Trace Mineral- Iron Flashcards
Where is Iron found?
-Average human contains 4g
-2/3 occurs as haemoglobin (red blood cells)
What are the functions of Iron
-Vital for HAEMOGLOBIN PRODUCTION
-Needed to produce MYOGLOBIN- helps CATCH OXYGEN for use by muscles
-Important in metabolic processes, eg research shows Iron is needed for SYNTHESIS OF DNA (basic building block of all body cells)
What is Haemoglobin
-red pigment that gives blood cells their colour
-Transports OXYGEN from LUNGS to body’s TISSUES for ENERGY PRODUCTION
Where is Iron found, apart from Haemoglobin
-Iron is found in Myoglobin- a protein which acts as an OXYGEN CARRIER (needed for energy- prevents a build up of lactic acid) in muscles, also found in small amounts of body BODY CELLS- involved in ENZYME ACTIVITY
-Remaining Iron stored in body as FERRITIN (important storage form) and HAEMOSIDERIN, in liver spleen and bone marrow
-Stored Iron- important during the first six months of a baby’s life- only a small amount present in milk
How is Iron lost from the body
-Urine
-Sweat
-Shed in epithelial cells from skin and gut
-Blood- menstruation, accident
What are dietary sources of Iron
-Cereal products and bread- approx 34%
-Veg- approx 17%
-Meat- approx 17%
-Eggs- approx 2.8%
-White bread- fortified
-Dried fruit, pulses and wholegrain cereals (phytic acid present)
What are the two forms of Iron
Organic Iron
-ferrous Iron- HAEM IRON
-derived from foods containing haemoglobin
-absorbed relatively easily be body
eg red meat and offal (liver)
around 20-25% absorbed
Inorganic O=Iron
-Ferric Iron
-NON HAEM IRON
-derived from plant foods and egg yolk
-Insoluble form
-very poorly absorbed
as little as 2-5% absorbed
eg dark green leafy veg, chocolate, fortified breakfast cereals, bread
What factors promote absorption
ASCORBIC ACID aids iron absorption by:
-aiding reduction of FERRIC ACID TO FERROUS ACID- vitamin C is a reducing agent
-absorbed more readily in the haem/ ferrous form
Factors Inhibiting Absorption
-LOW STOMACH ACIDITY- gastric hydrochloric acid converts ferric acid (non haem) to ferrous (haem)
-if low gastric hydrochloric acid, the ferric iron won’t be as readily converted to ferrous- which is MORE EASILY ABSORBED into BLOODSTREAM
-PHYTIC ACID- found in wholegrains and phosphate found in egg yolk- these form an insoluble complex with iron, eg iron phytate
-OXALIC ACID- spinach and rhubarb- forms as insoluble complex with iron- iron oxalate
-TANNINS- (tannic acid)- found in tea- forms an insoluble complex- iron tannate
When can the body increase its absorption rates
-Only 10% of iron is absorbed
body can increase stores when:
-stores are depleted
-needs are high, eg during pregnancy
Deficiency of Iron
IRON DEFICIENCY ANAEMIA- most common nutritional disorder in the world
Cause of Iron Deficiency Anaemia
-If the amount of iron is insufficient, the deficiency is made up of the body’s iron stores
-If there is prolonged shortage and body’s iron stores are depleted, the haemoglobin levels of the blood fall- resulting in IRON DEFICIENCY ANAEMA
What are symptoms of Iron Deficiency Anaema
No oxygen/ reduced oxygen supply in blood
-Fatigue
-Weakness
-Pale Complexion
What groups may be vulnerable
-Babies- diet consists of milk- milk is low in iron- babies born with a store from mother- approx 6 months- provided the mother’s diet was adequate during pregnancy
-Pregnant Women- the foetus will be provided with iron first- mother’s needs must be met- PREVENT ANAEMIA during pregnancy
Girls and Women- greater need- due to monthly loss of blood during menstruation
Post injury/ operation- may result in considerable blood loss- iron needs to increase
-Vegetarian- diet consists of inorganic/ non-haem- not easily utilised in body- therefore greater likelihood of deficiency
-Elderly- blood cells are destroyed quickly- must be recreated- may have a poorly diet balanced diet- due to lack of motivation, increased lineliness and inadequate finance
What is an excess of Iron
-SIDEROSIS- rare
-HAEMOCHROMATOSIS- iron absorption poorly controlled by body
