Indonesian researchers analysed anaemic women and found that they carried out less housework and were less productive in non-physically strenuous factory work4.
According to the World Health Organization (WHO), iron deficiency has been one of the most expensive diseases in the world due to lost productivity. Scientists analysing the economic consequences of iron deficiency reckoned that iron deficiency in adults cost developing countries an average 0.6 per cent of their gross domestic product (GDP)2. When the damage to children’s intellectual development and control of movement due to iron deficiency is added, the figure rises to 4 per cent of GDP. The WHO believes that timely treatment can restore personal health and raise national productivity levels by as much as 20 per cent.
Irons in the fire
The WHO recommends that the diet of all pre-school children in developing countries should be supplemented with iron. As a result, oral iron preparations are widely used. However, the most common, simple ‘ferrous’ (Fe2+) salts, often cause side effects such as abdominal pain, constipation, diarrhoea and nausea. MRC scientists showed that ingestion of ferrous sulphate leads to increased production of a form of iron that causes acute damage to the inside of the intestine5.
The alternative to ferrous compounds are ferric (Fe3+) preparations in which iron is in a different chemical form. These cause fewer side effects. They are not as soluble and therefore are less well absorbed by the body. MRC scientists at the MRC Human Nutrition Research Unit in Cambridge have worked with iron in this state to create a new supplement – mixing it with components of food, for example, vitamins and proteins, to make it more soluble.
Supported by MRC Technology, the new supplement is being tried in volunteers up to the end of 2007, and already has promising results. The MRC product is cheap and simple to make.
There are other products using the same iron form, such as a Swiss iron-sugar capsule6. However, the iron in this product is extremely poorly absorbed, and the capsules are currently not available in the UK. Other, similar, iron complexes are expensive and have associated safety concerns.
Dilemma in the developing world
The problem with the use of iron supplements in the developing world is that they are associated with increased risk of hospitalisation, primarily due to malaria and infectious disease7. Scientists aren’t sure why – it may be because the malaria parasite or mosquito is attracted to the iron. Researchers advise that, in areas of high malaria infection rates, it is essential to screen initially for iron deficiency and provide iron only to those who are in need, monitoring them closely for infection.
Researchers also recommend being cautious when supplementing iron in children whose iron status is not known and who are apparently growing normally. A trial, carried out by a team in India, indicated that children who already had sufficient iron levels decreased their weight gain in response to iron therapy8.
References
1. Thane et al. (2003). Risk factors for low iron intake and poor iron status in a national sample of British young people aged 4-18 years. Public Health Nutr, 6, 485.
2. Horton & Ross (2003). The economics of iron deficiency. Food Policy, 28, 51.
3. Edgerton et al, (1979). Iron-deficiency anaemia and its effect on worker productivity and activity patterns. BMJ, 2, 1546.
4. Scholz et al. (1997). Anaemia is associated with reduced productivity of women workers even in less-physically-strenuous tasks. Br J Nutr. 77, 47.
5. Rooyakkers et al. (2002). Ferric saccharate induces oxygen radical stress and endothelial dysfunction in vivo. Eur J Clin Invest, 32, 9.
6. Kaltwasser et al. (1987). Bioavailability and therapeutic efficacy of bivalent and trivalent iron preparations. Arzneimittelforschung, 37, 122.
7. Sazawal et al. (2006). Effect of routine prophylactic supplementation with iron and folic acid on admission to hospital and mortality in preschool children in a high malaria transmission setting: community-based, randomized placebo-controlled trial. The Lancet, 367, 133.
8. Majumdar et al. (2003). The effect of iron therapy on the growth of iron-replete and iron-deplete children. Journal of Tropical Pediatrics, 49, 84.
MRC, July 2007