IAEA Technical Meeting

A focus on the Role of Stable Isotope Techniques in Evaluating Food-based Approaches to Improve Diet Quality 

Article by Victor Owino and Cornelia Loechl, IAEA

Climate change may lead to lower soil quality hence decreased plant nutrient density alongside increased anti-nutritional factors, elevated starch content and reduced micronutrient bioavailability. Climate change is further associated with poor sanitation and hygiene which is likely to lead to diarrhea, environmental enteric dysfunction and food contamination with microbial toxins (e.g. aflatoxins). COVID-19 on the other hand has had negative impact on food distribution, choice and access while limiting physical activity.

Nutrition, health and agronomy professionals from over 30 organizations including UN Agencies, CGIARs, government agencies, the private sector, universities and research institutions came together to attend a virtual Technical Meeting organized by the IAEA from 19^th -21^st October 2020. UNSCN’s Coordinator, Stineke Oenema, provided an overview linking the global and local factors which impact on diets and nutrition to ensure all participants, who came from a broad range of backgrounds, began the meeting with a sound foundational knowledge of the nutrition situation. Discussions focused on how stable isotopes and related nuclear techniques can be used to evaluate food-based approaches to improve diet quality in the face of rapidly changing food systems, climate change and the COVID-19 pandemic.

The meeting underscored the need for multi-disciplinary and multi-sectoral collaboration to address diet quality from a food systems and value chain approach in order to fully understand the pathways that underpin the link between food systems, diet quality and human health outcomes. Bio- and agro-diversity can be of dual benefit, providing resilience against climate change while supporting healthier diets and nutrition.

Results from controlled efficacy studies on interventions such as biofortification, food fortification and consumption of a diverse diet show beneficial impacts on nutritional and health outcomes. However, this is a growing research field which requires more implementation research to fully understand their effectiveness in the context of a changing a climate and to effectively scale up the interventions in different contexts. Additionally, there is need to simultaneously utilize hitherto unknown or underutilized foods such as edible insects with low carbon footprint. The key role that animal source foods play on child growth and development was underscored, especially in contexts where plant-based diets are the norm. However, consideration needs to be given to multiple trade-offs including, environmental footprint, crop yield versus grain content, grain protein versus starch content and grain protein versus anti-nutritional content associated with these innovations. Nutrition sensitive programming such as cash transfers, school meals, social protection, general food assistance, smallholder farming initiatives and ensuring good hygiene and sanitation will continue to gain significance.

The difficulties in measuring diet quality which is often defined based on adequate intake, specific recommendations or perceived health benefits were also discussed. Current diet quality measurement tools include the Minimum Dietary Diversity Indicator for Women (MDD-W) developed by the FAO that comprises 10 food groups, the consumption of which is correlated with the probability of meeting the intake requirements of 11 micronutrients. Additionally, the WFP supported ‘Fill the Nutrient Gap’ (FNG) analysis can assess the magnitude and nature of the nutrient gap by age groups and identify the main drivers including accessibility, physical access, affordability and demand. The Evidence and Gap Map (EGM) developed by the Innovative Metrics, Tools and Methods in Agriculture-Nutrition Research (IMMANA) consists of twelve elements spanning the entire foods systems continuum from seed to nutrition and health.

Non-invasive and accurate stable isotope and related nuclear techniques have been applied to assess various dimensions of diet quality including breastfeeding practices, micronutrient status and bioavailability, protein quality and how sanitary conditions influence gut function and nutrient absorption. In the food systems value chain nuclear techniques can be used in plant breeding, soil and water management, and assessment of crop nutrient composition, nutrient absorption and related nutritional and health outcomes such as body composition. For example, the IAEA is supporting seven countries to use a dual isotope (deuterium and 13C) technique to assess true amino acid digestion from commonly consumed legume crops in the framework of a coordinated research project (CRP). Results from this CRP can enrich the FAO database on true protein digestion and aid future discussions on generating evidence to inform protein requirements. Regarding the link between sanitation and health outcomes, it was noted that the IAEA is already supporting Member States through a CRP to develop a stable isotope (13C-Sucrose) based diagnostic tool for EED. Other IAEA-driven efforts include understanding vitamin A status in the context of multiple interventions to combat vitamin A deficiency and development of biomarkers of sugar intake and linking to risk of NCD’s.

Finally, the meeting recognized the imperative to take advantage of the renewed global interest on food systems and diet quality. Global initiatives and events such as the Committee on World Food Security, the UN Environmental Assembly focusing on water, energy and food nexus, the biodiversity conference of parties (COP), the UN Food Systems Summit 2021, the climate COP and the Nutrition for Growth event planned for 2021 provide an opportunity to place the diet quality agenda at the very top.  Partnerships and collaborations will be needed especially in generating nutrient composition and absorption databases.

1. What is the impact of climate change on crop nutrient density and bioavailability; are there particularly sensitive nutrients and how does anti-nutrient content vary?
2. How does dietary intake vary in specific population groups?
3. What is the role of edible insects in the food systems value chain and what is the implication on environmental footprint and food waste?
4. What is the linkage between climate change, sanitary conditions and diet quality and health; what is the role of environmental enteric dysfunction, diarrhoea and mycotoxins?
5. What is the minimum set of indicators that can be used to measure the entire food systems continuum (from food production to health including functional outcomes)?
6. How can we make nutrition and health-related research useful to policy makers?
7. How can we better mobilise resources to fund the unprecedented interest in diet quality?
8. What is the effect of climate change on the women’s nutrition and health outcomes and their ability to care for children?
9. What are the implications of climate change on diet quality in the context of population displacement, urbanization, and shifting consumer behaviour?
10. What partnerships and collaborations are needed; how can other sectors, disciplines be roped in to comprehensively understand the food systems continuum?