Iron in biology

Iron is an essential element for all forms of life and is non-toxic. The average human contains about 4 grams of iron. A lot of this is in hemoglobin, in the blood. Hemoglobin carries oxygen from our lungs to the cells, where it is needed for tissue respiration. People need iron in their diets to make hemoglobin and myoglobin, proteins that carry oxygen in the body. The iron is part of the protein molecule.

Function

Iron is needed for many enzymes to function normally. A lot of the iron in the body is in hemoglobin. Muscles use myoglobin to store oxygen for use inside the cells. Some enzymes in all cells need iron to help with energy production.

Iron in the body

Iron is also stored in the body in the liver, spleen, and bone marrow. When the body needs iron because it is not getting enough iron in the diet, the stored iron is used. More iron is needed during growth, menstruation, pregnancy, or when there is blood loss.

Iron in the diet

Iron is found in food in two forms, heme and non-heme iron. Heme iron, which makes up 40 percent of the iron in meat, poultry, and fish, is well absorbed. Non-heme iron, 60 percent of the iron in animal tissue and all the iron in plants (fruits, vegetables, grains, nuts) is less well absorbed. Because vegan diets only contain non-heme iron, vegans should be aware of foods that are high in iron and techniques that can promote iron absorption. Recommendations for iron for vegetarians (including vegans) may be as much as 1.8 times higher than for non-vegetarians. Some might expect that since the vegan diet contains a form of iron that is not that well absorbed, vegans might be prone to developing iron deficiency anemia. However, surveys of vegans have found that iron deficiency anemia is no more common among vegetarians than among the general population, although vegans tend to have lower iron stores.

See also

• Hemoglobin
• Myoglobin
• Enzymes
• Liver
• Spleen
• Bone marrow
• Diet
• Heme
• Non-heme iron
• Vegan diets
• Iron deficiency anemia

• 
  Drops of blood
• 
  Hemoglobin
• 
  Iron in biology
• 
  Heme b
• 
  Carboxyhemoglobin
• 
  Iron in biology
• 
  Red blood cells