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Iron and Zinc Bioavailability

Iron and zinc deficiencies are common nutritional deficiencies in the world and contribute substantially to mortality and disability. Both trace elements are most bioavailable from the same foods and at the same time their absorption is inhibited by many of the same dietary substances. For that reason, iron and zinc deficiencies may occur simultaneously. Iron deficiency can impair cognitive development, immunity, work capacity and childbirth, whereas deficiencies in dietary zinc result in high rates of stunting, sexual maturation, reproduction and healing. Only small fractions from dietary intakes of iron and zinc can be absorbed and utilized. The absorption is substantially influenced by the chemical form and by other dietary components ingested at the same time, such as phytate. As a result, information on bioavailability from foods, diets, and fortificants is crucial in the development of interventions based on food fortification and dietary diversification. Isotopic techniques have been instrumental in determining the bioavailability and measuring efficiency of absorption of iron and zinc from fortified and biofortified foods as well as identifying enhancers and inhibitors of absorption to improve diets. The IAEA provides information on the theoretical background and practical application of state of the art methodology for iron and zinc bioavailability assessment using stable isotopes.


IAEA Publications

Assessment of Iron Bioavailability in Humans Using Stable Iron Isotope Techniques IAEA Human Health Series No. 21; 2012, 78 pp. International Atomic Energy Agency, Vienna, Austria.
This publication on the assessment of iron bioavailability was developed as part of the IAEA’s continuing efforts to transfer knowledge and technology in the use of stable isotope techniques in nutrition. It provides information on the theoretical background and practical application of state of the art methodology to measure human iron absorption and dietary iron bioavailability using stable (non-radioactive) isotopes. These techniques can be used to guide fortification and food based strategies to combat iron deficiency, which remains unacceptably high among infants, children and women of childbearing age in developing countries.

Assessment of Zinc Metabolism in Humans Using Stable Zinc Isotope Techniques IAEA Human Health Series No. 35; 2018; 115 pp. International Atomic Energy Agency, Vienna, Austria.
This publication is part of the lAEA's continuing efforts to transfer technology and to contribute to capacity building by providing information on the theoretical background and practical application of state of the art methodologies for assessing human zinc metabolism to better understand absorption, dietary bioavailability and nutritional requirements. It reviews the role of zinc in human nutrition and the application of stable isotope techniques to evaluate nutritional interventions. Advice is given on planning a study, administering isotopes, preparing and analysing samples, and calculating physiological end points. The publication was developed with input from international experts and is intended for nutritionists, analytical chemists and other professionals interested in the application of stable isotope techniques to evaluate human zinc nutrition and metabolism.


Additional Resources

Spreadsheet for Zinc enrichment calculation


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