Functions:
Iron is required for the production of red blood cells (a process known as haematopoiesis), but it's also part of haemoglobin (that is the pigment of the red blood cells) binding to the oxygen and thus facilitating its transport from the lungs via the arteries to all cells throughout the body.
Once the oxygen is delivered the iron (as part of haemoglobin) binds the carbon dioxide which is then transported back to the lung from where it gets exhaled.
Iron is also involved in the conversion of blood sugar to energy. Metabolic energy is crucial for athletes since it allows muscles to work at their optimum during exercise or when competing.
The production of enzymes (which play a vital role in the production of new cells, amino acids, hormones and neurotransmitters) also depends on iron, this aspect becomes crucial during the recovery process from illnesses or following strenuous exercise or competing.
The immune system is dependent on iron for its efficient functioning and physical and mental growth require sufficient iron levels, particularly important in childhood and pregnancy, where the developing baby solely depends on its mother's iron supplies.
Iron is lost by the body through a variety of ways including urination, defecation, sweating, and exfoliating of old skin cells. Bleeding contributes to further loss of iron which is why women have a higher demand for iron than men.
What food Iron is found in:
Good sources of iron include:
liver, meat, beans, nuts, dried fruit, such as dried apricots, wholegrains, such as brown rice, fortified breakfast cereals, soybean flour, most dark-green leafy vegetables, such as watercress and curly kale.
Although liver is a good source of iron, do not eat it if you are pregnant. This is because it is also rich in vitamin A, which can damage your unborn baby in large amounts.
There are two forms of iron in the diet: heme and nonheme. In foods from animal sources, such as meat, poultry and fish, about half the iron is heme iron and the rest is nonheme. Iron from dairy foods, eggs and plant-based foods is entirely nonheme. Iron is better absorbed by the body from heme sources. Vitamin C also improves absorption of both forms of iron when consumed at the same meal.
What symptoms and disorders Iron deficiency may cause:
If iron stores are low, normal haemoglobin production slows down, which means the transport of oxygen is diminished, resulting in symptoms such as fatigue, dizziness, and lowered immunity.
Inadequate dietary iron results in iron deficiency anemia, the most common nutritional deficiency in the world. Symptoms include reduced cognitive function, increased risk of infection and delayed development in infants.
Iron intake requirements are 1.8 times higher for vegetarians because nonheme iron is not absorbed as well as heme iron.
Problems related do excessive doses:
It’s not likely that you’ll get too much iron from dietary sources. However, high doses from supplements could cause harmful effects, ranging from gastrointestinal effects, such as nausea, vomiting and diarrhea, to cardiovascular, nervous system, kidney and liver effects. Children should never be given iron supplements unless under the guidance of a physician or qualified health professional. Iron toxicity (from high doses of supplements) in children can rapidly result in severe long-term effects or death.
People with the following conditions may be at risk of harmful effects due to high iron intakes and therefore should not consume excess amounts of iron: hereditary hemochromatosis (a condition that causes the body to absorb and store too much iron), chronic alcoholism, liver disease, iron-loading abnormalities and certain genetic disorders. Additionally, it is recommended that adult men and postmenopausal women avoid iron supplements and highly fortified foods because of their greater risk for iron overload, a condition that leads to iron accumulation in the body.
The side effects of taking high doses (over 20mg) of iron include constipation, nausea, vomiting, stomach pain.
Recommended doses for people in the UK:
Women who lose a lot of blood during their monthly period (heavy periods) may need to take iron supplements. Speak to your GP or a state-registered dietitian for more advice.