Ferrous salts are commonly used for iron supplementation. But also ferric salts and iron amino acid chelates are available. They have different adverse effects and impact on food, if they are used for fortification (Nagpal & Choudhury, 2004, Camaschella, 2019).
If iron supplementation is required, several raw materials are available that can efficiently replenish iron stores, but may also cause adverse effects in the gastrointestinal tract. The most commonly used iron sources are ferrous sulphate, ferrous gluconate and ferrous fumarate (Anderson & Frazer, 2017), which are compared in table 575-0.4-01, whereas table 575-0.4-02 displays the recommended daily iron intake.
The most commonly used iron source are ferrous salts, as they are present in their reduced, ferric form (Fe2+) and can be absorbed directly by the human body (→). These include ferrous sulphate, fumarate, gluconate, succinate and lactate. They all offer rather inexpensive management for iron deficiency or anaemia (→), but differ in their bioavailibilty (Nagpal & Choudhury, 2004, Camaschella, 2019).
Ferrous sulphate, which is one of the standard management options, contains 20% elemental iron. It is mostly used in form of tablets as it easily oxidates in humid environments and therefore is not suitable for liquid application. Most ferrous salts have a uniformly good bioavailability, but are strongly influenced by dietary inhibitors. Therefore, their use as food fortificants is limited. Adverse effects such as gastrointestinal problems, discoloration of teeth by liquid products and toxicity through over dosage are also common (Nagpal & Choudhury, 2004, Camaschella, 2019).
Ferric salts are rarely used as food supplements as they have to be reduced to Fe2+ by the body prior to absorption (→). Their bioavailability is usually lower than that of ferrous sulphate, but simultaneously the risk of toxification is reduced (Nagpal & Choudhury, 2004).
Another iron source are iron amino acid chelates, of which ferrous bisglycinate (→) is the most commonly used. It contains 20% elemental iron and, like most of the iron amino acid chelates, has little impact on the taste or appearance of food if it is used for fortification. Ferrous bisglycinate is resistant to dietary inhibitors and is therefore a good food fortificant for many matrices. The bioavailability of ferrous bisglycinate is reported to be about four times higher than that of ferrous sulphate and its efficacy is also maintained in premature infants. But iron amino acid chelates are more expensive than ferrous salts. The chelates exhibit low oxidant properties and are environmentally stable, hence they are generally recognized as safe (GRAS). Therefore, iron amino acid chelates offer several advantages over ferrous salts (Nagpal & Choudhury, 2004, Allen, 2002, Bovell-Benjamin et al., 2000, Bagna et al., 2018).
Iron sulphate, iron bisglycinate
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European Commission. Regulation (EU) No 609/2013 of the European Parliament and of the Council of 12 June 2013 on food intended for infants and young children, food for special medical purposes, and total diet replacement for weight control and repealing Council Directive 92/52/EEC, Commission Directives 96/8/EC, 1999/21/EC, 2006/125/EC and 2006/141/EC, Directive 2009/39/EC of the European Parliament and of the Council and Commission Regulations (EC) No 41/2009 and (EC) No 953/2009Text with EEA relevance; 2013. 22 p. [cited 2020 Aug 17]. at: eur-lex.europa.eu/legal-content/EN/ALL/
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