Iron

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Iron

• In Health Disease

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Iron

• Iron is a trace element nutrient that the body
  uses for several discrete areas of normal health
  and function.
• The primary role of iron is in the formation of
  hemoglobin and myoglobin.
• The body also uses iron in many enzymes that are
  critical for metabolism. These enzymes, called
  cytochromes are required for the metabolism and
  detoxification of many natural compounds in the
  body as well as chemicals, drugs and
  environmental pollutants.
• DNA synthesis also requires an iron-containing
  enzyme, which is why iron is so important for
  growth, development and wound healing.

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Uses of Iron in the Body

• Iron has numerous uses in nature mainly due to
  simple aqueous chemistry that this transitional
  metal can undergo.
• Most important reaction is the reversible
  1-electron oxidation-reduction reaction that
  switches iron between its 2 common oxidation
  states ferrous ferric.
• This reaction is exploited by most iron-dependent
  enzymes involved in electron transport or oxygen
  carriage.

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Myoglobin

• Myoglobin and haemoglobin are proteins that serve
  all of the oxygen transport and storage needs of
  animals
• Myoglobin is the oxygen storage protein for
  tissues in almost all animals, and is the oxygen
  transport protein in some invertebrates
• Myoglobin is comprised of a single polypeptide
  chain of helical secondary structure, which is
  wrapped around a functionally essential
  prosthetic group called a heme.
• The heme molecule is a porphyrin ring complexed
  with Fe(II), and is responsible for the
  oxygen-binding properties of myoglobin
• The heme is bound non-covalently in a hydrophobic
  cleft of myoglobin.
• The myoglobin protein surrounds the heme
  prosthetic group like a cage, protecting the
  oxygen from release until the tissue needs it.

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Haemoglobin

• Most oxygen is transported bound to haemoglobin.
• HAEMOGLOBIN OXYGEN OXYHAEMOGLOBIN.
• Each haemoglobin molecule can transport 4 oxygen
  molecules.
• Haemoglobin, like myoglobin is an oxygen-binding
  protein.
• Whereas myoglobin exists as a single polypeptide
  chain, haemoglobin is a tetramer each of the
  four subunits is similar in terms of fold to
  myoglobin.
• Haemoglobin is a hetero-tetramer, consisting of
  two alpha subunits and two beta subunits (a
  "dimer of dimers"), the alpha subunits (141
  residues in human haemoglobin) and beta subunits
  (146) being homologous.
• The reaction where haemoglobin takes up oxygen
  occurs when the concentration of oxygen is high
  (e.g. in the lung capillaries) and the reverse
  reaction where the oxygen is released occurs when
  the concentration of oxygen is low (e.g. in the
  muscle capillaries).

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Intake of Iron

• Iron is found in two primary forms in food.
• Heme Iron
• Non-Heme Iron
• Heme Iron is regarded at the best source of iron.
  This is the form of iron found in animal sources
  such as lean red meat, dark poultry, shrimp and
  tuna.
• Non-Heme Iron is found in plants and are
  typically considered to be harder to absorb
  because it takes extra effort by the digestive
  system to free them from the foods they are in.

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Absorption of Iron

• Absorption of non-heme iron can be inhibited or
  enhanced by other substances that are ingested at
  the same time. Substances that inhibit the
  absorption of non-heme iron include tannins in
  tea oxalates in green vegetables, chocolate,
  berries and other foods and compounds in grains,
  soy protein and egg yolks. Coffee and tea when
  consumed with iron can reduce absorption by 40
  and 60 respectively.
• Absorption of plant-iron can be enhanced by
  simultaneous ingestion of heme iron. Other
  substances that naturally improve absorption
  include vitamin C organic acids such as citric
  acid, lactic acid, or malic acid and
  frucooligosaccharides (FOS).Iron in supplements

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Iron Requirements

• You should be able to get all the iron you need
  from your daily diet. This is
• 67-11 mg a day for men
• 11-15 mg a day for women
• There are several reasons why an individual will
  not absorb all the iron they need from their
  diet. Menstruation
• Pregnancy
• People who take aspirin daily
• Parasitic infections
• Disease
• Any condition that causes sustained blood loss
• Diet

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Iron Supplements

• There are a variety of iron forms sold as
  nutritional supplements. Iron supplements can be
  challenging to those who need to take them
  because the nutrient when isolated is not easy to
  digest and can readily lead to nausea,
  constipation or both.
• Most of the iron supplements on the market are
  iron salts. All contain different amounts of
  elemental iron, so it is important to read the
  labels carefully.
• You may also find iron supplements that are
  fortified with compounds such as vitamin C that
  enhance absorption.

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Iron Supplements
Generally, iron supplementation therapy is an
oral therapy, and parenteral iron therapy
(intravenously or intramuscular) is only given
when absorption is seriously compromised (by
illnesses, or when the patient cannot swallow)
Since iron stores in the body are generally
depleted, and there is a limit to what the body
can process (about 100mg per day) without iron
poisoning.
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Toxicity

• Usually the digestive system controls the amount
  of iron being absorb so that when the bodys iron
  stores are high very little iron is absorbed.
  However, some peoples genetic makeup means that
  they do not control the amount of iron they
  absorb very well (about 1 in 200 people).
• Extra iron may build up in organs such as the
  liver and heart and cause liver and heart
  disease. This condition is called
  haemochromatosis.
• Haemochromatosis can be treated by making regular
  blood donations to remove the extra iron.

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Toxicity

• The side effects of taking high doses of iron
  include constipation, nausea, vomiting and
  stomach pain.
• Very high doses of iron can be fatal,
  particularly if taken by children, so always keep
  any iron supplements out of the reach of
  children.
• Side effects of therapy with iron are most often
  diarrhoea or constipation and abdominal
  discomfort.

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Current Issues About Iron

• Some evidence suggests that iron can stimulate
  the activity of free radicals (the natural
  by-products of oxygen metabolism) that are
  associated with chronic diseases, including
  cardiovascular disease. Free radicals may inflame
  and damage coronary arteries, the blood vessels
  that supply the heart muscle and lead to
  atherosclerosis.
• Some researchers have raised concerns about
  interactions between iron, zinc, and calcium.
  When iron and zinc supplements are given together
  in a water solution and without food, greater
  doses of iron may decrease zinc absorption.

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