The international review journal Advances of Nutrition highlights the IAEA’s role in combatting micronutrient malnutrition over the past two decades. The article presents a comprehensive review of stable isotope methods and their application to nutrition programming by assessing the efficacy and effectiveness of programmes addressing micronutrient deficiencies. It explains how the isotope techniques are used to evaluate the bio-efficacy of provitamin A carotenoids, the status of vitamin A and the bioavailability of iron and zinc. Stable isotope–labelled tracers function as safe, nonradioactive tools to track micronutrients in the body in a quantitative manner because the absorption, distribution, metabolism, and excretion of the tracer are assumed to be similar to unlabelled vitamins or minerals.
For example, the Retinol Isotope Dilution (RID) technique is the most accurate technique available for the assessment of vitamin A status from deficiency to toxicity in a diverse range of populations, since it allows quantitative evaluation of the total vitamin A body stores using 2H- or 13C-labeled retinyl acetate. In Zambia, total body retinol stores were estimated before and after feeding children maize biofortified with β-carotene to determine if vitamin A reserves were improved by the intervention. The RID technique is continuously evolving as analytical techniques advance. Currently the focus is on adapting the RID technique for accessibility and ease of use in low-income regions for large-scale population surveys, as well as making the method more field-friendly and confirming its applicability in diverse populations. Iron and zinc stable isotopes can be used to determine bioavailability and measure efficiency of absorption of iron and zinc from fortified and biofortified foods. For example, iron isotopes have been valuable in recommending appropriate fortificants for foods and defining the interaction with inhibitors and enhancers of absorption.
Micronutrient deficiencies, especially vitamin A, iron and zinc, can be addressed through public health interventions. These deficiencies occur when most of the diet is comprised of nutrient-poor, high carbohydrate staple foods, as is the situation for example in many African countries, where more than 50% of daily calories come from staple grains, roots and tubers. Strategies such as food fortification and biofortification with provitamin A, vitamin A, iron and zinc in low- and middle-income countries have the potential to contribute to sustainable solutions in that regard. These approaches decrease the need for direct nutritional supplementation for vulnerable groups such as women of reproductive age, children and infants, which is expensive and requires continuous financial and human resource inputs to ensure wide coverage and success of the intervention.
The IAEA has fostered the more widespread use of stable isotope techniques in Member States through its Technical Cooperation Programme by building and strengthening capacities for evidence-based nutrition programming using stable isotope and related techniques and in encouraging and assisting the development of and research on stable isotope techniques through Coordinated Research Projects.
The IAEA will organize an international symposium in cooperation with WHO and UNICEF to address the urgent need of “Understanding the Double Burden of Malnutrition for Effective Interventions” from 10-13 December 2018. Micronutrient deficiencies, particularly in connection with obesity, will be discussed among many other topics.
Track our updates to the conference on social media under the hashtag #DBMal.
More information is available on the Symposium website.
