If you have been diagnosed with iron deficiency or iron deficiency anemia, chances are you been advised to use oral iron supplements, along with eating more foods rich in iron. Though there are several available at your pharmacy, resist the urge to just pick up any supplement because iron deficiency is not something you should try to treat on your own. Working with your doctor or pharmacist will allow you to get the right type and dose, and hopefully limit the undesired effects you may experience.
Not all iron supplements – or people for that matter – are the same; the one you should take depends on your specific needs. All iron supplements are effective (in terms of ability to increase hemoglobin and hematocrit) in a normal, healthy gut; however, the amount of elemental iron available for absorption by the body, the possibility of developing adverse effects, and more convenient dosing, are all important factors to consider when choosing an iron supplement.
It’s important to look at how much elemental iron (amount of iron that is available to be absorbed) is in each tablet/capsule. While absorption can be affected by various elements, in a normal healthy gut heme iron has a higher absorption rate than non-heme iron (25% versus 16.8% respectively). At the end of the day, the more iron that is readily available, the more that can be absorbed.
Oral Iron Preparations (Tablets/Capsules)*: Amount of Elemental Iron, Ranked Highest to Lowest
|Oral Iron||Strength per Capsule/Tablet||Elemental Iron per Capsule/Tablet||Heme Iron/Non-Heme Iron||Ionic/Non-Ionic|
|Polysaccharide-Iron Complex (eg. FeraMAX® 150)||150 mg||150 mg||Non-heme||Non-Ionic|
|Ferrous fumarate (eg. Palafer® & generics available)||300 mg||100 mg||Non-heme||Ionic|
|Ferrous sulphate (generics available)||300 mg||60 mg||Non-heme||Ionic|
|Ferrous sulphate dried sustained-release (eg. Slow-Fe®)||160 mg||50 mg||Non-heme||Ionic|
|Ferrous gluconate (generics available)||300 mg||35 mg||Non-heme||Ionic|
|Heme-Iron Polypeptide (eg. Proferrin®)||11 mg||11 mg||Heme||N/A|
*Anemia Guidelines for Family Medicine, 3rd Edition, 2014 (page 8)
The non-heme iron supplements listed above are either in ferrous (Fe2+, ionic) or ferric (Fe3+, non-ionic) forms. Iron salts, which are ionic, include ferrous fumarate (Palafer®) and ferrous sulfate (Slow Fe®). The only non-ionic option available in this market is a formulation called Polysaccharide-Iron Complex or PIC (FeraMAX®). To my knowledge, heme iron is not considered ionic nor non-ionic; Proferrin® is derived from bovine red blood cells.
Once prescribed, iron supplements are going to be used for a relatively long period of time, patients’ poor compliance is the primary reason for failure of therapy. Gastrointestinal (GI) side effects – stomach upset, abdominal distress, dark stool, and either constipation or diarrhea – are often the most common cause for temporary or permanent discontinuation. PIC and heme iron have both been noted to be easier on the digestive system and cause fewer GI side effects.
The British Columbia Ministry of Health Sciences outlines the incidence of side effects for the various oral iron preparations in their Guidelines and Protocols for Iron Deficiency:
Oral Iron Preparations (Tablets/Capsules): Incidence of Side Effects*, Ranked Least Incidence to Greatest Incidence
|Oral Iron||Incidence of Side Effects|
|Ferrous sulphate sustained-release||+|
*British Columbia Ministry of Health Services – Guidelines and Protocols: Iron Deficiency – Investigation and Management, 2010 http://www.bcguidelines.ca/pdf/iron_deficiency.pdf
Heme iron is also considered to be well tolerated. I will remind my vegetarian and vegan friends; however, that heme iron polypeptide is derived from animal proteins (bovine source).
As mentioned above, some supplements may offer more convenient dosing, which can be important depending on your lifestyle. Your doctor or pharmacist will assist you in determining the dosing regimen that best suits your needs, and hopefully reduces possible side effects as well.
Oral Iron Preparations (Tablets/Capsules): Adult Dose*, Ranked Most Convenient to Least Convenient
|Oral Iron||Adult Dosing|
|Polysaccharide-iron complex (150 mg of elemental iron)||1 capsule once a day|
|Ferrous fumarate (100 mg of elemental iron)||1 tablet 2-3 times a day|
|Heme iron polypeptide (11 mg of elemental iron)||1 capsule 2-3 times a day|
|Ferrous sulphate (60 mg of elemental iron)||1 tablet 2-3 times a day|
|Ferrous gluconate (35 mg of elemental iron)||1-3 tablets 2-3 times a day|
*Anemia Guidelines for Family Medicine, 3rd Edition, 2014 (page 11)
Choosing the right iron supplement depends on each patient’s individual needs. I always recommend speaking with your doctor or pharmacist for proper diagnosis and to assist in ensuring you get the right iron supplement for you.
This article was last updated on 11.14.2014
Content and advice provided on The Iron Maiden is for information purposes only and should not serve as a substitute for a licensed health care provider, who is knowledgeable about an individual’s unique health care needs