MICA: Creating an open access knowledge hub of nutritional biomarkers for use in global health settings Malnutrition, from either under- or over-nutrition, directly affects one in three people globally making malnutrition, together with diet, by far the biggest risk factors for the global burden of disease. Widespread undernutrition and micronutrient deficiencies lead to poor child growth, impaired mental development and reduced adult labour productivity, while a transition towards a more 'westernised' diet is associated with rising rates of obesity and diet related non-communicable diseases. This under- and over-nutrition often coexists to create a 'double-burden' of malnutrition-related health consequences and, with rapid urbanization and the associated nutrition transition, this double burden is most predominant in many low- and middle-income countries (LMICs).   To advance understanding of links between diet, nutrition and health in LMICs and to develop and evaluate evidence-based programmes and policies, detailed understanding of nutritional status is required. Existing, community-based studies and surveys from LMIC settings often lack detailed data on individual and population-level nutritional status to inform on policy. Data from critical population categories (e.g. infants, children, adolescents, pregnant and lactation women) are often limited to anthropometry and easy-to-assay parameters (e.g. haemoglobin) or single micronutrients (e.g. vitamin A, iodine). This leads to a knowledge gap to describe the nutritional vulnerabilities in these population groups and hence inform on the design of novel interventions.  Modern methods to measure nutritional status have moved away from single nutrient assays requiring relatively large aliquots of blood, access to sample storage facilities, and sophisticated equipment towards 'multiplex' approaches where groups of analytes can be measured in small volumes or on more appropriate matrices, such as dried blood spots. A critical barrier to applying these novel methodologies in LMIC contexts is a lack of easy to access information on their availability and utility and a lack of technical support for the required platforms.  In response to this global need, the aim of this application is to bring together expertise in nutritional biomarkers, to create a freely available, online resource (a 'knowledge hub') to support the accurate and detailed assessment of nutritional status in populations from low- and middle-income countries (LMICs). Through a network of academic and industry experts, we will also identify research gaps, where existing methodologies are not practical for implementation in low resource settings or for use in large, population based research in LMICs. The knowledge hub created will enable and support all nutrition and health related research activities in LMICs contributing towards a greater depth of knowledge on the nutritional status of populations in these settings. The longer-term vision of this work is to establish centres of excellence in nutritional assessment methodologies in LMIC settings. Supported by a network of academic, technical and industry experts, these centres will support academic and programmatic research in LMICs, enabling a more comprehensive understanding of the relationship between diet, nutrition and health. Further, where research gaps are identified, we will work with academic and industry partners to develop novel assays to meet the research needs for nutrition and health research globally. The Global Challenges Research Fund (GCRF) supports cutting-edge research to address challenges faced by developing countries. The fund addresses the UN sustainable development goals. It aims to maximise the impact of research and innovation to improve lives and opportunity in the developing world.