This review explores the evolution of dietary protein intake requirements and recommendations, with a focus on skeletal muscle remodelling to support healthy ageing based on presentations at the 2023 Nutrition Society summer conference. In this review, we describe the role of dietary protein for metabolic health and ageing muscle, explain the origins of protein and amino acid (AA) requirements and discuss current recommendations for dietary protein intake, which currently sits at about 0⋅8 g/kg/d. We also critique existing (e.g. nitrogen balance) and contemporary (e.g. indicator AA oxidation) methods to determine protein/AA intake requirements and suggest that existing methods may underestimate requirements, with more contemporary assessments indicating protein recommendations may need to be increased to >1⋅0 g/kg/d. One example of evolution in dietary protein guidance is the transition from protein requirements to recommendations. Hence, we discuss the refinement of protein/AA requirements for skeletal muscle maintenance with advanced age beyond simply the dose (e.g. source, type, quality, timing, pattern, nutrient co-ingestion) and explore the efficacy and sustainability of alternative protein sources beyond animal-based proteins to facilitate skeletal muscle remodelling in older age. We conclude that, whilst a growing body of research has demonstrated that animal-free protein sources can effectively stimulate and support muscle remodelling in a manner that is comparable to animal-based proteins, food systems need to sustainably provide a diversity of both plant and animal source foods, not least for their protein content but other vital nutrients. Finally, we propose some priority research directions for the field of protein nutrition and healthy ageing.

Poor dietary patterns leading to poorer health and increased health care use have affected people living in disadvantaged economic circumstances in the UK for decades, which many fear will be exacerbated due to the UK's current so-called ‘cost of living crisis’. The voices of experts by experience of those health and social inequalities are not routinely included in health improvement intervention development in relation to obesity prevention policy and programmes. Obesity is highly correlated with food insecurity experience in high-income country contexts (where food insecurity data are routinely collected) and is similarly socially patterned. Using a health equity lens, this review paper highlights qualitative research findings that have revealed the perspectives and direct experiences of people living with food insecurity, or those others supporting food-insecure households, that shed light on the role and influence of the socio-economic contextual factors food-insecure people live with day-to-day. Insights from qualitative research that have focused on the granular detail of day-to-day household resource management can help us understand not only how food insecurity differentially impacts individual household members, but also how behavioural responses/food coping strategies are playing into pathways that lead to avoidable ill health such as obesity, diabetes and other chronic health conditions, including mental health problems. This review paper concludes by discussing research and policy implications in relation to food-insecure households containing people with chronic health conditions, and for pregnant women and families with infants and very young children living in the UK today.

The present paper provides an overview of the approach to developing food-based dietary recommendations in the UK. UK dietary recommendations are based on independent advice from the Scientific Advisory Committee on Nutrition (SACN). SACN's remit includes specific reference to the nutrient content of individual foods and advice on diet as a whole, including the definition of a balanced diet. SACN's approach is set out in its Framework for Evaluating Evidence and its assessments are supported by the data provided by the National Diet and Nutrition Survey. SACN's risk assessments have primarily focused on energy requirements, macro and micronutrients and/or the needs of specific population groups. However, dietary patterns or individual foods and health outcomes have been considered where sufficient evidence is available. An example of this is SACN's risk assessment on carbohydrates and health, which included consideration of evidence on sugar-sweetened beverages and the resulting dietary recommendations on free sugars and sugar-sweetened beverages led to a range of policies to reduce sugar intake in the UK, including the soft drinks industry levy. SACN has also recently published a position statement on processed foods and health. Government dietary advice is encapsulated in the UK's national food model, the Eatwell Guide. The Eatwell Guide shows the proportions in which different food groups should be consumed to have a well-balanced, healthier, more sustainable diet, to help meet nutrient requirements and reduce the risk of chronic disease. Any substantive change to government dietary advice is likely to lead to a review of the national food model.

Food insecurity – when individuals or households have difficulty accessing sufficient, safe, culturally appropriate and nutritious food due to lack of money or other resources – is a global public health concern. Levels of food insecurity have increased across the UK in recent years, due in part to a decade of austerity, widespread loss of income during the COVID-19 pandemic and the more recent cost-of-living crisis, leading to rising use of food banks. The stress of living with uncertain access to food and going periods without food is damaging to physical and mental health. Food insecurity is linked to both obesity and malnutrition, as often the most readily available foods are processed, high in fats, sugars and salt, but low in essential nutrients for health. While recognising that many of the drivers of food insecurity, and health inequalities more broadly (i.e. the social determinants of health) lie outside the health service, it is increasingly acknowledged that the National Health Service – and primary care in particular – has a key role to play in mitigating health inequalities. This review considers the potential role of healthcare in mitigating food insecurity, with a focus on primary care settings. Recent initiatives in Scotland, such as community links workers and general practitioner practice-attached financial advice workers, have shown promise as part of a more community-oriented approach to primary care, which can mitigate the effects of food insecurity. However, a more ‘upstream’ response is required, including ‘cash first’ interventions as part of broader national strategies to end the need for food banks.

This review presents evidence related to the postprandial responses after consumption of dairy products focusing on the effect of the dairy matrix and lipid response, which was also presented as part of a speech at the Nutrition Society Winter Conference, January 2023. The key findings are that the dairy product(s) that differentiate from others in the postprandial TAG response are products with a semi-solid structure. There were no differences in lipid responses between cheese and butter. The main factors viscosity, fat globule size and milk fat globule membrane do not seem to explain the effect of the dairy matrix in the acute postprandial response. In summary, it is very difficult to investigate the effects of the dairy matrix per see and with the few studies conducted to date, no clear cause and effect can be established. Future research should focus on the semi-solid dairy matrix, and studies investigating specifically the yoghurt matrix are warranted.

The high levels of non-communicable diseases such as CVD and type 2 diabetes mellitus are linked to obesity and poor diet. This continuing emphasis on health in relation to food is proving a powerful driver for the development of cheap but palatable and more functional foods. However, the efficacy of such foods is often hard to prove in human subjects. Thus, a suite of tools has been developed including in silico and in vitro simulations and animal models. Although animal models offer physiologically relevant platforms for research, their use for experimentation is problematic for consumers. Thus, in vitro methods such as Infogest protocols have been developed to provide digestion endpoints or even an indication of the kinetics of digestion. These protocols have been validated for a range of food systems but they still miss the final absorption step. This review discusses the use of such in vitro models and what further steps need to be included to make the bioaccessibility determination more relevant to bioavailability and human health.

Diets and dietary constituents that we consume have a considerable impact on disease risk. Intriguingly these effects may be modulated to some extent by sex. Lack of female representation in nutritional studies as well as a lack of stratification by sex has and continues to limit our understanding of these sex × diet interactions. Here we provide an overview of the current and available literature describing how exposure to certain dietary patterns (Western-style diet, Mediterranean diet, vegetarian/vegan, ketogenic diet) and dietary constituents (dietary fibre, PUFA and plant bioactive) influences disease risk in a sex-specific manner. Interestingly, these sex differences appear to be highly disease-specific. The identification of such sex differences in response to diet stresses the importance of sex stratification in nutritional research.

Consumption of snacks and ultra-processed foods (UPF) high in fat, salt and sugar (HFSS) is associated with rising rates of obesity and growing socioeconomic disparities in nutrition. While infancy, childhood and adolescence are critical periods for development of dietary preferences, there remains a dearth of research exploring factors that underpin snacking behaviour over this time. This review aims to address this gap by drawing from qualitative lived experience research, with 122 families of different socioeconomic position (SEP), to explore how the (i) home food environment, (ii) food environment and (iii) social value and meanings of food shape parental provision of snacks. This review shows that snacking holds important meanings in everyday family life, with infants integrated into existing snacking practices from an early age. Price promotions, low-cost and long shelf-lives all make UPF and HFSS snacks an appealing option for many low-SEP parents; while children's requests and preferences for HFSS snacks present a challenge across SEP. However, higher-SEP parents can ensure fresh fruits are always available as an alternative snack, while fruit is described as a financially risky expenditure for low-SEP families. The present findings also indicate that retailers and producers are increasingly promoting ‘healthier’ snacks through product packaging and marketing, such as ‘meets one of your five a day’, despite these products displaying similar nutritional profiles to traditional UPF and HFSS snacks. We outline a series of policy recommendations, including extending Healthy Start Vouchers and the Fruit and Vegetable Scheme in schools and action to address misleading product marketing and packaging.

Diminished skeletal muscle strength and size, termed sarcopenia, contributes substantially to physical disability, falls, dependence and reduced quality of life among older people. Physical activity and nutrition are the cornerstones of sarcopenia prevention and treatment. The optimal daily protein intake required to preserve muscle mass and function among older adults is a topic of intense scientific debate. Older adults require protein intakes about 67 % higher than their younger counterparts to maximally stimulate postprandial muscle protein synthesis rates. In addition, evidence suggests a possible benefit of increasing protein intake above the population reference intake (0⋅83 g/kg/d) on lean mass and, when combined with exercise training, muscle strength. In addition to protein quantity, protein quality, the pattern of protein intake over the day and specific amino acids (i.e. leucine) represent key considerations. Long-chain n-3 PUFA (LC n-3 PUFA) supplementation has been shown to enhance muscle protein synthesis rates, increase muscle mass and function and augment adaptations to resistance training in older adults. Yet, these effects are not consistent across all studies. Emerging evidence indicates that an older person's dietary, phenotypic and behavioural characteristics may modulate the efficacy of protein and LC n-3 PUFA interventions for promoting improvements in muscle mass and function, highlighting the potential inadequacy of a ‘one-size-fits-all’ approach. The application of personalised or precision nutrition to sarcopenia represents an exciting and highly novel field of research with the potential to help resolve inconsistencies in the literature and improve the efficacy of dietary interventions for sarcopenia.

A diet low in fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) improves functional bowel symptoms and is a second-line dietary management strategy for the treatment of irritable bowel syndrome (IBS). The diet is complex and involves three stages: restriction, reintroduction and personalisation and clinical effectiveness is achieved with dietitian-led education; however, this is not always available. The aim of this review is to provide an update on the evidence for using the low FODMAP diet, with a focus on the impact of FODMAP restriction and reintroduction considering long-term management of IBS in a clinical setting. Randomised controlled trials have assessed symptom response, quality of life, dietary intake and changes to the gut microbiota during FODMAP restriction. Systematic reviews and meta-analyses consistently report that FODMAP restriction has a better symptom response compared with control diets and a network analysis reports the low FODMAP diet is superior to other dietary treatments for IBS. Research focused on FODMAP reintroduction and personalisation is limited and of lower quality, however common dietary triggers include wheat, onion, garlic, pulses and milk. Dietitian-led delivery of the low FODMAP diet is not always available and alternative education delivery methods, e.g. webinars, apps and leaflets, are available but remove the personalised approach and may be less acceptable to patients and may introduce safety concerns in terms of nutritional adequacy. Predicting response to the low FODMAP diet using symptom severity or a biomarker is of great interest. More evidence on less restrictive approaches and non-dietitian-led education delivery methods are needed.

Indigenous peoples and ethnic minority groups often experience poor diet quality and poor health outcomes. Such inequities may be partially due to nutrition interventions not meeting the unique cultural and linguistic needs of these population groups, which could be achieved using co-creation and/or personalised approaches. Cultural adaptation or tailoring of nutrition interventions has shown promise in improving some aspects of dietary intake, but this requires careful consideration to ensure it does not inadvertently exacerbate dietary inequities. The aim of this narrative review was to examine examples of cultural adaptations and/or tailoring of public health nutrition interventions that improved the dietary intake and to consider implications for the optimal design and implementation of personalised and precision nutrition interventions. This review identified six examples of cultural adaptation and/or tailoring of public health nutrition intervention in Indigenous peoples and ethnic minority groups across Australia, Canada and the US. All studies used deep socio-cultural adaptations, such as the use of Indigenous storytelling, and many included surface-level adaptations, such as the use of culturally appropriate imagery in intervention materials. However, it was not possible to attribute any improvements in dietary intake to cultural adaptation and/or tailoring per se, and the minimal reporting on the nature of adaptations limited our ability to determine whether the interventions used true co-creation to design content or were adapted from existing interventions. Findings from this review outline opportunities for personalised nutrition interventions to use co-creation practices to design, deliver and implement interventions in collaboration with Indigenous and ethnic minority groups.

Food-based dietary guidelines have been the basis of public health recommendations for over half a century, but more recently, there has been a trend to classify the health properties of food not by its nutrient composition, but by the degree to which it has been processed. This concept has been supported by many association studies, narrative reviews and the findings from one randomised controlled feeding trial, which demonstrated the sustained effect of ultra-processed diets on increasing both energy intake and body weight. This has led to widespread speculation as to specific features of ultra-processed foods that promote increased energy intakes. Rising interest in the ultra-processed topic has led to proposals to include guidance and restrictions on the consumption of processed foods in national dietary guidelines, with some countries encouraging consumers to avoid highly processed foods completely, and only choose minimally processed foods. However, there remains a lack of consensus on the role of processed foods in human health when faced with the challenges of securing the food supply for a growing global population, that is, healthy, affordable and sustainable. There has also been criticism of the subjective nature of definitions used to differentiate foods by their degree of processing, and there is currently a lack of empirical data to support a clear mechanism by which highly processed foods promote greater energy intakes. Recommendations to avoid all highly processed foods are potentially harmful if they remove affordable sources of nutrients and will be impractical for most when an estimated two-thirds of current energy purchased are from processed or ultra-processed foods. The current review highlights some considerations when interpreting the dietary association studies that link processed food intake to health and offers a critique on some of the mechanisms proposed to explain the link between ultra-processed food and poor health. Recent research suggests a combination of higher energy density and faster meal eating rates are likely to influence meal size and energy intakes from processed foods and offers new perspectives on how to manage this in the future. In going beyond the ultra-processed debate, the aim is to summarise some important considerations when interpreting existing data and identify the important gaps for future research on the role of processed food in health.

As interest in Australian native products continues to grow worldwide, Aboriginal and Torres Strait Islander peoples (First Peoples) are striving to be industry leaders in the production of their traditional foods that are being developed for commercial markets. To successfully gain market approval both within Australia and globally, food regulatory authorities require at least a documented history of safe use to indicate dietary safety. Moreover, many countries also require compositional analysis and safety data to further support their safe human consumption. However, safety data are lacking for many of these traditional food items and the history that surrounds their safe use has rarely been recorded in written form, but rather passed on through cultural practices and language. This review evaluates the suitability of current frameworks for assessing the dietary safety of traditional foods and highlights the food-safety regulatory hurdles currently felt by First Peoples and their businesses attempting to enter the Australian native foods industry. These issues also extend to the requirements of food regulatory authorities around the world, when assessing the market eligibility of traditional food items. Potential solutions to these problems are discussed, including new proposed processes that can be incorporated into the current food regulatory frameworks. Importantly, these proposed processes would allow the dietary risk assessment of traditional foods to be completed in a manner that better accommodates the stories, traditional knowledge and interests of First Peoples, while also meeting the safety data requirements set out by regulatory bodies both within Australia and around the world.

Three-dimensional (3D) food printing is a rapidly emerging technology offering unprecedented potential for customised food design and personalised nutrition. Here, we evaluate the technological advances in extrusion-based 3D food printing and its possibilities to promote healthy and sustainable eating. We consider the challenges in implementing the technology in real-world applications. We propose viable applications for 3D food printing in health care, health promotion and food waste upcycling. Finally, we outline future work on 3D food printing in food safety, acceptability and economics, ethics and regulations.

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.

Modifiable lifestyle factors, such as improved nutrition, are crucial in maintaining cognitive health in older age. Fruit and vegetables represent healthy and sustainable sources of nutrients with the potential to prevent age-related cognitive decline. The aim of this review is to synthesise the available evidence, from epidemiological and randomised controlled trials (RCT), regarding the role of fruit and vegetables in sustaining healthy cognitive function. Epidemiological studies of combined fruit and vegetable intake suggest that increased consumption may sustain cognition in later life. The evidence appears to be stronger for an association between vegetables and cognition, particularly for green leafy and cruciferous vegetables. Specific benefits shown for berries, citrus fruits, avocado and nuts suggest fruit is worthy of further investigation in relation to cognition. Data from RCT indicate benefits to differing aspects of cognition following citrus and berry fruits, cocoa and peanuts, but the data are limited and there are a lack of studies exploring effects of vegetables. There is growing evidence for an association between fruit and vegetable intake and cognitive function, but this is not always consistent and the data from RCT are limited. Issues in previous research are highlighted, such as strict exclusion criteria, absence of baseline nutritional status data and lack of consideration of individual differences, which may explain the weaker findings from RCT. Inclusion of those most at risk for cognitive decline is recommended in future nutrition and cognition research.

The recent Covid-19 pandemic highlighted stark social inequalities, notably around access to food, nutrition and to green or blue space (i.e. outdoor spaces with vegetation and water). Consequently, obesity is socio-economically patterned by this inequality; and while the environmental drivers of obesity are widely acknowledged, there is currently little upstream intervention. We know that living with obesity contributes to increasing health inequalities, and places healthcare systems under huge strain. Our environment could broadly be described obesogenic, in the sense of supporting unhealthful eating patterns and sedentary behaviour. Evidence points to the existence of nearly 700 UK obesity policies, all of which have had little success. Obesity prevention and treatment has focused on educational and behavioural interventions targeted at individual consumers. A more sustainable approach would be to try and change the environments that promote less healthy eating and high energy intake as well as sedentary behaviour. Approaches which modify the environment have the potential to assist in the prevention of this complex condition. This review paper focuses on the role of wider food environments or foodscapes. While there is an imperfect evidence base relating to the role of the foodscape in terms of the obesity crisis, policy, practice, civic society and industry must work together and take action now, in areas where current evidence suggests change is required. Despite the current cost-of-living crisis, shaping the foodscape to better support healthful eating decisions has the potential to be a key aspect of a successful obesity prevention intervention.

The precision nutrition paradigm is based on the premise that substantial variation exists between human subjects in terms of diet-related disease risk and response to dietary interventions. In terms of better defining, ‘the right diet for the right person at the right time’ may be more appropriate than ‘one-diet-fits-all’. This review will explore how systems biology and nutrigenomics approaches have advanced the precision nutrition paradigm. We will draw upon a number of elegant mechanistic studies that have enhanced our understanding with respect to the complex biology and inter-organ crosstalk, relating to inflammation and metabolism, that underpin cardio-metabolic health. Also, this review will explore the extent to which more targeted, precision nutrition approaches may attenuate adverse risk factors associated with cardio-metabolic disease. We will focus on the key characteristics or ‘metabotypes’ of high- v. low-risk individuals and response v. non-response to interventions, to generate greater insights with respect to risk stratification and therapeutic interventions to enhance disease prevention. The goal is to utilise systems biology to enhance understanding by underpinning more targeted nutritional approaches, which may improve efficacy of personalised nutrition interventions.