Many nutrients have powerful immunomodulatory actions with the potential to alter susceptibility to coronavirus disease 2019 (COVID-19) infection, progression to symptoms, likelihood of severe disease, and survival. The aim was to review the latest evidence on how malnutrition across all its forms (under- and overnutrition and micronutrient status) may influence both susceptibility to, and progression of, COVID-19. We synthesized information on 13 nutrition-related components and their potential interactions with COVID-19: overweight, obesity, and diabetes; protein-energy malnutrition; anemia; vitamins A, C, D, and E; PUFAs; iron; selenium; zinc; antioxidants; and nutritional support. For each section we provide: 1) a landscape review of pertinent material; 2) a systematic search of the literature in PubMed and EMBASE databases, including a wide range of preprint servers; and 3) a screen of 6 clinical trial registries. All original research was considered, without restriction to study design, and included if it covered: 1) severe acute respiratory syndrome coronavirus (CoV) 2 (SARS-CoV-2), Middle East respiratory syndrome CoV (MERS-CoV), or SARS-CoV viruses and 2) disease susceptibility or 3) disease progression, and 4) the nutritional component of interest. Searches took place between 16 May and 11 August 2020. Across the 13 searches, 2732 articles from PubMed and EMBASE, 4164 articles from the preprint servers, and 433 trials were returned. In the final narrative synthesis, we include 22 published articles, 38 preprint articles, and 79 trials. Currently there is limited evidence that high-dose supplements of micronutrients will either prevent severe disease or speed up recovery. However, results of clinical trials are eagerly awaited. Given the known impacts of all forms of malnutrition on the immune system, public health strategies to reduce micronutrient deficiencies and undernutrition remain of critical importance. Furthermore, there is strong evidence that prevention of obesity and type 2 diabetes will reduce the risk of serious COVID-19 outcomes. This review is registered at PROSPERO as CRD42020186194.

Children with moderate acute malnutrition (MAM) have an increased risk of mortality, infections and impaired physical and cognitive development compared to well-nourished children. In parts of Ethiopia not considered chronically food insecure there are no supplementary feeding programmes (SFPs) for treating MAM. The short-term outcomes of children who have MAM in such areas are not currently described, and there remains an urgent need for evidence-based policy recommendations. We defined MAM as mid-upper arm circumference (MUAC) of ≥11.0cm and <12.5cm with no bilateral pitting oedema to include Ethiopian government and World Health Organisation cut-offs. We prospectively surveyed 884 children aged 6–59 months living with MAM in a rural area of Ethiopia not eligible for a supplementary feeding programme. Weekly home visits were made for seven months (28 weeks), covering the end of peak malnutrition through to the post-harvest period (the most food secure window), collecting anthropometric, socio-demographic and food security data. By the end of the study follow up, 32.5% (287/884) remained with MAM, 9.3% (82/884) experienced at least one episode of SAM (MUAC <11cm and/or bilateral pitting oedema), and 0.9% (8/884) died. Only 54.2% of the children recovered with no episode of SAM by the end of the study. Of those who developed SAM half still had MAM at the end of the follow up period. The median (interquartile range) time to recovery was 9 (4–15) weeks. Children with the lowest MUAC at enrolment had a significantly higher risk of remaining with MAM and a lower chance of recovering. Children with MAM during the post-harvest season in an area not eligible for SFP experience an extremely high incidence of SAM and a low recovery rate. Not having a targeted nutrition-specific intervention to address MAM in this context places children with MAM at excessive risk of adverse outcomes. Further preventive and curative approaches should urgently be considered.

Severe acute malnutrition (SAM) is a major global health problem affecting some 16.9 million children under five. Little is known about what happens to children 6–24 months post-discharge as this window often falls through the gap between studies on SFPs and those focusing on longer-term effects. A protocol was registered on PROSPERO (PROSPERO 2017:CRD42017065650). Embase, Global Health and MEDLINE In-Process and Non-Indexed Citations were systematically searched with terms related to SAM, nutritional intervention and follow-up between June and August 2017. Studies were selected if they included children who experienced an episode of SAM, received a therapeutic feeding intervention, were discharged as cured and presented any outcome from follow-up between 6–24 months later. 3,691 articles were retrieved from the search, 55 full-texts were screened and seven met the inclusion criteria. Loss-to-follow-up, mortality, relapse, morbidity and anthropometry were outcomes reported. Between 0.0% and 45.1% of cohorts were lost-to-follow-up. Of those discharged as nutritionally cured, mortality ranged from 0.06% to 10.4% at an average of 12 months post-discharge. Relapse was inconsistently defined, measured, and reported, ranging from 0% to 6.3%. Two studies reported improved weight-for-height z-scores, whilst three studies that reported height-for-age z-scores found either limited or no improvement. Overall, there is a scarcity of studies that follow-up children 6–24 months post-discharge from SAM treatment. Limited data that exists suggest that children may exhibit sustained vulnerability even after achieving nutritional cure, including heightened mortality and morbidity risk and persistent stunting. Prospective cohort studies assessing a wider range of outcomes in children post-SAM treatment are a priority, as are intervention studies exploring how to improve post-SAM outcomes and identify high-risk children.

Mounting evidence suggests that nutritional exposures during pregnancy influence the fetal epigenome, and that these epigenetic changes can persist postnatally, with implications for disease risk across the life course. We review human intergenerational studies using a three-part search strategy. Search 1 investigates associations between preconceptional or pregnancy nutritional exposures, focusing on one-carbon metabolism, and offspring DNA methylation. Search 2 considers associations between offspring DNA methylation at genes found in the first search and growth-related, cardiometabolic and cognitive outcomes. Search 3 isolates those studies explicitly linking maternal nutritional exposure to offspring phenotype via DNA methylation. Finally, we compile all candidate genes and regions of interest identified in the searches and describe their genomic locations, annotations and coverage on the Illumina Infinium Methylation beadchip arrays. We summarize findings from the 34 studies found in the first search, the 31 studies found in the second search and the eight studies found in the third search. We provide details of all regions of interest within 45 genes captured by this review. Many studies have investigated imprinted genes as priority loci, but with the adoption of microarray-based platforms other candidate genes and gene classes are now emerging. Despite a wealth of information, the current literature is characterized by heterogeneous exposures and outcomes, and mostly comprise observational associations that are frequently underpowered. The synthesis of current knowledge provided by this review identifies research needs on the pathway to developing possible early life interventions to optimize lifelong health.

Maternal anaemia prevalence in low‐income countries is unacceptably high. Our research explored the individual‐, family‐ and community‐level factors affecting antenatal care uptake, iron folic acid (IFA) intake and consumption of micronutrient‐rich diets among pregnant women in the plains of Nepal. We discuss how these findings informed the development of a home visit and community mobilisation intervention to reduce anaemia in pregnancy. We used a qualitative methodology informed by the socio‐ecological framework, conducting semi‐structured interviews with recently pregnant women and key informants, and focus group discussions with mothers‐in‐law and fathers. We found that harmful gender norms restricted women's access to nutrient‐rich food, restricted their mobility and access to antenatal care. These norms also restricted fathers' role to that of the provider, as opposed to the caregiver. Pregnant women, mothers‐in‐law and fathers lacked awareness about iron‐rich foods and how to manage the side effects of IFA. Fathers lacked trust in government health facilities affecting access to care and trust in the efficacy of IFA. Our research informed interventions by (1) informing the development of intervention tools and training; (2) informing the intervention focus to engaging mothers‐in‐law and men to enable behaviour change; and (3) demonstrating the need to work in synergy across individual, family and community levels to address power and positionality, gender norms, trust in health services and harmful norms. Participatory groups and home visits will enable the development and implementation of feasible and acceptable strategies to address family and contextual issues generating knowledge and an enabling environment for behaviour change.

Childhood wasting and stunting affect large numbers of children globally. Both are important risk factors for illness and death yet, despite the fact that these conditions can share common risk factors and are often seen in the same child, they are commonly portrayed as relatively distinct manifestations of undernutrition. In 2014, the Wasting and Stunting project was launched by the Emergency Nutrition Network. Its aim was to better understand the complex relationship and associations between wasting and stunting and examine whether current separations that were apparent in approaches to policy, financing, and programs were justified or useful. Based on the project's work, this article aims to bring a wasting and stunting lens to how research is designed and financed in order for the nutrition community to better understand, prevent, and treat child undernutrition. Discussion of lessons learnt focuses on the synergy and temporal relationships between children's weight loss and linear growth faltering, the proximal and distal factors that drive diverse forms of undernutrition, and identifying and targeting people most at risk. Supporting progress in all these areas requires research collaborations across interest groups that highlight the value of research that moves beyond a focus on single forms of undernutrition, and ensures that there is equal attention given to wasting as to other forms of malnutrition, wherever it is present.