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Iron levels in Health

Low levels of Fe in the body can cause fatigue and anaemia.

The reason you can bleed to death is that loss of blood means loss of haemoglobin in your blood. This prevents cells from getting oxygen to produce energy and so they starve to death in your body.

The flip side to this is that too much iron in the body can cause Fe to form iron solids in body tissues, which is not healthy either. Too much iron has been implicated in causing cardiovascular disease.

It is important to have a balanced level of Fe in your body.

Food is the usual source of iron in the body, although dietary supplements are available. These foods are high in iron:

  • Red meat
  • Liver
  • Dark leafy greens
  • Dried fruit
  •  Egg yolks

Eating foods high in Vitamin C at the same time as eating iron-rich foods will help iron be absorbed into the body. (Most fruits are high in Vitamin C, particularly oranges, kiwifruit, and also red peppers).

 

Iron Reactions

However, Fe can be very dangerous in the body if it is released from haemoglobin. As already discussed in the post regarding malaria, free iron will react with hydrogen peroxide to create free radicals that attack DNA, killing cells and making you sick.

Fenton Reaction produces dangerous radical molecules in the body

The only place haeme (an iron centre with the immediate surrounding protein) from haemoglobin can be safely disposed of is in the liver, where a chemical pathway is available to recycle red blood cells. Haemoglobin is broken down into Bilirubin.

Bilirubin can then be broken down by certain wavelengths of light as well as enzymes in the body.

Neonatal hyperbilirubinaemia is a condition where newborn babies turn yellow because they cannot break down this yellow bilirubin.

This condition can be fixed by putting the baby under special blue lights. This light causes the bilirubin to break down. 

 Phototherapy used to treat a baby with jaundice.
 Photo: Wikipedia Commons, Rjmunro 
An interesting website to explore for more information is:

http://www.chemistry.wustl.edu/~edudev/LabTutorials/Ferritin/Ferritin.html

 

The Iron War

Iron is used for more than just oxygen transport in the body. Bacteria, yeast and fungi also need iron to live.

Interestingly, the first layer of protection against bacterial infection is at the entry points to the body: mouth, nose etc. Lactoferrin is an antibiotic produced in saliva and snot, which strips Fe from bacteria.

The idea is that if bacteria need Fe to reproduce and infect you, take their Fe off them and they will die.

However, bacteria have chemicals of their own. Siderophores, another chemical that binds strongly to iron helps bacteria to capture iron from their environments.

Siderophores are used to remove iron from transferrin iron transfer and storage proteins in the body. The siderophore is then absorbed by bacteria that breaks down the siderophore and stashes a source of iron for themselves.

Electron Micrograph of a colony of E. Coli bacteria.
Photo: Eric Erbe, US Department of Agriculture

Enterobactin (excreted by E. coli) is an extremely efficient siderophore. It is so strong, it can remove iron from glass.

Once the first-line defences have failed, the body’s next response to a bacterial invasion is the production of a molecule called siderocalin. Siderocalin binds enterobactin and so prevents bacteria getting any iron, killing them. 

However, bacteria are developing resistance to siderocalin and so the battle for iron- and life- continues.

To find out further information, have a look at the Public Library of Science article ‘The Battle for Iron between Bacterial pathogens and their Vertebrate Hosts’, available at:

http://www.plospathogens.org/article/info%3Adoi%2F10.1371%2Fjournal.ppat.1000949

This article about the bacterial gene that allows bacteria to steal iron from humans is also an interesting read:

http://www.sciencedaily.com/releases/2008/07/080731140223.htm

Iron is an essential mineral for humans and other life forms to function properly. It has an essential role in transporting oxygen around the human body and also in battling infection.

Like all minerals, it is important to have a safe level of it in the blood to prevent either anaemia (low iron) or cardiovascular disease (high iron).

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