With growing and ageing populations, the incidence of dementia is expected to triple globally by 2050. In the absence of effective drugs to treat or reverse the syndrome, dietary approaches which prevent or delay disease onset have considerable population health potential. Prospective epidemiological studies and mechanistic insight from experimental models strongly support a positive effect of a high fish and long chain n-3 fatty acid (EPA and DHA) intake on a range of cognitive outcomes and dementia risk, with effect sizes equivalent to several years of ageing between the highest and lowest consumers. As reviewed here, an effect of EPA and DHA on neuroinflammation and oxylipin production is likely to in part mediate the neurophysiological benefits. However, randomised controlled trials (RCTs) with EPA and DHA supplementation have produced mixed findings. Insight into the likely modulators of response to intervention and factors which should be considered for future RCTs are given. Furthermore, the impact of APOE genotype on disease risk and response to EPA and DHA supplementation is summarised. The prevalence of dementia is several-fold higher in APOE4 females (about 13% Caucasian populations) relative to the general population, who are emerging as a subgroup who may particularly benefit from DHA intervention, prior to the development of significant pathology.

Lower household income has been consistently associated with poorer diet quality and poorer dietary health outcomes. Households experiencing poverty find themselves unable to afford enough food, and the food that they can afford is often poor quality, energy dense and low in nutrients. However, the relationship between diet, poverty and health is complex. Not everyone on a low income has a poor diet. Poverty is about more than low incomes and it is not a uniform experience. Particular aspects of the experience of poverty have implications for diet and dietary health. It is increasingly apparent that uncertainty is one of those aspects. Recession, welfare policy, employment trends and widening inequality have created more uncertainty for those on low incomes. In the context of heightened uncertainty, all aspects of household food provisioning – including budgeting, shopping, storage, meal planning and cooking – are more difficult and sometimes impossible. This review will draw on research about food practices and dietary health in low-income neighbourhoods to explore the ways in which experiences of prolonged uncertainty shape dietary practices and impact health and well-being.

A Nutrition Society member-led meeting was held online on 18th January 2021 to discuss the role of observational studies in developing public health policy and dietary guidelines. In addition, participants debated media reporting of observational studies and the implications for public perception and trust in science. Speakers outlined the benefits of observational studies and how they fit within the suite of research tools available for estimating dietary intakes and determining their impact on health and disease risk. However, there are clear limitations, such as conscious and unconscious bias, measurement error, confounding and representativeness of populations. Researchers can overcome some of these issues with careful design, awareness of inter-individual variation, open and transparent reporting of findings, and hypothesis-driven statistical analysis to avoid multiple testing errors. Although there is evidence that data provided by nutritional epidemiology can be misleading, strong and thoughtful methodology including pre-registration, risk of bias assessment, awareness of confounders, and evidence grading can minimise potential bias, particularly when conducting systematic reviews. Translation of relative risk into population health impact is important and feeds into the need for responsible lay communication of results via mass media, especially regarding assumptions about cause and effect. Although use of mass media can bring benefits to academia, responsible dissemination is essential and starts with the press release. In conclusion, nutritional epidemiology is an important tool for exploring the risk/benefits of dietary patterns and contributing to health improvement via dietary guidelines, evidence-based policy and responsible lay communication provided its limitations are fully understood.

Dietary patterns (DP) rich in plant foods are associated with improved health and reduced non-communicable disease risk. In October 2021, the Nutrition Society hosted a member-led conference, held online over 2 half days, exploring the latest research findings examining plant-rich DP and health. The aim of the present paper is to summarise the content of the conference and synopses of the individual speaker presentations are included. Topics included epidemiological analysis of plant-rich DP and health outcomes, the effects of dietary interventions which have increased fruit and vegetable (FV) intake on a range of health outcomes, how adherence to plant-rich DP is assessed, the use of biomarkers to assess FV intake and a consideration of how modifying behaviour towards increased FV intake could impact environmental outcomes, planetary health and food systems. In conclusion, although there are still considerable uncertainties which require further research, which were considered as part of the conference and are summarised in this review, adopting a plant-rich DP at a population level could have a considerable impact on diet and health outcomes, as well as planetary health.

The purpose of this article is to describe a series of recent studies from the authors and many of their colleagues aimed at improving the food environments of adolescents in the Netherlands and thereby improving their food choices. These studies are performed in the wider context of national and local strategies for the prevention of overweight and obesity in the Netherlands. Interventions were developed with local stakeholders and carried out in schools, supermarkets and low-income neighbourhoods. We conclude that current national policies in the Netherlands are largely ineffective in reducing the prevalence of overweight and obesity. Local integrated programmes in the Netherlands, however, seem to result in a reduction of overweight, especially in low-income neighbourhoods. It is impossible to say which elements of such an integrated approach are effective elements on their own. We found very little evidence for the effectiveness of separate interventions aimed at small changes in the food environment. This suggests that such interventions are only effective in combination with each other and in a wider systems approach. Future studies are needed to further develop the practical methodology of implementation and evaluation of systems science in combination with participatory action research.

The aim of this review is to provide an overview of how person-specific interactions between diet and the gut microbiota could play a role in affecting diet-induced weight loss responses. The highly person-specific gut microbiota, which is shaped by our diet, secretes digestive enzymes and molecules that affect digestion in the colon. Therefore, weight loss responses could in part depend on personal colonic fermentation responses, which affect energy extraction of food and production of microbial metabolites, such as short-chain fatty acids (SCFAs), which exert various effects on host metabolism. Colonic fermentation is the net result of the complex interplay between availability of dietary substrates, the functional capacity of the gut microbiome and environmental (abiotic) factors in the gut such as pH and transit time. While animal studies have demonstrated that the gut microbiota can causally affect obesity, causal and mechanistic evidence from human studies is still largely lacking. However, recent human studies have proposed that the baseline gut microbiota composition may predict diet-induced weight loss-responses. In particular, individuals characterised by high relative abundance of Prevotella have been found to lose more weight on diets rich in dietary fibre compared to individuals with low Prevotella abundance. Although harnessing of personal diet–microbiota interactions holds promise for more personalised nutrition and obesity management strategies to improve human health, there is currently insufficient evidence to unequivocally link the gut microbiota and weight loss in human subjects. To move the field forward, a greater understanding of the mechanistic underpinnings of personal diet–microbiota interactions is needed.

Malnutrition is common among older adults and is associated with a progressive decline in overall health and increased mortality. With a rapidly ageing population, the detection, prevention and management of malnutrition require urgent attention within health service planning and delivery. Routine screening for malnutrition among older adults in community settings, which addresses aetiological as well as phenotypic factors, is considered an important step for prevention and early intervention. The aim of this review is to summarise current malnutrition screening literature and highlight research that seeks to understand and address community-based approaches to malnutrition screening and management. Key healthcare professionals (HCPs) that encounter community-dwelling older adults include general practitioners (GPs), community-based nurses, community pharmacists and a range of other health and social care professionals including dietitians, physiotherapists, speech and language therapists, and occupational therapists. The key barriers to implementing screening in primary care include lack of knowledge about malnutrition among non-dietetic HCPs, lack of resources allocated to managing malnutrition, lack of access to dietetic services, and poor GP knowledge about oral nutritional supplement prescribing. In addition, older adults have poor insight into the clinical condition and the associated negative health implications. Investment in education among HCPs and public awareness is required, as well as accompanying resources to successfully implement malnutrition screening programmes for community-dwelling older adults.

Emotional overeating is a process that is particularly relevant to people within the binge spectrum of eating disorders. Approximately a third of people with overweight share this phenotype. In addition, this behaviour may occur in neurodevelopmental disorders (attention-deficit hyperactivity disorder (ADHD)) and other psychiatric disorders. The biopsychosocial underpinnings of emotional eating include a genetic vulnerability to a higher weight and various cognitive and emotional traits. The environment also plays a key role. For example, the commodification of food and beauty and exposure to weight stigma, unpleasant eating experiences and general adversity can set the scene. The majority of people with binge-eating disorder do not seek treatment (perhaps related to internalised stigma and shame). Hence opportunities for early intervention and secondary prevention are lost. Most guidelines for binge-eating disorder (based on the limited available research) recommend forms of cognitive psychotherapies and antidepressants. However, novel treatments that target underlying mechanisms are in development. These include interventions to improve emotional regulation and inhibitory control using neuromodulation and/or brain training. New technologies have been applied to talking therapies, including apps which can offer ‘just-in-time interventions’ or virtual reality or avatar work which can deliver more personalised interventions using complex scenarios. Drugs used for the treatment of ADHD, psychiatric and metabolic disorders may have the potential to be repurposed for binge-eating disorder. Thus, this is an area of rapid change with novel solutions being applied to this problem.