Iron, Food Resource [http://food.oregonstate.edu/], Oregon State University, Corvallis, OR

FOOD QUALITY EFFECTS OF FORTIFICATION IRON

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REPRINTS, COPIES
Additive
Iron
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Iron Can Initiate Hydrolytic Rancidity of Foods
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Iron and Color in Foods
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Iron Fortification, Links, and References
______ Nitrite/Nitrate in Food
______ Fortification
______ Sulfite in Food
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The purpose of iron enrichment or fortification of foods is to prevent or reduce iron deficiency anemia in a target population. Iron deficiency anemia is common throughout much of the world. It is not limited to areas of low socioeconomic status, and is fairly common in the United States. It is more common in women and children than in men due to menstrual loss (women), low initial stores (children) and to lower dietary intake of iron-rich foods. (This is doubly true when women and children are strongly urged to consume more dairy products to prevent osteoporosis and "build strong bones" - most dairy foods are poor iron sources, and people tend to choose them in place of meat, fish, or poultry. )

Iron fortification of flour and other foods in the United States was instituted in 1943 (War Food Order No. 1) when it was observed that alarmingly many military recruits were suffering from iron deficiency anemia and other nutritional diseases. Permissible levels of iron enrichment of foods are specified in FDA regulations:


FOOD ITEM	shall contain: Iron (mg/lb)
Enriched flour	20
Enriched rice	16-32
Enriched corn grits	13-26
Enriched macaroni	13-16.5
Enriched bread, rolls, buns	12.5

The regulations further state that forms of iron used must be "harmless and assimilable".

Iron is present in food systems in three oxidation states: the elemental form (FE0), ferrous iron (Fe+2), and ferric iron (Fe+3). Different food systems dictate which form of iron will need to be used. The general properties of the different forms of iron are shown in the table below:

Type of iron solubility reactivity bioavailability

elemental low very low medium - depends largely on size of particles

ferrous high high highest

ferric medium medium lower than ferrous - similar to elemental

One general trend worth noting is that bioavailability is closely associated with reactivity; in other words, the more available the iron is, the more problems we will be likely to have with undesirable reactions in foods.

Elemental iron is commonly used in extruded foods such as breakfast cereals (packaging will list "reduced iron"). (In fact, a common elementary school science fair project is to bury a magnet in a bowlful of cereal and milk and attract the iron filings which slough off of the cereal. The wise child takes advantage of this knowledge by throwing it back at parents who tell her not to slurp the cereal milk.). Elemental iron is dark grey in color and has potential to discolor foods by showing up as dark flecks. The smaller the particles, the less they show up - however, smaller particles are more expensive to produce. Smaller particles are also more bioavailable than larger ones, so, in theory, less could be used to get the desired health benefits. Elemental or reduced iron is very stable under most circumstances.

Ferrous iron is the cheapest and most effective form of fortification iron; it is also the most reactive. Foods fortified with ferrous iron tend to be less shelf-stable and more liable to rancidity. Flour can be successfully fortified with ferrous iron if storage conditions are controlled and the storage time is not extreme.

Ferric iron is less reactive, less soluble, and less bioavailable than ferrous iron. It is also more expensive. It tends to work well in foods such as pastas and packaged foods which must have a long shelf life.

Updated: Wednesday, October 24, 2007.

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