From the Guidelines
The primary sources of iron for the body are both animal and plant foods, with animal sources providing heme iron and plant sources providing non-heme iron. Heme iron, which is more easily absorbed by the body, is found in red meat (especially beef and liver), poultry, and seafood (particularly clams, oysters, and mussels) 1. Non-heme iron sources include beans, lentils, tofu, spinach, kale, fortified cereals, whole grains, and dried fruits like raisins and apricots. The body absorbs heme iron at a rate of about 15-35%, while non-heme iron absorption is lower at 2-20% 1.
- Key points to consider:
- Vitamin C can enhance non-heme iron absorption when consumed together, so pairing plant iron sources with citrus fruits, bell peppers, or tomatoes is beneficial 1.
- Conversely, calcium, tannins in tea and coffee, and phytates in some grains can inhibit iron absorption 1.
- For those with iron deficiency, supplements containing ferrous sulfate, ferrous gluconate, or ferrous fumarate may be recommended, typically at doses of 60-200 mg of elemental iron daily, but these should be taken under medical supervision to avoid iron overload 1.
- It is essential to note that the most recent and highest quality study, 1, provides the most up-to-date information on iron sources and absorption, and its findings should be prioritized in clinical practice.
From the FDA Drug Label
16 HOW SUPPLIED Ferrous Sulfate Tablets are available as follows: Each tablet contains 324mg of ferrous sulfate, equivalent to 65mg of elemental iron, providing 362% of the U.S. recommended daily intake (RDI) of iron for adults and children 4 and older.
The FDA drug label does not answer the question.
From the Research
Primary Sources of Iron for the Body
The primary sources of iron for the body are not explicitly stated in the provided studies. However, the studies discuss various forms of iron supplements and their efficacy in treating iron deficiency anemia.
Iron Supplements
- Ferrous sulfate is a commonly prescribed oral iron supplement 2
- Ferric pyrophosphate conveyed by a phospholipid and sucrester matrix (sucrosome) is another form of oral iron supplement 3
- Ferrous ascorbate and oral iron with vitamin C are also used to treat iron deficiency anemia 4
- Lipophilic iron donor ferric maltol and nanoparticle encapsulated sucrosomial iron are novel iron formulations 2
Iron Absorption
- Iron absorption from supplements is greater with alternate day than with consecutive day dosing in iron-deficient anemic women 5
- Vitamin C enhances iron absorption and may also prevent liver damage induced by iron overload 6
Treatment of Iron Deficiency Anemia
- Oral iron supplementation is usually efficacious in correcting iron-deficiency anemia and replenishing iron stores 2
- Intravenous iron therapy can rapidly achieve therapeutic targets without gastrointestinal complications when oral iron supplementation is contraindicated 2
- Sucrosomial iron is a valid first option for the treatment of iron deficiency and iron deficiency anemia, especially for subjects who are intolerant or refractory to conventional iron salts 3