Last modified: 21 November 2019
An essential element for the good functioning of cells, iron should be found in sufficiant quantities in our body. Some food can make the absorption of iron easier; others can stop it.
Iron is important for us
Iron is a part of hemoglobin. When it is bound to oxygen, it becomes oxidized.That’s the explanation on why hemoglobin in venous blood (non-oxidized iron) is dark purple and the one with arterial blood (oxidized iron) is a lighter red. The function of iron is to carry oxygen from the lungs to the cells. It’s important for the formation of red cells. It’s also a cofactor for enzymes and other proteins. Myoglobin, a molecule similar to hemoglobin, also contains iron. It is in the muscles and the function is to stock oxygen. You can’t be without it.
Facilitator or inhibitor
The alimentary iron is found in two forms : heme iron and non-heme iron. Food from animals such as meat, poultry, fish and seafood contain heme iron. It’s iron associated to myoglobin. In this form, it’s absorbed more easily. However, the quantity of myoglobin changes upon species. Thus, red meat (beef) is richer in iron than white meat (poultry, pork). Non-heme iron is also found in these foods.
Eggs and food from plants such as a few vegetables, dried fruits, beans and other cereal products (cereals with whole grain and pastas) contain non-heme iron not easily absorbed. All is not lost! Some food rich in vitamin C, such as oranges and green peppers, increase the solubility of iron and it becomes more easily absorbed. Food with heme iron also help this assimilation. So, eat some meat with vegetables to dispose of the problem. An absorption of iron can be increased by up to four times.
But, look out for inhibitors such as polyphenols contained in teas, coffees and cocoa! They form an insoluble complex with iron that reduced its absorption. Iron is eliminated through the intestines. There are also oxalates from spinach and phytates from whole grain that cause problems.
The body contains about 4-5 grams of iron. One part, about 2.5 grams, is associated to red cells. During their destruction, most of the iron (25-30 milligrams) is comes back and is reused. Instestines should absorb 1-2 milligrams per day to offset the losses. So, iron requirements is about 8 milligrams per day for a man and 18 milligrams per day for a woman. Diversified alimentation will allow avoiding deficiency in iron. However, if you have a deficiency because you have a celiac disease for example, you must reduce your intake of tea, coffee or cocoa. Wait one hour after a meal before taking them.