Proceedings of the Nutrition Society最新文献

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 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.

Food systems in Africa are under pressure from climate change, conflicts, health pandemics such as COVID-19 and rising food prices. The COVID-19 pandemic highlighted weaknesses in global food systems and indeed Africa's was not spared. Although COVID-19 mortality and morbidity in Africa were relatively low in comparison to other regions, the containment measures employed by countries amplified a rather dire situation. Disruptions were seen in livelihoods, food value chains, increases in food prices and loss of income. These changes affected access to nutritious foods. A resilient food system that can withstand and recover from disruption and shocks will be important for ensuring access to healthy diets for all. This review paper assesses the state of food insecurity and malnutrition situation pre-COVID-19 and the impact of COVID-19 on Africa's food systems and access to healthy diet. To put Africa on a path to accelerated recovery, a resilient and sustainable food system will be crucial. The following recommendations are made: (i) increasing agriculture productivity, with special attention to the foods that contribute to healthy diets - fruits and vegetables, and animal source foods (ii) promoting the production and consumption of nutritious African traditional and indigenous foods (iii) transforming Africa's food systems to be gender-sensitive (iv) investing in well-targeted social protection programmes (v) supporting food environments that protect healthy diets and (vi) employing data and information to monitor food systems transformation.

The relationship between nutrition and ageing is complex. The metabolism and synthesis of micronutrients within the gut microbiome can influence human health but is challenging to study. Furthermore, studying ageing in humans is time-consuming and difficult to control for environmental factors. Studies in model organisms can guide research efforts in this area. This review describes how the nematode Caenorhabditis elegans can be used to study how bacteria and diet influence ageing and inform follow-on studies in humans. It is known that certain bacteria accelerate ageing in C. elegans. This age-accelerating effect is prevented by inhibiting folate synthesis within the bacteria, and we propose that in the human microbiome, certain bacteria also accelerate ageing in a way that can be modulated by interfering with bacterial folate synthesis. Bacterial-derived folates do not promote ageing themselves; rather, ageing is accelerated by bacteria in some way, either through secondary metabolites or other bacterial activity, which is dependent on bacterial folate synthesis. In humans, it may be possible to inhibit bacterial folate synthesis in the human gut while maintaining healthy folate status in the body via food and supplementation. The supplement form of folic acid has a common breakdown product that can be used by bacteria to increase folate synthesis. Thus, supplementation with folic acid may not be good for health in certain circumstances such as in older people or those with an excess of proteobacteria in their microbiome. For these groups, alternative supplement strategies may be a safer way to ensure adequate folate levels.

It is estimated that more than one-tenth of adults aged ≥60 years are now classified as having sarcopenic obesity (SO), a clinical condition characterised by the concurrent presence of sarcopenia (low muscle mass and weakness) and obesity (excessive fat mass). Independently, sarcopenia and obesity are associated with a high risk of numerous adverse health outcomes including CVD and neurological conditions (e.g. dementia), but SO may confer a greater risk, exceeding either condition alone. This imposes a substantial burden on individuals, healthcare systems and society. In recent years, an increasing number of observational studies have explored the association between SO and the risk of CVD; however, results are mixed. Moreover, the pathophysiology of SO is governed by a complex interplay of multiple mechanisms including insulin resistance, inflammation, oxidative stress, hormonal shifts and alteration of energy balance, which may also play a role in the occurrence of various CVD. Yet, the exact mechanisms underlying the pathological connection between these two complex conditions remain largely unexplored. The aim of this review is to examine the association between SO and CVD. Specifically, we seek to: (1) discuss the definition, epidemiology and diagnosis of SO; (2) reconcile previously inconsistent findings by synthesising evidence from longitudinal studies on the epidemiological link between SO and CVD and (3) discuss critical mechanisms that may elucidate the complex and potentially bidirectional relationships between SO and CVD.

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.

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.

Folate, vitamin B₁₂, vitamin B₆ and riboflavin interact by functioning as cofactors within one-carbon metabolism (OCM), a network of interrelated cellular pathways essential for numerous biological processes, including the biosynthesis of DNA, amino acid interconversions and methylation reactions. The pathways of OCM are influenced by endocrine signals and genetic polymorphisms and are particularly responsive to relevant B-vitamin intakes. Physiological changes in healthy pregnancy, leading to a steady decline in B-vitamin status, add another layer of complexity to the regulation of OCM. Although significant advances have been made to improve our understanding of these pregnancy-related changes, no specific reference ranges yet exist for B-vitamin biomarkers in pregnancy to support normal fetal growth without depleting maternal stores. The lack of pregnancy-related criteria for adequacy of B-vitamin status is in turn a major limitation in identifying pregnant women most at risk of B-vitamin deficiency. Another challenge is that the evidence is very limited to provide a basis for establishing pregnancy-specific dietary recommendations for B-vitamins to support successful pregnancy outcomes. In terms of preventing adverse outcomes, periconceptional folic acid supplementation has a proven role, established more than 30 years ago, in protecting against neural tube defect-affected pregnancies and this has been the major focus of public health policy worldwide. This review evaluates the emerging evidence for the less well recognised role of B-vitamins in preventing hypertensive disorders in pregnancy and the intergenerational effects of B-vitamins on offspring neurodevelopment and cognitive performance during childhood. We also consider the underlying biological mechanisms.

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.

Indicators of environmental impact can be used to inform the production, promotion and consumption of sustainable diets. Most environmental impacts associated with food production occur on farm; thus, sustainable diets are reliant on sustainable agricultural practices. In this paper, we review the current use of environmental indicators and metrics from global to local scales and highlight the need for locally relevant definitions to inform sustainable diets. Using Australia as a case study, we show that the diversity of food production systems is accompanied by a diversity of environmental issues, including climate change, land scarcity, nutrient pollution, water scarcity and biodiversity loss, each uniquely affecting different systems. However, while global datasets and indicators provide a consistent basis for estimating impacts and enabling country and food product comparisons, they often fail to capture the nuances of food production at national and sub-national scales. For example, land use may be a poor indicator of biodiversity loss when grazing a natural, low-input rangeland. Similarly, water use is only relevant where there is competition for the resource and eutrophication only where there is an adjacent water system to pollute. Thus, reporting frameworks used to inform sustainable diets need to be based on indicators that consider the context of local systems to demonstrate the clear linkage and how specific farming systems can drive sustainable diets. The development of provenance and traceability systems means the tools are already available to track impacts at a regional, or even individual farm, level.