This review makes a case for taking an integrated ‘food systems’ approach to explore the links between health and sustainability rather than treating them as separate topics. Unlike more linear ‘farm-to-fork’ conceptions, a systems approach emphasises the links between domains and sectors, helping avoid perverse effects where an intervention at one point in the system can have unanticipated consequences at other points. Adopting this approach, the review argues that food security and sustainability are as much a socio-cultural as a technical challenge requiring the combined forces of researchers from the natural and social sciences together with a range of stakeholders from government, business and civil society. Meeting the twin challenges of health and sustainability will require changes to intensive food production systems, dietary change and reductions in current levels of food waste. The review explores why dietary practices are so resistant to change seeking alternatives to the deficit thinking that pervades much advice on ‘healthy eating’. It explores the locus of responsibility for food system change, emphasising the asymmetrical power relations that shape contemporary dietary choices. The review includes an example of food system research, the H3 project (healthy soil, healthy food, healthy people), which seeks to transform UK food systems ‘from the ground up’, adopting the principles outlined in the body of the review.

Nutrition scientists are currently facing a substantial challenge: to feed the world population sustainably and ethically while supporting the health of all individuals, animals and the environment. The Nutrition Society of Australia's 2022 Annual Scientific meeting theme ‘Sustainable nutrition for a healthy life’ was a timely conference focusing on the environmental impact of global, national and local food systems, how nutrition science can promote sustainable eating practices while respecting cultural and culinary diversity and how to ensure optimal nutrition throughout life to prevent and manage chronic diseases. Comprehensive, diverse, collaborative and forward-thinking research was presented in a 3 d programme of keynote presentations, oral and poster sessions, breakfast and lunch symposiums, ending with a panel discussion to answer the question of how we can best achieve a nutritious food supply that supports human and planetary health. We concluded that this complex issue necessitates coordinated efforts and multi-faceted responses at local, national and global levels. Collaboration among consumers, scientists, industry and government using a systems approach is vital for finding solutions to this challenge.

In this review, the relevance of selenium (Se) to viral disease will be discussed paying particular attention to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and coronavirus disease (COVID-19). Se, the active centre in selenoproteins has an ongoing history of reducing the incidence and severity of viral infections. Host Se deficiency increased the virulence of RNA viruses such as influenza A and coxsackievirus B3, the latter of which is implicated in the development of Keshan disease in north-east China. Significant clinical benefits of Se supplementation have been demonstrated in HIV-1, in liver cancer linked to hepatitis B, and in Chinese patients with hantavirus that was successfully treated with oral sodium selenite. China is of particular interest because it has populations that have both the lowest and the highest Se status in the world. We found a significant association between COVID-19 cure rate and background Se status in Chinese cities; the cure rate continued to rise beyond the Se intake required to optimise selenoproteins, suggesting an additional mechanism. Se status was significantly higher in serum samples from surviving than non-surviving COVID-19 patients. As regards mechanism, SARS-CoV-2 may interfere with the human selenoprotein system; selenoproteins are important in scavenging reactive oxygen species, controlling immunity, reducing inflammation, ferroptosis and endoplasmic reticulum (ER) stress. We found that SARS-CoV-2 significantly suppressed mRNA expression of GPX4, of the ER selenoproteins, SELENOF, SELENOM, SELENOK and SELENOS and down-regulated TXNRD3. Based on the available data, both selenoproteins and redox-active Se species (mimicking ebselen, an inhibitor of the main SARS-CoV-2 protease that enables viral maturation within the host) could employ their separate mechanisms to attenuate virus-triggered oxidative stress, excessive inflammatory responses and immune-system dysfunction, thus improving the outcome of SARS-CoV-2 infection.

Over 30 years ago it was proven beyond doubt that folic acid supplementation of mothers in early pregnancy protects against neural tube defects (NTD) in their babies. Such conclusive scientific evidence led to clear recommendations for women worldwide to take 0⋅4 mg/d folic acid before conceiving and in early pregnancy, but implementing these into effective policy has been problematic. As a result, there has been no change in the incidence of NTD in Ireland, the UK or any other European country over the 25-year period that the current strategy, recommending periconceptional folic acid supplements to women, has been in place. Thus preventable NTD are not being prevented. Notably, in September 2021, the UK government announced that starch is to be fortified with folic acid on a mandatory basis. A similar decision is now urgently needed in Ireland, where rates of NTD are among the highest in the world. A policy of mandatory folic acid fortification of food would be highly effective in preventing NTD because it reaches all women, including those who have not planned their pregnancy. International evidence shows that wherever such a policy has been introduced, it has proved to be effective in reducing rates of NTD in that country. Apart from preventing NTD, the driver of policy in the area, other potential health benefits across the lifecycle can be anticipated from folic acid fortification. Urgent action is needed on implementation of mandatory food fortification with folic acid in Ireland so that mothers and their babies can benefit.

The marketing of foods and non-alcoholic beverages (hereafter: food) high in fats, salt and/or sugar (HFSS) has been strongly implicated in the rising levels of childhood obesity worldwide. Multiple ethical concerns arise from the practice of exposing children to such marketing and efforts to monitor and restrict it through regulatory policies. There is considerable evidence that exposure to powerful food marketing messages affects children's food behaviours in ways that are detrimental to good dietary health. Children are particularly vulnerable to being exploited and deceived by food marketing messages based on their cognitive and developmental immaturity. HFSS food marketing also affects numerous child rights enshrined within the UN Convention on the Rights of the Child (of which the UK is a signatory) including the right to the enjoyment of the highest attainable standard of health. The debate has become somewhat polarised between the public health community's evidence-based assertion that all marketing is inherently exploitative and the rebuttal from food and marketing industry stakeholders that provided the marketing is ‘accurate and truthful’ and there is no ethical need to regulate. This polarisation is reflected in the complexity of policymaking decisions regarding the rationale for mandatory government-led policies or industry self-regulation. There are also ethical considerations inherent in the monitoring of children's food marketing exposure, particularly in the digital sphere, by researchers for the purposes of informing policy design, scope and implementation. This review paper will explore the latest evidence on these issues and consider the implications for public health research, policy, and practice.

The role of early life nutrition's impact on relevant health outcomes across the lifespan laid the foundation for the field titled the developmental origins of health and disease. Studies in this area initially concentrated on nutrition and the risk of adverse cardio-metabolic and cancer outcomes. More recently the role of nutrition in early brain development and the subsequent influence of later mental health has become more evident. Scientific breakthroughs have elucidated two mechanisms behind long-term nutrient effects on the brain, including the existence of critical periods for certain nutrients during brain development and nutrient-driven epigenetic modifications of chromatin. While multiple nutrients and nutritional conditions have the potential to modify brain development, iron can serve as a paradigm to understand both mechanisms. New horizons in nutritional medicine include leveraging the mechanistic knowledge of nutrient–brain interactions to propose novel nutritional approaches that protect the developing brain through better timing of nutrient delivery and potential reversal of negative epigenetic marks. The main challenge in the field is detecting whether a change in nutritional status truly affects the brain's development and performance in human subjects. To that end, a strong case can be made to develop and utilise bioindicators of a nutrient's effect on the developing brain instead of relying exclusively on biomarkers of the nutrient's status.

Obesity and dyslipidaemia are strongly associated with the development of cardiometabolic diseases including CVD, stroke, type 2 diabetes, insulin resistance and non-alcoholic fatty liver disease. While these conditions are preventable, they are leading causes of mortality globally. There is now overwhelming clinical and experimental evidence that these conditions are driven by chronic systemic inflammation, with a growing body of data suggesting that this can be regulated by increasing levels of physical activity and reducing sedentary time. In this review we address the role of macrophage-mediated inflammation on the development of cardiometabolic diseases in individuals with overweight and obesity and how reducing sedentary behaviour and increasing physical activity appears to lessen these pro-inflammatory processes, reducing the risk of developing cardiometabolic diseases. While loss of subcutaneous and visceral fat mass is important for reducing chronic systemic inflammation, the mediating effects of increasing physical activity levels and lowering sedentary time on the development of inflamed adipose tissue also occur independently of changes in adiposity. The message that weight loss is not necessary for the benefits of physical activity in lowering chronic inflammation and improving health should encourage those for whom losing weight is difficult. Additionally, while the health benefits of meeting the recommended physical activity guidelines are clear, simply moving more appears to lower chronic systemic inflammation. Reducing sitting time and increasing light physical activity may therefore provide an alternative, more approachable manner for some with overweight and obesity to become more active, reduce chronic inflammation and improve cardiometabolic health.

Globally, diet quality is poor, with populations failing to achieve national dietary guidelines. Such failure has been consistently linked with malnutrition and poorer health outcomes. In addition to the impact of diet on health outcomes, it is now accepted that what we eat, and the resulting food system, has significant environmental or planetary health impacts. Changes are required to our food systems to reduce these impacts and mitigate the impact of climate change on our food supply. Given the complexity of the interactions between climate change, food and health, and the different actors and drivers that influence these, a systems-thinking approach to capture such complexity is essential. Such an approach will help address the challenges set by the UN 2030 Agenda for sustainable development in the form of the sustainable development goals (SDG). Progress against SDG has been challenging, with an ultimate target of 2030. While the scientific uncertainties regarding diet and public and planetary health need to be addressed, equal attention needs to be paid to the structures and systems, as there is a need for multi-level, coherent and sustained structural interventions and policies across the full food system/supply chain to effect behaviour change. Such systems-level change must always keep nutritional status, including impact on micronutrient status, in mind. However, benefits to both population and environmental health could be expected from achieving dietary behaviour change towards more sustainable diets.