Bioavailability of Iron in Dietary Sources

Iron is an essential micronutrient required for oxygen transport, energy metabolism and cellular function. Dietary iron exists in two main forms: haem iron, derived from animal tissues, and non-haem iron, found predominantly in plant-based foods. Haem iron is generally absorbed more efficiently, whereas non-haem iron bioavailability is highly dependent on dietary context. Enhancers such as ascorbic acid and certain organic acids can reduce ferric to ferrous iron, increasing solubility and uptake, while inhibitors including phytate, polyphenols and some proteins bind iron and limit absorption. Globally, inadequate iron bioavailability contributes to anaemia and impaired cognitive and physical performance, particularly in vulnerable groups. Research has focused on agronomic, genetic and processing strategies to boost iron concentration in staple crops and to overcome inhibitory food matrices. Interventions range from conventional and biofortification breeding to flour particle size reduction, enzymatic phytate degradation and incorporation of iron-absorption enhancers. Such approaches aim to deliver cost-effective, culturally acceptable solutions to improve iron status and public health at scale.

Research from Nature Portfolio

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Bioavailability of Iron in Dietary Sources publication trend

The graph below shows the total number of articles in bioavailability of iron in dietary sources across all publications each year (not limited to Nature Index journals).

Technical terms

Bioavailability: The proportion of an ingested nutrient that is absorbed and utilised for physiological functions.

Bioaccessibility: The fraction of a nutrient released from the food matrix during digestion and thus available for absorption.

Phytate: A naturally occurring compound in seeds and grains that chelates minerals, notably iron, reducing their solubility and uptake.

Non-haem iron: Iron in the ferric or ferrous state found in plant-based foods, whose absorption is influenced by dietary enhancers and inhibitors.

Caco-2 cells: A human intestinal epithelial cell line used in vitro to model and quantify nutrient absorption mechanisms.

References

1. Micronization of wholewheat flour increases iron bioavailability from hydrothermally processed wheat flour dough. Food Research International (2024).
2. Edible Halophytes with Functional Properties: In Vitro Protein Digestibility and Bioaccessibility and Intestinal Absorption of Minerals and Trace Elements from Australian Indigenous Halophytes. Molecules (2023).
3. Strategies to increase the bioaccessibility and bioavailability of iron and zinc from cereal products.. Proceedings of The Nutrition Society (2023).