There are many health and nutrition implications of suffering from multimorbidity, which is a huge challenge facing health and social services. This review focuses on malnutrition, one of the nutritional consequences of multimorbidity. Malnutrition can result from the impact of chronic conditions and their management (polypharmacy) on appetite and nutritional intake, leading to an inability to meet nutritional requirements from food. Malnutrition (undernutrition) is prevalent in primary care and costly, the main cause being disease, accentuated by multiple morbidities. Most of the costs arise from the deleterious effects of malnutrition on individual’s function, clinical outcome and recovery leading to a substantially greater burden on treatment and health care resources, costing at least £19·6 billion in England. Routine identification of malnutrition with screening should be part of the management of multimorbidity together with practical, effective ways of treating malnutrition that overcome anorexia where relevant. Nutritional interventions that improve nutritional intake have been shown to significantly reduce mortality in individuals with multimorbidities. In addition to food-based interventions, a more ‘medicalised’ dietary approach using liquid oral nutritional supplements (ONS) can be effective. ONS typically have little impact on appetite, effectively improve energy, protein and micronutrient intakes and may significantly improve functional measures. Reduced treatment burden can result from effective nutritional intervention with improved clinical outcomes (fewer infections, wounds), reducing health care use and costs. With the right investment in nutrition and dietetic resources, appropriate nutritional management plans can be put in place to optimally support the multimorbid patient benefitting the individual and the wider society.

Multimorbidity, the existence of two or more concurrent chronic conditions in a single individual, represents a major global health challenge. The Nutrition Society’s 2023 Winter Conference at the Royal Society, London focused on the topic of ‘Diet and lifestyle strategies for prevention and management of multimorbidity’, with symposia designed to explore pathways for prevention of multimorbidity across the lifecourse, the role of ageing, the gut-brain-heart connection and lifestyle strategies for prevention and management of multimorbidity. It also considered machine learning and precision nutrition approaches for addressing research challenges in multimorbidity. The opening plenary lecture discussed advancing diet and lifestyle research to address the increasing burden and complexity of multimorbidity. The two-day programme concluded with a plenary which addressed the key dietary risk factors and policies in multimorbidity prevention.

Oral health is a critical component of overall health and well-being, not just the absence of disease. The objective of this review paper is to describe relationships among diet, nutrition and oral and systemic diseases that contribute to multimorbidity. Diet- and nutrient-related risk factors for oral diseases include high intakes of free sugars, low intakes of fruits and vegetables and nutrient-poor diets which are similar to diet- and nutrient-related risk factors for systemic diseases. Oral diseases are chronic diseases. Once the disease process is initiated, it persists throughout the lifespan. Pain and tissue loss from oral disease leads to oral dysfunction which contributes to impaired biting, chewing, oral motility and swallowing. Oral dysfunction makes it difficult to eat nutrient-dense whole grains, fruits and vegetables associated with a healthy diet. Early childhood caries (ECC) associated with frequent intake of free sugars is one of the first manifestations of oral disease. The presence of ECC is our ‘canary in the coal mine’ for diet-related chronic diseases. The dietary sugars causing ECC are not complementary to an Eatwell Guide compliant diet, but rather consistent with a diet high in energy-dense, nutrient-poor foods – typically ultra-processed in nature. This diet generally deteriorates throughout childhood, adolescence and adulthood increasing the risk of diet-related chronic diseases. Recognition of ECC is an opportunity to intervene and disrupt the pathway to multimorbidities. Disruption of this pathway will reduce the risk of multimorbidities and enable individuals to fully engage in society throughout the lifespan.

Globally, we are currently facing a rapid demographic shift leading to an increase in the proportion of older adults within the population. This raises concerns about the potential increase in age-related diseases and their impact on our ability to provide adequate health and end-of-life care. To apply appropriate interventions, understanding the changes that happen with ageing becomes essential. Ageing is often accompanied by a decrease in appetite and physical activity, which may lead to malnutrition, resulting in decreased muscle mass, physical capabilities and independence. To preserve muscle mass, older adults are advised to increase protein intake and physical activity. However, protein’s high satiating effect may cause reduced energy intake. Physical activity is also advised to maintain or enhance older adult’s appetite. This review paper aims to discuss appetite-related changes that occur with ageing and their consequences. In particular, it will focus on investigating the relationship between protein intake and physical activity and their impact on appetite and energy intake in the ageing population. Recent studies suggest that physical activity might contribute to maintaining or enhancing appetite in older adults. Nevertheless, establishing a definitive consensus on the satiating effect of protein in ageing remains a work in progress, despite some promising results in the existing literature.

The aim of this review is to provide an overview of the history in support of the role of dietary saturated fatty acids (SFA) in the development of cardiovascular disease (CVD), and the controversy and consensus for the evidence in support of guidelines to remove and replace SFA with unsaturated fatty acids. The review will also examine the existence, origins, and implications for CVD risk of variability in serum LDL-cholesterol in response to these guidelines. While the quality of supporting evidence for the efficacy of restricting SFA on CVD risk has attracted controversy, this has helped to increase understanding of the inter-relationships between SFA, LDL-cholesterol and CVD, and reinforce confidence in this dietary recommendation. Nevertheless, there is significant inter-individual variation in serum LDL-C in response to this dietary change. The origins of this variation are multi-factorial and involve both dietary and metabolic traits. If serum biomarkers of more complex metabolic traits underlying LDL-responsiveness can be identified, this would have major implications for the targeting of these dietary guidelines to LDL-responders, to maximise the benefit to their cardiovascular health.

Excess body weight is associated with increased mortality and risk of developing CVD. Body fat distribution is now considered a better indicator of disease risk than BMI, with central adiposity associated with dyslipidaemia and insulin resistance. Dietary modification is unquestionably important in the prevention of obesity and CVD, with the type but not the amount of dietary fat emerging as an important determinant of both diseases. Although reducing SFA intake via replacement with unsaturated fatty acids (UFA) is a key public health strategy for CVD prevention, variability in the lipid lowering response has been observed. This narrative review aims to investigate the link between adiposity and CVD risk, and the role of dietary fat composition and APOLIPOPROTEIN (APO)E genotype on this relationship. In the absence of weight loss, replacing dietary SFA with UFA reduces central adiposity and anthropometric measures, and is linked with lower total and LDL-cholesterol concentrations. However, differences in study populations and body composition techniques need to be taken into consideration. To date, only a limited number of studies have determined the role of APOE on body composition and CVD risk, but findings are inconsistent. Both APOE2 and APOE4 alleles have been correlated with adiposity related markers, and an APOE genotype–BMI interaction has been reported on fasting lipids. However, studies are often performed retrospectively leading to small sample sizes within the genotype groups. Further studies are needed to confirm the relationship between APOE genotype, adiposity and circulating CVD risk markers.

Nutritional requirements of individuals vary across the lifecycle, according to activity, age and gender. To optimize human health, consideration of nutritional priorities at each stage is needed. This conference brought together multidisciplinary experts in maternal and child nutrition and health, cardiometabolic and plant-based nutrition and dietitians involved in the care of vulnerable populations, plus nutritional metabolism, health and ageing. The presentations highlighted the most important nutrition research in these areas, updating knowledge and suggesting how dietary advice and policy could be adapted to incorporate research findings. With the global increase in non-communicable disease (NCD) and nutrition being considered as a key modifiable risk factor for the prevention and management of NCD, this conference was much needed.

The dual burden of malnutrition is characterised by the coexistence of undernutrition alongside overweight/obesity and diet-related noncommunicable diseases. It is a paradox which disproportionately affects women and is applicable to those who become pregnant after weight loss surgery. Obesity before and during pregnancy is associated with increased risk of adverse perinatal outcomes in both mother and child. Overall lifestyle interventions targeting weight loss in the preconception period have not proven effective, with people, and women in particular, increasingly seeking weight loss surgery. In women with severe obesity, surgery may normalise hormonal abnormalities and improve fertility. In those who become pregnant after surgery, evidence suggests a better overall obstetric outcome compared to those with severe obesity managed conservatively; however, there is heightened risk of maternal nutritional deficiencies and infants born small for gestational age. Specifically, pregnancy soon after surgery, in the catabolic phase when rapid weight loss is occurring, has the potential for poor outcomes. Lifelong micronutrient supplementation is required, and there is considerable risk of malnutrition if nutritional aftercare guidelines are not adhered to. It is therefore recommended that pregnancy is delayed until a stable weight is achieved and is supported by individualised advice from a multidisciplinary team. Further research is required to better understand how weight loss surgery affects the chances of having a healthy pregnancy and to ultimately improve nutritional management and patient care. In this review, we aim to summarise the evidence and guidance around nutrition during pregnancy after weight loss surgery.

This review aims to emphasise the impact of poor nutrition on children’s health and psychological well-being, urging those involved in childhood obesity or nutrition services to broaden their intervention approach. Poor nutrition and childhood obesity affect physical and psychological health. The stress of living with obesity further impacts quality of life, well-being and self-esteem. Children living with obesity may experience adverse childhood events and stress, and young people are able to recall the impact of psychosocial issues such as experiencing stigma and discrimination. Food is often a coping mechanism for managing negative emotions, perpetuating cycles of emotional coping and unhealthy eating behaviours. UK guidelines recommend family-based, multi-component weight management interventions for children living with obesity. Interventions mainly target health behaviours and utilise behaviour change techniques attempting to directly improve diet and physical activity as behavioural outcomes. Whilst these interventions may show some improvements in psychological well-being, there is limited consideration or understanding of the underlying mechanisms of action which indirectly influence engagement and the sustainability of the behaviour change. Lack of attention and inclusion of psychosocial variables in intervention implementation may help explain the variable effectiveness reported across childhood obesity interventions. In conclusion, enhancing the effectiveness of childhood obesity interventions requires a broader approach that fully incorporates psychosocial factors. Those responsible for commissioning, designing and implementing these interventions should adopt a holistic approach that addresses psychological and emotional needs while incorporating underlying mechanisms of action. This shift in focus could result in more sustainable and comprehensive treatment for childhood obesity.

In the UK, populations of Black African and Caribbean (BAC) ethnicity suffer higher rates of cardiometabolic disease than White Europeans (WE). Obesity, leading to increased visceral adipose tissue (VAT) and intrahepatic lipid (IHL), has long been associated with cardiometabolic risk, driving insulin resistance and defective fatty acid/lipoprotein metabolism. These defects are compounded by a state of chronic low-grade inflammation, driven by dysfunctional adipose tissue. Emerging evidence has highlighted associations between central complement system components and adipose tissue, fatty acid metabolism and inflammation; it may therefore sit at the intersection of various cardiometabolic disease risk factors. However, increasing evidence suggests an ethnic divergence in pathophysiology, whereby current theories fail to explain the high rates of cardiometabolic disease in BAC populations. Lower fasting and postprandial TAG has been reported in BAC, alongside lower VAT and IHL deposition, which are paradoxical to the high rates of cardiometabolic disease exhibited by this ethnic group. Furthermore, BAC have been shown to exhibit a more anti-inflammatory profile, with lower TNF-α and greater IL-10. In contrast, recent evidence has revealed greater complement activation in BAC compared to WE, suggesting its dysregulation may play a greater role in the high rates of cardiometabolic disease experienced by this population. This review outlines the current theories of how obesity is proposed to drive cardiometabolic disease, before discussing evidence for ethnic differences in disease pathophysiology between BAC and WE populations.

Maintaining a healthy weight during pregnancy is critical for both women's and children's health. Excessive gestational weight gain (GWG) can lead to complications such as gestational diabetes, hypertension and caesarean delivery. Insufficient GWG can cause fetal growth restriction and increase infant mortality risk. Additionally, postpartum weight retention raises risk of obesity, type 2 diabetes and other chronic diseases for both mother and child. This review seeks to identify current obstacles in weight management research during and after pregnancy and explore evidence-based strategies to overcome them. Pregnancy offers a window of opportunity for health behaviour changes as women are more receptive to education and have regular contact with health services. Staying within Institute of Medicine's recommended GWG ranges is associated with better maternal and fetal outcomes. Systematic review evidence supports structured diet and physical activity pregnancy interventions, leading to reduced GWG and fewer complications. Health economic evaluation indicates significant returns from implementation, surpassing investment costs due to decreased perinatal morbidity and adverse events. However, the most effective way to implement interventions within routine antenatal care remains unclear. Challenges increase in the postpartum period due to competing demands on women physically, mentally and socially, hindering intervention reach and retention. Flexible, technology-supported interventions are needed, requiring frameworks such as penetration-implementation-participation-effectiveness and template-for-intervention-description-and-replication for successful implementation. Greater research efforts are necessary to inform practice and investigate fidelity aspects through pragmatic implementation trials during the pregnancy and postpartum periods. Understanding the best ways to deliver interventions will empower women to maintain a healthy weight during their reproductive years.

The aim of this review is to provide an overview of dietary interventions delivered during pregnancy for the prevention of gestational diabetes mellitus (GDM). GDM increases the risk of adverse pregnancy and neonatal outcomes, and also increases future cardiometabolic risks for both the mother and the offspring. Carrying or gaining excessive weight during pregnancy increases the risk of developing GDM, and several clinical trials in women with overweight or obesity have tested whether interventions aimed at limiting gestational weight gain (GWG) could help prevent GDM. Most dietary interventions have provided general healthy eating guidelines, while some had a specific focus, such as low glycaemic index, increased fibre intake, reducing saturated fat or a Mediterranean-style diet. Although trials have generally been successful in attenuating GWG, the majority have been unable to reduce GDM risk, which suggests that limiting GWG may not be sufficient in itself to prevent GDM. The trials which have shown effectiveness in GDM prevention have included intensive face-to-face dietetic support, and/or provision of key foods to participants, but it is unclear whether these strategies could be delivered in routine practice. The mechanism behind the effectiveness of some interventions over others remains unclear. Dietary modifications from early stages of pregnancy seem to be key, but the optimum dietary composition is unknown. Future research should focus on designing acceptable and scalable dietary interventions to be tested early in pregnancy in women at risk of GDM.

Sufficient sleep is necessary for optimal health, daytime performance and wellbeing and the amount required is age-dependent and decreases across the lifespan. Sleep duration is usually affected by age and several different cultural, social, psychological, behavioural, pathophysiological and environmental factors. This review considers how much sleep children and adults need, why this is important, what the consequences are of insufficient sleep and how we can improve sleep. A lack of the recommended amount of sleep for a given age group has been shown to be associated with detrimental effects on health including effects on metabolism, endocrine function, immune function and haemostatic pathways. Obesity has increased worldwide in the last few decades and the WHO has now declared it a global epidemic. A lack of sleep is associated with an increased risk of obesity in children and adults, which may lead to future poor health outcomes. Data from studies in both children and adults suggest that the relationship between sleep and obesity may be mediated by several different mechanisms including alterations in appetite and satiety, sleep timing, circadian rhythm and energy balance. Moreover, there is evidence to suggest that improvements in sleep, in both children and adults, can be beneficial for weight management and diet and certain foods might be important to promote sleep. In conclusion this review demonstrates that there is a wide body of evidence to suggest that sleep and obesity are causally related and recommends that further research is required to inform policy, and societal change.

This review aims to critically evaluate the efficacy of long-chain ո-3 PUFA ingestion in modulating muscle protein synthesis (MPS), with application to maintaining skeletal muscle mass, strength and function into later life. Ageing is associated with a gradual decline in muscle mass, specifically atrophy of type II fibres, that is exacerbated by periods of (in)voluntary muscle disuse. At the metabolic level, in otherwise healthy older adults, muscle atrophy is underpinned by anabolic resistance which describes the impaired MPS response to non-pharmacological anabolic stimuli, namely, physical activity/exercise and amino acid provision. Accumulating evidence implicates a mechanistic role for n-3 PUFA in upregulating MPS under stimulated conditions (post-prandial state or following exercise) via incorporation of EPA and DHA into the skeletal muscle phospholipid membrane. In some instances, these changes in MPS with chronic ո-3 PUFA ingestion have translated into clinically relevant improvements in muscle mass, strength and function; an observation evidently more prevalent in healthy older women than men. This apparent sexual dimorphism in the adaptive response of skeletal muscle metabolism to EPA and DHA ingestion may be related to a greater propensity for females to incorporate ո-3 PUFA into human tissue and/or the larger dose of ingested ո-3 PUFA when expressed relative to body mass or lean body mass. Future experimental studies are warranted to characterise the optimal dosing and duration of ո-3 PUFA ingestion to prescribe tailored recommendations regarding n-3 PUFA nutrition for healthy musculoskeletal ageing into later life.

This review will provide an overview of the immune system and then describe the effects of frailty, obesity, specific micronutrients and the gut microbiota on immunity and susceptibility to infection including data from the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic where relevant. A key role for the immune system is providing host defence against pathogens. Impaired immunity predisposes to infections and to more severe infections and weakens the response to vaccination. A range of nutrients, including many micronutrients, play important roles in supporting the immune system to function. The immune system can decline in later life and this is exaggerated by frailty. The immune system is also weakened with obesity, generalised undernutrition and micronutrient deficiencies, which all result in increased susceptibility to infection. Findings obtained during the SARS-CoV-2 pandemic support what was already known about the effects of ageing, frailty and obesity on immunity and susceptibility to infection. Observational studies conducted during the pandemic also support previous findings that multiple micronutrients including vitamins C, D and E, zinc and selenium and long-chain n-3 fatty acids are important for immune health, but whether these nutrients can be used to treat those already with coronavirus disease discovered in 2019 (COVID-19), particularly if already hospitalised, is uncertain from current inconsistent or scant evidence. There is gut dysbiosis in patients with COVID-19 and studies with probiotics report clinical improvements in such patients. There is an inverse association between adherence to a healthy diet and risk of SARS-CoV-2 infection and hospitalisation with COVID-19 which is consistent with the effects of individual nutrients and other dietary components. Addressing frailty, obesity and micronutrient insufficiency will be important to reduce the burden of future pandemics and nutritional considerations need to be a central part of the approach to preventing infections, optimising vaccine responses and promoting recovery from infection.

Plant-based substitutes (PBS) are seen as a convenient way to transition to a more plant-based diet, but their potential health benefits and nutritional concerns remain debated. Based on a review of the literature, it is concluded here that the primary risk of insufficient nutrient intake with PBS concerns iron and calcium, which are critical to the nutritional value of PBS. Other risks were identified but these would depend on the characteristics of the overall diet, as is the case for iodine in a diet containing no seafood or dairy, and vitamin B12 in a vegetarian/vegan diet. Conversely, the use of PBS is also expected to confer some benefits for long-term health because it would result in higher fibre intakes (in the case of meat PBS) and lower SFA intakes (but higher PUFA/MUFA intakes), but attention should be paid to a potential increase in sodium intake with PBS of meat products. In fact, a recurring finding in this review was that PBS is a very heterogeneous food category involving considerable variations in ingredient and nutrient composition, and whose design could be improved in order to foster nutritional and health benefits. The latter also depend on the animal food that is being replaced and are only deemed likely when PBS replace red meat. The fortification of PBS with key nutrients such as iron and calcium may constitute an actionable public health solution to further shift the balance in favour of PBS in the context of the current dietary transition in western countries.

The review aims to explore the potential benefit and risk of high-protein diets (HPD) regarding the comorbidity of sarcopoenia and CVD in the setting of cardiac rehabilitation (CR). CR is standard care for individuals who have experienced a cardiac event, but the current practice of predominantly aerobic exercise, a lower-fat diet and weight loss poorly addresses the issue of sarcopoenia. HPD, especially when combined with resistance exercise (RE), may be valuable adjuncts to current CR practice and benefit both muscle and cardiovascular health. Meta-analyses and randomised controlled trials of HPD and CVD risk show beneficial but variable effects regarding weight loss, the lipid profile, insulin resistance and lean body mass in those living with or high risk of CVD. Meta-analyses of prospective cohort studies on hard CVD endpoints favour lower- and plant-protein diets over higher animal protein, but the evidence is inconsistent. HPD augment the strength and muscle gaining benefits of RE in older populations, but there are no published data in those living with CVD providing promising opportunities for CR research. HPD raise concern regarding renal and bone health, the microbiome, branched chain amino acids and environmental sustainability and findings suggest that plant-based HPD may confer ecological and overall health advantages compared to animal-based HPD. However, incorporating RE with HPD might alleviate certain health risks. In conclusion, a largely plant-based HPD is deemed favourable for CR when combined with RE, but further research regarding efficacy and safety in CR populations is needed.