Iron is a mineral that plays a vital rolein the body. Find out about its functions, the nutritional needs of the population and foods containing iron.
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Updated on 04/08/2016
Definition, functions and roles
Iron is a mineral that plays a vital rolein the body. It is necessary for the production of haemoglobin (a protein found in red blood cells that enables oxygen to be carried around the body), myoglobin (a muscle protein that stores oxygen), and enzymes involved in respiration and DNA synthesis. Most iron in the body (70%) isin the form of "haem iron" (associated with haemoglobin), with the rest being "non-haem iron" (used for transport and reserves).
Composition of foods containing iron
Meat products are good sources of iron, especially blood sausage (black pudding), liver and kidneys. There are also large quantities of iron in seafood (fish and shellfish), chocolate, wheatgerm, delicatessen meats, eggs and some fortified foods such as breakfast cereals. More important than the amount of iron in food is its quality, which matters because the body absorbs iron of plant origin differently to that from animal products. Thus, the assimilation of iron contained in meat products is 2.5 times higher than that of iron from plant products and dairy produce. Moreover, the simultaneous consumption of meat with vegetables or fruit rich in vitamin C (citrus fruits, kiwi, red fruit, cabbage, etc.) further improves the absorption of iron from plant sources.
Population Reference Intakes (PRI)
The PRI in iron were set to ensure appropriate reserves. They were estimatedat 9 mg/d for men and 16 mg/day for premenopausal women. They vary from 7 to 14 mg/day for children aged from 3 to 17 years.
Levels and sources of intake
In the INCA2 study, mean intakes of iron were 14.7 mg/day for adult men, 11.6 mg/day for adult women and about 10 mg/day in children.
Meat products (red and white meat, offal and delicatessen meats) are the main dietary source of iron. They account for 20% and 16% of iron ingested by adults and children respectively. In adults, the other foods contributing to iron intake are bread (10%) and vegetables (9%). In children, breakfast cereals also contribute 11% of the iron consumed.
Contrary to popular belief, pulses, despite their mean levels of iron, are secondary sources of supply: they provide less than 2% of iron ingested.
Risks of deficiency and excess intake
While iron deficiency at a very advanced stage leads to anaemia (hypoferric or iron deficiency anaemia), the consequences of a moderate deficiency are still unclear.A reduction in physical capacity and mental performance, reduced resistance to infections, disturbances during pregnancy and anomalies in maintaining body temperature are increasingly mentioned.
Epidemiological data report an association between high intakes of iron and an increase in the incidence of cardiovascular disease, type II diabetes and digestive cancers.However, inEurope, the risk of deleterious effects from high intakes (including fortified foods but excluding food supplements) is low, except for homozygous individuals with regard to haemochromatosis (SCF, 2006).