How to increase iron absorption
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Strategies to Increase Iron Absorption
Iron deficiency is a prevalent nutritional issue worldwide, often exacerbated by poor iron absorption from the diet. Various strategies can be employed to enhance iron absorption, ranging from dietary modifications to the timing and composition of iron supplements. This article synthesizes recent research findings on effective methods to increase iron absorption.
Alternate-Day Iron Supplementation
Optimizing Iron Supplementation Schedule
Recent studies suggest that the traditional approach of daily iron supplementation may not be the most effective. Daily dosing can increase serum hepcidin levels, which in turn reduces iron absorption from subsequent doses. Research indicates that providing iron supplements on alternate days significantly improves iron absorption compared to consecutive daily dosing. In a study involving iron-depleted women, alternate-day supplementation resulted in higher cumulative fractional and total iron absorption compared to daily supplementation1.
Dietary Enhancements
Incorporating Meat and Ascorbic Acid
Adding certain foods to meals can significantly enhance non-heme iron absorption. For instance, incorporating meat, which contains heme iron, can increase non-heme iron absorption from plant-based meals. Similarly, ascorbic acid (vitamin C) is a potent enhancer of iron absorption. Studies have shown that adding ascorbic acid to meals can increase iron absorption by up to twofold2 7. For example, adding 65 mg of ascorbic acid from cauliflower or 50 mg of pure ascorbic acid to a meal significantly increased iron absorption2.
Prebiotics and Probiotics
Prebiotics such as galacto-oligosaccharides (GOS) and fructo-oligosaccharides (FOS) have been shown to enhance iron absorption when co-administered with iron supplements. In iron-depleted women, GOS and FOS increased iron absorption by approximately 50% from a 100 mg iron dose3 6. Additionally, probiotics like Lactobacillus plantarum 299v can also boost iron absorption from iron-fortified foods. A study demonstrated that adding this probiotic to a fruit drink increased iron absorption by about 50%4.
Avoiding Inhibitors
Certain dietary components can inhibit iron absorption. Polyphenols found in tea and coffee, as well as phytates in whole grains and legumes, can significantly reduce iron absorption. To mitigate this, it is recommended to consume tea and coffee between meals rather than during meals. Additionally, consuming foods rich in ascorbic acid or meat can help counteract the inhibitory effects of these compounds7.
Genetic Engineering and Fortification
Biofortified Foods
Genetic engineering approaches have been explored to increase the iron content and bioavailability in staple foods like rice. By introducing genes that increase iron content and reduce phytic acid levels, researchers have developed rice varieties that can significantly improve iron nutrition in populations reliant on rice as a staple food8.
Fortification with Enhancers
Fortifying foods with iron along with enhancers like ascorbic acid or Na2EDTA can also improve iron absorption. For example, increasing the ascorbic acid content in a fortified school breakfast meal significantly enhanced iron absorption in children9.
Timing and Composition of Iron Supplements
Morning Dosing and Ascorbic Acid
The timing of iron supplementation can influence its absorption. Taking iron supplements in the morning, away from meals, and with an ascorbic acid-rich beverage like orange juice, can maximize iron absorption. A study found that consuming a 100 mg iron dose with orange juice in the morning resulted in a fourfold increase in iron absorption compared to taking it with coffee or breakfast10.
Conclusion
Enhancing iron absorption involves a multifaceted approach, including optimizing supplementation schedules, incorporating dietary enhancers, avoiding inhibitors, and utilizing biofortified foods. By implementing these strategies, individuals can significantly improve their iron status and mitigate the risks associated with iron deficiency.
Sources and full results
Most relevant research papers on this topic
Iron absorption from oral iron supplements given on consecutive versus alternate days and as single morning doses versus twice-daily split dosing in iron-depleted women: two open-label, randomised controlled trials.
Oral iron supplements given alternate days and as single morning doses have better iron absorption than those given daily or split doses in iron-depleted women.
RCT
Highly CitedImprovement of iron nutrition in developing countries: comparison of adding meat, soy protein, ascorbic acid, citric acid, and ferrous sulphate on iron absorption from a simple Latin American-type of meal.
Adding meat, soy protein, ascorbic acid, and ferrous sulphate to a Latin American meal can increase iron absorption, with the choice depending on factors like cost.
Non-RCTHighly CitedPrebiotic Galacto-oligosaccharides and Fructo-oligosaccharides, but not Acacia Gum, Increase Iron Absorption from a Single High-dose Ferrous Fumarate Supplement in Iron-depleted Women.
Prebiotic galacto-oligosaccharides and fructo-oligosaccharides, but not acacia gum, significantly increase iron absorption from a 100mg oral iron dose in iron-depleted women, potentially improving iron absorption.
RCT
Very Rigorous JournalProbiotic strain Lactobacillus plantarum 299v increases iron absorption from an iron-supplemented fruit drink: a double-isotope cross-over single-blind study in women of reproductive age
Adding probiotic strain Lactobacillus plantarum 299v to an iron-supplemented fruit drink can increase iron absorption by approximately 50% in women of reproductive age.
RCTVery Rigorous JournalHighly CitedVitamin A and beta-carotene can improve nonheme iron absorption from rice, wheat and corn by humans.
Vitamin A and beta-carotene improve iron absorption from rice, wheat, and corn, potentially preventing the inhibitory effect of phytates and polyphenols on iron absorption.
Non-RCTHighly CitedThe Effect of Prebiotics On Human Iron Absorption: A Review.
Prebiotics can enhance iron absorption, with the most convincing evidence found in adult women with low iron stores and anemic infants.
Systematic ReviewVery Rigorous JournalEffect of Tea and Other Dietary Factors on Iron Absorption
Consuming tea between meals and simultaneously consuming ascorbic acid, meat, fish, and poultry can enhance iron absorption, reducing iron deficiency risk.
Highly CitedGenetic engineering approaches to improve the bioavailability and the level of iron in rice grains
High phytase rice, with increased iron content and rich in cysteine-peptide, has the potential to greatly improve iron nutrition in rice-eating populations.
Highly CitedImproving iron absorption from a Peruvian school breakfast meal by adding ascorbic acid or Na2EDTA.
Increasing ascorbic acid content in school breakfasts significantly improves iron absorption, while increasing Na2EDTA's molar ratio to fortification iron has no effect on iron absorption.
Non-RCTHighly CitedEffect of dietary factors and time of day on iron absorption from oral iron supplements in iron deficient women
Consuming iron supplements in the morning, away from meals or coffee, and with an ascorbic acid-rich food or beverage increases iron absorption by 4-fold in iron deficient women.
Non-RCT