From the Guidelines
Heme iron, found in animal products like red meat, poultry, and fish, is the most easily absorbed form of iron, with an absorption rate of 15-35%. Non-heme iron from plant sources like spinach, beans, and fortified cereals is less bioavailable, with only 2-20% absorption 1. To maximize iron absorption, consume vitamin C-rich foods (citrus fruits, bell peppers, strawberries) alongside iron sources, as vitamin C enhances non-heme iron absorption by converting it to a more absorbable form 1.
Some key points to consider when trying to increase iron absorption include:
- Avoid consuming calcium, tannins (in tea and coffee), and phytates (in whole grains) with iron-rich meals, as these inhibit absorption 1.
- For those requiring supplementation, ferrous sulfate, ferrous gluconate, or ferrous fumarate are effective options, with ferrous sulfate typically providing 65mg of elemental iron per 325mg tablet 1.
- Taking iron supplements on an empty stomach with vitamin C improves absorption, though this may cause gastrointestinal discomfort for some people 1.
- Certain dietary manipulations may improve iron absorption, such as taking iron with 80 mg ascorbic acid on an empty stomach, which has been shown to improve iron absorption in a recent iron isotope study 1.
It's also important to note that the timing of iron intake can affect absorption, with some studies suggesting that taking iron every other day may improve tolerance, although more research is needed to confirm this 1. Overall, maximizing iron absorption is crucial for preventing iron deficiency anemia, and can be achieved through a combination of dietary changes and supplementation.
From the FDA Drug Label
Following intravenous administration, Venofer is dissociated into iron and sucrose and the iron is transported as a complex with transferrin to target cells including erythroid precursor cells. The iron in the precursor cells is incorporated into hemoglobin as the cells mature into red blood cells.
The iron from Venofer (iron sucrose) is easily absorbed, as it is transported to target cells and incorporated into hemoglobin.
- Key points:
- Iron is dissociated from sucrose after administration
- Iron is transported with transferrin to target cells
- Iron is incorporated into hemoglobin in erythroid precursor cells 2
From the Research
Types of Iron Supplements
- Ferrous sulfate is the simplest, least expensive, and most commonly prescribed oral iron supplement 3
- Other ferrous salts and ferric complexes with polysaccharides or succinylated milk proteins are also widely used 3
- Novel iron formulations have been developed, such as the lipophilic iron donor ferric maltol, or nanoparticle encapsulated sucrosomial® iron 3
- Ferric iron polymaltose complex preparations are also used as an alternative to ferrous sulphate preparations 4
Absorption and Efficacy
- Ferrous sulphate preparations have good bioavailability, efficacy, and acceptable tolerability 4
- Intravenous iron preparations can facilitate rapid iron repletion in one or two doses, both for absolute iron deficiency and functional iron deficiency 5
- Intravenous iron may work where oral iron has not, especially in cases of chronic inflammatory conditions, perioperative settings, and disorders associated with chronic blood loss 5
- Iron-fortified foods can be an effective method for preventing iron deficiency, especially in populations with high prevalence of iron deficiency 6
Comparison of Oral and Intravenous Iron
- Intravenous iron likely slightly increases Hb level and reduces anaemia in pregnancy compared to oral iron 7
- Intravenous iron may result in little to no difference in postpartum haemorrhage and blood transfusion rates compared to oral iron 7
- Intravenous iron likely does not increase adverse events, but the evidence is not conclusive 7