Parkinson’s disease (PD) is the fastest-growing neurological condition in the world, affecting 11·8 million people worldwide in 2021. Due to the globally expanding and ageing population, as well as growing industrialisation, this number is likely to increase. Given the absence of disease-modifying pharmacological therapies, this review aimed to examine the effect of dietary interventions on PD progression, motor symptoms, non-motor symptoms, specifically those affecting the gastrointestinal (GI) tract, and severity. To do so, this review synthesised the current evidence from randomised controlled trials (RCTs) on dietary patterns, individual foods and beverages, and nutritional supplements including nutrients, bioactive compounds, and biotics.

Results from the included RCTs failed to demonstrate conclusive evidence for the use of a dietary intervention as a therapy for improving PD progression, symptoms and severity. However, this is likely a reflection of the current scarcity of RCTs in the literature, rather than an outright demonstration of the ineffectiveness of such dietary approaches. In contrast, several trials have demonstrated a beneficial effect of biotic supplementation in managing GI symptoms, particularly constipation syndrome, which may be a promising avenue for improving GI-related issues that affect up to 80 % of PD patients. In conclusion, further RCTs are required to decipher the role that diet may play in mitigating PD progression and severity and improving overall patient care by reducing both motor and non-motor symptoms.

The NOVA food classification system and its categorisation of ultra-processed foods (UPFs) have significantly influenced dietary guidelines worldwide, yet the assumption that all UPFs are uniformly harmful warrants critical examination. Here, a review of evidence revealed substantial heterogeneity in health outcomes across UPF subtypes, with products like sugar-sweetened beverages consistently associated with adverse outcomes while fortified cereals and certain dairy products demonstrate neutral or protective effects. The binary nature of NOVA’s classification fails to account for nutritional composition, fortification benefits, and cultural food traditions, creating inconsistencies in categorisation across different contexts. Methodological limitations in UPF research include inadequate dietary assessment tools, selective reporting of negative findings, and experimental design flaws that conflate processing with other dietary factors. Implementation challenges extend to socioeconomic accessibility, as UPFs often provide cost-effective nutrients for disadvantaged populations and environmental sustainability, where wholesale reduction could increase resource demands. Future directions should develop more nuanced classification systems that integrate processing methods with nutritional quality to better inform public health strategies rather than categorically rejecting all UPFs.

The Nordic Nutrition Recommendations 2023 (NNR2023) serve as the scientific foundation for national dietary guidelines and nutrient recommendations across the Nordic and Baltic countries. We reviewed how NNR2023 was adapted into national food-based dietary guidelines (FBDG) in the Nordic countries and Estonia, focusing specifically on sustainability considerations and policy implications. National FBDG integrated both health and environmental aspects in all countries, except Norway, which addressed environmental aspects only in a separate report. Health impacts served as the primary principle in all countries. Additionally, national policy perspectives, such as domestic food security, were addressed in some countries, while the integration of social and economic sustainability remained very limited. In adopting NNR2023, all countries modelled how implementation would affect nutrient adequacy or health within their food environments, making minor adjustments based on these findings. Guidelines for animal source food groups showed the most variation between countries; Estonia and Denmark established the strictest recommended limits for red meat and total meat, respectively, while Norway was most liberal regarding milk products. Stakeholders participated in the consultation process. The agricultural sector and meat industry primarily maintained pro-meat discourse, which was particularly intense in Norway and Sweden. Transition towards healthy and sustainable diets demands multiple policy instruments – FBDG being just one – alongside a supportive environment and participation from all food system actors.

Personalised nutrition (PN) has emerged as an approach to optimise individual health outcomes through more targeted and tailored dietary recommendations based on unique genetic, phenotypic, medical, lifestyle and contextual factors. The application of artificial intelligence (AI) presents an opportunity to achieve personalised nutrition advice at a scale that has population impact. This review introduces a nutrition audience to different AI applications and offers insights into the concepts of AI that might be relevant to the field of nutrition research. The current and future uses of AI in PN are discussed, as well as the potential benefits and challenges to their application. AI-driven solutions have the potential to improve health and reduce the risk of disease because they can consider more information about an individual in making recommendations. However, challenges such as data interoperability, ethical considerations, and model interpretability remain an issue limiting widespread use at this point. This review will provide a foundational understanding of the application of AI within PN and help to identify opportunities to leverage the potential of AI in transforming dietary guidance and enhancing health outcomes through innovative solutions.

This review highlights the importance of dietary fibres (DF) intake and its interconnection with the gut microbiome and psychological well-being, while also exploring the effects of existing DF interventions on these aspects in adults. The gut microbiota is a complex and diverse ecosystem in which microbial species interact, influencing the human host. DF are heterogeneous, requiring different microbial species to degrade the complex DF structures. Emerging evidence suggests that microbial fermentation of DF produces short-chain fatty acids (SCFA), which may play a role in regulating psychological well-being by affecting neurotransmitter levels, including serotonin. The effectiveness of DF interventions depends on factors such as baseline gut microbiota composition, the dosage and the source of DF consumed. Although the gut microbiota of adults is relatively stable, studies have shown that the abundance of the species in the gut microbiota can change within 24 h of an intervention and may return to baseline following the termination of DF intervention. This review underscores the need for larger and well-powered dietary clinical trials incorporating longitudinal biological sample collections, advanced sequencing and omic techniques (including novel dietary biomarkers and microbial metabolites), validated subjective questionnaires and dietary records. Furthermore, mechanistic studies driven by clinical observations are crucial to understanding gut microbiota function and its underlying biological pathways, informing targeted dietary interventions.

In recognition of the impact of current dietary patterns on human and environmental health, dietary shifts towards sustainable diets are considered crucial to adequately feed a growing global population within planetary boundaries. Whilst the composition of sustainable diets varies to account for regional specificity, consensus exists on the need to reduce meat and increase plant protein intakes in sustainable dietary patterns for high-income settings. Due to the high environmental impact resulting from meat production and observational evidence of higher risks of negatives health outcomes associated with excess red and processed meat, a reduction in meat consumption is considered a ‘win-win’ for both people and the planet. However, meat is an important contributor to dietary protein and micronutrient intakes and plays an important sociocultural role, particularly in the UK and Ireland. Whilst a strong evidence-base exists on the environmental and health benefits associated with increased consumption of whole plant foods such as legumes, nuts and seeds, these foods may not address the barriers associated with lower meat diets. Plant-based meat alternatives (PBMAs) are products created to replicate the taste, texture, appearance and functionality of meat and therefore may provide an acceptable means of facilitating the shift to healthy and more sustainable diets. However, less is known about the health and environmental impact of substituting meat with PBMAs. Therefore, this review summarises the literature on the nutritional, health and environmental impact of PBMAs to better understand the role of these products in healthy and sustainable diets for the UK and Ireland.

My research on dietary protein and the regulation of proteostasis in muscle and the whole body during growth and adult maintenance is reviewed. Growth control involves both permissive and regulatory roles of protein acting with genetic determinants and functional demand, to mediate substrate flow into metabolic consumption, energy storage and growth. In 1995 a Protein-Stat hierarchical model for control of the fat-free mass was proposed and is updated here with special emphasis on the skeletal muscle mass. Control is exerted in large part through a central aminostatic appetite mechanism sensing changes in free amino-acid patterns in response to the balance between their supply in relation to their demand. This acts primarily to maintain skeletal muscle mass at a level set by the linear dimensions of the organism, which in turn is controlled by genetic programming and mediated by the developmental hormones acting together with an appropriate anabolic drive deriving from dietary protein. This, together with other important nutrients like zinc, calcium and vitamin D, provides the regulatory stimulus for growth and protein deposition in all tissues. The applicability of this model to childhood growth and development will be described as well as the maintenance of the adult phenotypic muscle mass within populations with protein intakes varying over a wide range, work which resulted in an adaptive metabolic demand model for protein and amino acid requirements and values for apparent adult protein and lysine requirements. Finally current understanding of aminostatic mechanisms of amino-acid sensing in the brain will be reviewed.

Current food systems pose risks to both population and environmental health. Reducing the intake of animal-based foods, such as dairy products, and increasing consumption of plant-based foods align with priorities for addressing climate change and promoting overall health. Plant-based alternatives to cow’s milk can be readily substituted for cow’s milk without altering meal patterns and food habits, making them a popular choice among those reducing animal-product consumption. However, plant-based milk alternatives do not necessarily provide the same nutrients as cow’s milk, particularly essential micronutrients like iodine. While national data indicate that the UK is iodine-replete, certain population subgroups (such as pregnant women, women of reproductive age, and vegans) remain at risk of iodine deficiency. Young women are more likely than other age groups to consume plant-based milk alternatives, heightening public health concerns about iodine insufficiency in this demographic. Current consumers of plant-based milk alternatives in the UK have lower iodine intake and status compared to consumers of cow’s milk. Population-level effects of replacing milk with plant-based alternatives vary and depend on factors such as the role of plant-based milk alternatives in the diet (i.e. in addition to, or as a replacement for milk), the presence of other iodine sources in the diet, the consumer’s life stage, and whether the alternatives are fortified with iodine. This review examines the literature on plant-based milk alternatives and iodine intake, focusing on implications of this dietary shift and strategies to improve iodine intake in those opting for plant-based milk alternatives in the UK population.

The global nutrition community faces an urgent imperative to address inequities in food security while promoting inclusive approaches to nutrition science and practice. The Nutrition Society of Australia’s 2024 Annual Scientific Meeting on ‘Food for All: Promoting Equity, Diversity, and Inclusion in Nutrition’ addressed this critical challenge through a 4-day programme of cutting-edge, multi-disciplinary research. The conference brought timely focus to key issues, including food access, cultural food practices, nutrition service accessibility, and inclusive research and education approaches. The conference featured public presentations, workshops, oral and poster sessions, symposia, and early career researcher sessions, and emphasised incorporating diverse perspectives while highlighting collaborative approaches to promoting equitable food systems. Coordinated efforts among researchers, healthcare providers, community organisations, industry partners and policymakers remain essential to advance inclusive nutrition practices and ensure equitable access to nutritious food for all populations.

Sustainable diets should promote good health for both the planet and the individual. While there is a clear association between lower environmental impact diets and better health outcomes, intervention studies are needed to determine the range of dietary changes and to understand inter-individual differences in response. Individuals having different responses to dietary interventions are underpinned by a variety of genetic, phenotypic and behavioural factors. The aim of this review is to apply the findings from previous literature examining inter-individual variation and phenotypic response to the future of sustainable healthy diets. Despite changing diets or improving diet quality, physiological responses are varied in randomised controlled trials. To better understand response, individuals can be grouped based on shared baseline characteristics or by their shared response to an intervention. Studies grouping individuals by shared characteristics use a metabolic phenotyping or metabotyping approach which demonstrates that some phenotypes are more predisposed to respond to a particular intervention. Tailoring dietary advice to metabolic phenotype shows promise for improving health and diet quality. However, more evidence is needed to understand the complexity that will come with whole dietary change in the context of sustainable healthy diets. We envisage a future where metabolic phenotyping is an integral element for prescribing personalised nutrition advice for sustainable healthy diets.

Plant-based diets, with limited quantities of animal foods, are increasingly promoted for sustainability and health. In many countries, animal-source foods provide the majority of several micronutrients at a population level; in the UK, milk and dairy products contribute around one third of total calcium, vitamin B12 and iodine intake in adults. Recommendations for a predominantly plant-based diet may have the unintended consequence of reducing intake of micronutrients, particularly in groups with an already-low intake of these nutrients, such as women of reproductive age. Furthermore, young women are the group most likely to replace dairy products with plant-based alternatives. Milk alternatives are often fortified to match the nutrient content of cows’ milk for some micronutrients (e.g. calcium), but not of others (e.g. iodine or vitamin B2). Unfortified alternatives have an iodine concentration that is just 2 % of that of UK cows’ milk, and the rise in popularity of these products may increase iodine-deficiency risk in consumers. Low nutrient intake is of concern prior to, and during, pregnancy, when many of the micronutrients at risk (iron/calcium/iodine) are essential for foetal development. While there may be awareness of some at-risk nutrients on a plant-based diet, this may not be the case for all. At-risk nutrients should be considered in nutrition guidelines and advice given by healthcare professionals to ensure that the diets are well planned and supplemented when necessary. This review focuses on the provision of micronutrients (particularly iodine) from plant-based diets in the UK.

Approximately 60 million individuals worldwide are currently living with dementia. As the median age of the world’s population rises, the number of dementia cases is expected to increase markedly, and to affect ∼150 million individuals by 2050. This will create a huge and unsustainable economic and social burden across the globe. Although promising pharmacological treatment options for Alzheimer’s disease – the most common cause of dementia – are starting to emerge, dementia prevention and risk reduction remain vital. In this review, we present evidence from large-scale epidemiological studies and randomised controlled trials to indicate that adherence to healthy dietary patterns could improve cognitive function and lower dementia risk. We outline potential systemic (e.g. improved cardiometabolic health, lower inflammation, modified gut microbiome composition/metabolism, slower pace of aging) and brain-specific (e.g. lower amyloid-β load, reduced brain atrophy and preserved cerebral microstructure and energetics) mechanisms of action. We also explore current gaps in our knowledge and outline potential directions for future research in this area. Our aim is to provide an update on current state of the knowledge, and to galvanise research on this important topic.

Psoriasis is a chronic debilitating skin disease affecting 2 % of the UK population. The aetiopathogenesis of psoriasis arises from a combination of genetic susceptibly and lifestyle patterns including stress, infections, alcohol misuse, lack of physical activity and adiposity. This unfavourable gene-lifestyle pairing triggers a series of inflammatory responses resulting in the uncontrolled proliferation of skin cells characteristic of psoriasis, which at present is an incurable disease. Concurrent with the systemic nature of the condition, psoriasis has effects beyond the skin with concomitant cardiometabolic complications, arthritis, gastrointestinal diseases and depression, emphasising the need for other strategies beyond pharmaceutical therapies to support psoriasis treatments. The role of diet in psoriasis management has not been clearly established and only two evidence-based recommendations are available for people with psoriasis. This review aims to critically appraise the research examining dietary patterns in psoriasis populations, highlight the gaps in the evidence-base, and present directions for future research.

Nations are revising dietary guidelines to include sustainability recommendations in response to climate change concerns. Given low adherence to current guidelines, consumer inertia is a challenge. A proliferation of nutrition information providers and dietary messages contributes to confusion. All this suggests that health professionals will face considerable obstacles in facilitating a population shift towards sustainable and healthy (SuHe) diets. This review explores the role of nutrition science in shaping dietary behaviour and the challenges of shifting the nutrition narrative to encompass both health and sustainability. Societal transformation towards the ‘asks’ of a SuHe diet will rely on consumer-level transformation of food acquisition, preparation, consumption, storage and disposal behaviours. Acceptance of a higher share of plant-based food and a reduction in animal protein in the diet is likely to provoke disorientations as consumers’ previously unexamined beliefs are challenged. The challenges presented by portion size distortion, protein reduction and replacement, and the role of ultra-processed food are discussed here in terms of sources of confusion. The routes to change involve deeper understanding of responses to disorientations through processes of belief formation and transformation, which are the foundations of subjective knowledge and attitudes, likely mediated through affective factors. In tandem with introducing new potentially disorienting-to-consumers information, health professionals need to consider the environments where this information is presenting and consider how these environments are designed to support action. In doing so, reactance and backlash through belief rejection and behavioural non-adherence could be reduced.

Systems thinking is deeply rooted in history, as far back as Aristotle. However, it has only relatively recently reemerged as an approach to help us understand and intervene in health and food systems. This is particularly salient, given its impact on environmental and population health. Whilst global food is abundant, many people cannot access affordable, healthy and culturally appropriate food. On the other hand, foods of low nutrient density are widely available. Food systems are complex and require complex thinking and approaches that allow us to consider the influence of multiple factors and how the might system respond to change. In turn, this enables the identification of ‘leverage’ points, where policies or interventions are most likely to have a sustained impact. The Foresight obesity map inspired others to adopt systems approaches to help understand the broader social, economic and environmental determinants of obesity to support intervention/policy development. Evaluation of these requires a consideration of complexity to explore why intervention goals may or may not have been successful and how relationships between components or approaches can be enhanced to support implementation and thereby increase the potential for effectiveness. Overall, approaches to understand, intervene, govern and evaluate food systems must themselves be sufficiently complex, or will ultimately be destroyed by the system it seeks to improve. This review paper aims to introduce readers to the application of systems approaches in research within the context of food systems and health, including its traditional/historical origins.