Too much versus too little IRON (Fe)

Iron is stored in the liver, the spleen and the bone marrow and contributes to normal formation of red blood cells and haemoglobin and to normal oxygen transport in the body. It contributes to normal energy-yielding metabolism, to normal cognitive function, to the normal function of the immune system and to the reduction of tiredness and fatigue, and has a role in the process of cell division.

Malnutrition, phosphoproteins, a vitamin B12 deficiency or phytic acid salts in wholegrain products reduce the rate at which iron is absorbed. The absorption process is also disturbed by drinking larger amounts of coffee or tea. Good iron absorption is ensured by vitamins A, C, E and B12, hydrochloric acid and Ca, Cu and Mn. When taking anti-inflammatory medicines or in cases of bleeding, an increased intake of Fe is recommended. Women lose a lot of iron during menstruation, and during childbirth the losses are very high. In children and women, an insufficient intake of iron has been found in 90 % of cases.

A lack of iron leads to the appearance of anaemia, impairs the immune system and increases the risk of catching infectious diseases. The clinical symptoms are depression, pallor, reduced physical resistance, asthenia, reduced mental performance, palpitations and disturbances of the menstrual cycle.

Iron overload is rarer and occurs more often in men. The clinical symptoms include liver damage, copper-coloured skin or severe diabetes.

Food sources of iron are: red meat and meat products, liver, kidney, beef heart, spleen, fish and seafood, egg yolk, green vegetables, nuts, raisins, hazelnuts, apricots, cereals, beans, asparagus, beetroot, oats, nettles and sprouted soya beans. Iron from animal products is absorbed at 40 %, from vegetables at only 10 %.

Studies have found that the bioavailability of iron is increased by heat treatment that is not very long (blanching, sautéing, medium cooking; example: in tomatoes from 25 % to 34 %, peppers from 17 to 32 %). Cooking food for too long or chopping it before cooking leads to a loss of iron.

Water is low in iron, with the exception of natural iron-rich mineral waters, which are recommended in cases of anaemia.