Iron supplements come in numerous chemical types and forms, each of which has its own drawbacks and benefits. You might take a certain type of iron supplement because of its rate of absorption, to avoid associated gastrointestinal side effects or for ease of ingestion. Don't take any form of iron supplement without first consulting your doctor, because iron supplementation can be dangerous for some people, especially children.
Chemical Types
The two main valences of iron supplements are ferrous iron and ferric iron. The most common form of ferric iron is ferric citrate, while the most common type of ferrous iron is ferrous sulfate. Ferrous lactate, gluconate, succinate, glutamate, glycine and ammonium citrate are other types of ferrous iron supplements. Other chemical forms include ferrous fumarate, iron glycine amino acid chelate and heme iron concentrate. Iron sucrose is a type of iron sold under the brand name Venofer, while iron dextran complex is also known as INFeD or Dexferrum, and polysaccharide-iron complex is sold as Ferrex 150, ProFe, Poly-Iron 150, Niferex or Nu-Iron 150. Other common brand names of iron supplements include Hemocyte, Fergon, Feosol, Femiron and Elite Iron.
Supplement Forms
In addition to basic tablets and capsules, iron supplements are available in many other forms, such as solutions, liquids, suspensions, elixirs and syrups. Some iron capsules are extended-release or liquid-filled, while tablets are sometimes chewable, enteric-coated or extended-release. Some types of iron supplements are injected into a vein; these include iron sucrose and iron dextran complex. Polysaccharide-iron complex supplements are available as capsules or liquids, while most common ferrous and ferric iron salts are available in most supplement forms.
Benefits
In general, your body absorbs ferrous iron supplements better than ferric iron, notes the University of Michigan Health System. Enteric-coated tablets can prevent some side effects like nausea, constipation and bloating while delaying absorption of the iron. Iron glycine amino acid chelate and heme iron concentrate supplements are easily absorbed and also tend to cause fewer side effects. Ferrous iron forms are more readily available as over-the-counter supplements than other types of iron, which may require a prescription from a doctor. Additionally, iron supplements that come in the form of solutions, liquids, syrups, suspensions or elixirs are appropriate for people who have trouble swallowing pills and for young children.
Drawbacks
Although ferrous sulfate is the most common type of iron supplement, it often causes gastrointestinal side effects like nausea, constipation and bloating, typically when the supplement isn't enteric-coated, says the University of Michigan Health System. Enteric-coated forms don't absorb as well as standard iron supplements, however. Although injected forms of iron are perhaps the best absorbed, you can get these types of iron only from your doctor in a hospital or similar healthcare facility. Most types of iron supplements -- except for enteric-coated types -- can cause stomach pain, nausea or vomiting, diarrhea, constipation and black stools, but injectable forms such as iron sucrose can also cause allergic reactions, dizziness and headaches.
References
- MayoClinic.com: Iron Supplement (Oral Route, Parenteral Route)
- University of Maryland Medical Center: Iron
- University of Michigan Health System: Iron
- University of Pittsburgh Medical Center: Iron Sucrose
- University of Pittsburgh Medical Center: Iron Dextran Complex
- University of Pittsburgh Medical Center: Polysaccharide-Iron Complex
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