Mental, neurological and substance-use disorders presently represent the greatest global burden of disease. Likewise, depression and other psychopathologies are elevated risk comorbidities of other health hazards, such as obesity. Nutrition has been implicated in behaviour, mood and in the pathology and treatment of mental illness. In this brief editorial, we aim to set the scale of the problem in context and overview advances and recent evidence linking nutrition to psychological outcomes. The purpose of the 2016 Nutrition Society Winter Meeting, ‘Diet, nutrition and mental health and wellbeing’ was to review where the evidence is strong, where there are unmet needs for research and to draw together the communities working in this area to share their findings. The papers presented demonstrated clear advancements that are being made in this field. The meeting illustrated compelling support for nutrition as a modifiable risk factor. The present research in the field and evidence presented at the 2016 Nutrition Society Winter Meeting lead us to postulate that even interventions with relatively modest effect sizes may plausibly and significantly curtail the disease burden of mental and neurological disease by food- and nutrient-based approaches.

Mental illness, including depression, anxiety and bipolar disorder, accounts for a significant proportion of global disability and poses a substantial social, economic and heath burden. Treatment is presently dominated by pharmacotherapy, such as antidepressants, and psychotherapy, such as cognitive behavioural therapy; however, such treatments avert less than half of the disease burden, suggesting that additional strategies are needed to prevent and treat mental disorders. There are now consistent mechanistic, observational and interventional data to suggest diet quality may be a modifiable risk factor for mental illness. This review provides an overview of the nutritional psychiatry field. It includes a discussion of the neurobiological mechanisms likely modulated by diet, the use of dietary and nutraceutical interventions in mental disorders, and recommendations for further research. Potential biological pathways related to mental disorders include inflammation, oxidative stress, the gut microbiome, epigenetic modifications and neuroplasticity. Consistent epidemiological evidence, particularly for depression, suggests an association between measures of diet quality and mental health, across multiple populations and age groups; these do not appear to be explained by other demographic, lifestyle factors or reverse causality. Our recently published intervention trial provides preliminary clinical evidence that dietary interventions in clinically diagnosed populations are feasible and can provide significant clinical benefit. Furthermore, nutraceuticals including n-3 fatty acids, folate, S-adenosylmethionine, N-acetyl cysteine and probiotics, among others, are promising avenues for future research. Continued research is now required to investigate the efficacy of intervention studies in large cohorts and within clinically relevant populations, particularly in patients with schizophrenia, bipolar and anxiety disorders.

Observational studies and treatment trials investigating nutrition and cognitive function, with a focus on folate and soya and dementia, were reviewed. Data suggested that effects of folic acid based interventions may only be shown before cognitive decline is evident and/or if people are folate deficient. In older people in Indonesia, Hawai'i and China, tofu, which can contain high levels of phytoestrogens, was found to increase dementia risk. This association was not mediated by a vegetarian diet, socioeconomic status, formaldehyde, thyroid function, or loss of teeth. On the other hand, human observational and animal treatment studies suggested that tempe, a fermented soya product containing phytoestrogens and folate, reduced dementia risk and improved memory. High oestrogen levels were found to increase dementia risk in older women. However, in women with adequate serum folate, high oestrogen levels did not confer additional dementia risk and may protect ageing neurons. In conclusion, reviews seem to suggest that folic acid interventions are only effective on cognitive outcomes in people who are folate deficient and do not have cognitive impairment. Frequent consumption of tofu may have detrimental effects on memory and increase dementia risk in older East Asian people, while tempe may reduce these risks. Possibly folate in tempe offsets the potential negative effects of oestrogenic compounds on ageing neurons.

The relationship between obesity and cognitive impairment is important given the globally ageing population in whom cognitive decline and neurodegenerative disorders will carry grave individual, societal and financial burdens. This review examines the evidence for the link between obesity and cognitive function in terms of both the immediate effects on cognitive performance, and effects on the trajectory of cognitive ageing and likelihood of dementia. In mid-life, there is a strong association between obesity and impaired cognitive function. Anthropometric measures of obesity are also associated with reduced neural integrity (e.g. grey and white matter atrophy). Increasing age coupled with the negative metabolic consequences of obesity (e.g. type 2 diabetes mellitus) are likely to significantly contribute to cognitive decline and incidence of dementia. Stress is identified as a potential risk factor promoting abdominal obesity and contributing to impaired cognitive function. However, the potentially protective effects of obesity against cognitive decline in older age require further examination. Finally, surgical and whole diet interventions, which address obesity may improve cognitive capacity and confer some protection against later cognitive decline. In conclusion, obesity and its comorbidities are associated with impaired cognitive performance, accelerated cognitive decline and neurodegenerative pathologies such as dementia in later life. Interventions targeting mid-life obesity may prove beneficial in reducing the cognitive risks associated with obesity.

There is increasing evidence for important roles of key cognitive processes, including attention, memory and learning, in the short-term decision making about eating. There is parallel evidence that people who are overweight or obese tend to perform worse on a variety of cognitive tasks. In this review, the evidence for these two ideas is summarised and then the idea that overconsumption of Western-style high-fat (HF)–high-sugar diets may underlie the association between obesity and poorer cognitive performance is explored. In particular, evidence in animals and human subjects that repeated consumption of HF or HF and sugar (HFS) diets leads to specific impairments in the functioning of the hippocampus, which underpin the consequent changes in cognition is summarised. These findings lead into the vicious cycle model (VCM), which suggests that these cognitive changes have knock-on negative effects for future appetite control, and evidence that altered hippocampal function is also associated with impaired appetite control is explored. The review concludes that there is consistent evidence in the animal literature and emerging evidence from human studies that supports this VCM. It is also noted, however, that to date studies lack the nutritional specificity needed to be able to translate these basic research findings into clear nutritional effects, and concludes that there is an urgent need for additional research to clarify the precise nature of the apparent effects of consuming HFS diets on cognition.

The brain has a high metabolic rate and its metabolism is almost entirely restricted to oxidative utilisation of glucose. These factors emphasise the extreme dependence of neural tissue on a stable and adequate supply of glucose. Whereas initially it was thought that only glucose deprivation (i.e. under hypoglycaemic conditions) can affect brain function, it has become apparent that low-level fluctuations in central availability can affect neural and consequently, cognitive performance. In the present paper the impact of diet-based glycaemic response and glucose regulation on cognitive processes across the lifespan will be reviewed. The data suggest that although an acute rise in blood glucose levels has some short-term improvements of cognitive function, a more stable blood glucose profile, which avoids greater peaks and troughs in circulating glucose is associated with better cognitive function and a lower risk of cognitive impairments in the longer term. Therefore, a habitual diet that secures optimal glucose delivery to the brain in the fed and fasting states should be most advantageous for the maintenance of cognitive function. Although the evidence to date is promising, it is insufficient to allow firm and evidence-based nutritional recommendations. The rise in obesity, diabetes and metabolic syndrome in recent years highlights the need for targeted dietary and lifestyle strategies to promote healthy lifestyle and brain function across the lifespan and for future generations. Consequently, there is an urgent need for hypothesis-driven, randomised controlled trials that evaluate the role of different glycaemic manipulations on cognition.

Complex, diverse and rarely appearing without comorbidity, the autism spectrum disorders continue to be a source of research interest. With core symptoms variably impacting on social communication skills, the traditional focus of many research efforts has centred on the brain and how genetic and environmental processes impact on brain structure, function and/or connectivity to account for various behavioural presentations. Alongside emerging ideas on autistic traits being present in various clinical states, the autisms, and the overrepresentation of several comorbid conditions impacting on quality of life, other research avenues have opened up. The central role of the brain in relation to autism may be at least partially influenced by the functions of other organs. The gastrointestinal (GI) tract represents an important biological system pertinent to at least some autism. The notion of a gut–brain–behaviour axis has garnered support from various findings: an overrepresentation of functional and pathological bowel states, bowel and behavioural findings showing bidirectional associations, a possible relationship between diet, GI function and autism and recently, greater focus on aspects of the GI tract such as the collected gut microbiota in relation to autism. Gaps remain in our knowledge of the functions of the GI tract linked to autism, specifically regarding mechanisms of action onward to behavioural presentation. Set however within the context of diversity in the presentation of autism, science appears to be moving towards defining important GI-related autism phenotypes with the possibility of promising dietary and other related intervention options onward to improving quality of life.

Chronic pancreatitis is a chronic inflammatory disease of the pancreas characterised by irreversible morphological change and typically causing pain and/or permanent loss of function. This progressive, irreversible disease results in destruction of healthy pancreatic tissue and the development of fibrous scar tissue. Gradual loss of exocrine and endocrine function follows, along with clinical manifestations such as steatorrhoea, abdominal pain and diabetes. Nutrition in chronic pancreatitis has been described as a problem area and, until recently, there was little research on the topic. It is often asserted that >90 % of the pancreas must be damaged before exocrine insufficiency occurs; however, an exploration of the original studies from the 1970s found that the data do not support this assertion. The management of steatorrhoea with pancreatic enzyme replacement therapy is the mainstay of nutritional management, and early identification and treatment is a key. The presence of steatorrhoea, coupled with poor dietary intake (due to intractable abdominal pain, gastrointestinal side effects and often alcoholism) renders the chronic pancreatitis patients at considerable risk for undernutrition, muscle depletion and fat-soluble vitamin deficiency. Premature osteoporosis/osteopenia afflicts two-thirds of patients as a consequence of poor dietary intake of calcium and vitamin D, low physical activity, low sunlight exposure, heavy smoking, as well as chronic low-grade inflammation. Bone metabolism studies show increased bone formation as well as bone resorption in chronic pancreatitis, indicating that bone turnover is abnormally high. Loss of the pancreatic islet cells occurs later in the disease process as the endocrine cells are diffusely distributed throughout the pancreatic parenchyma. Patients may develop type 3c (pancreatogenic) diabetes, which is complicated by concurrent decreased glucagon secretion, and hence an increased risk of hypoglycaemia. Diabetes control is further complicated by poor diet, malabsorption and (for some) alcoholism, and therefore those with type 3c diabetes have clinical characteristics and therapeutic goals that are different from that of type 1 and type 2 diabetes patients. This review describes emerging research and clinical guidelines for nutrition in chronic pancreatitis.

Stable isotopes are non-radioactive, safe and are applied for various purposes in human health assessment in trace amounts that minimally disturb normal physiology. The International Atomic Energy Agency supports the use of stable isotope techniques to design and evaluate interventions addressing malnutrition in all its forms with focus on infant and young child feeding; maternal and adolescent nutrition; diet quality; prevention and control of non-communicable diseases; healthy ageing and gut function. These techniques can be used to objectively measure: (1) amount of human milk consumed and whether an infant is exclusively breastfed; (2) body composition in the context of re-feeding programmes for moderate and severe acute malnutrition and as an indicator of the risk for obesity; (3) bioavailability and bioconversion of pro-vitamin A and vitamin A body stores following vitamin A intervention programmes; (4) absorption and retention of iron, zinc and protein; (5) total energy expenditure for validation of physical activity measurement and dietary assessment tools and (6) diagnosis of Helicobacter pylori. Stable isotope techniques will be invaluable in the tracking of global targets on exclusive breast-feeding childhood obesity and anaemia among women. Efforts are underway to make nuclear techniques more affordable, field-friendly and less invasive, and to develop less sophisticated but precise equipment. Advocacy for the wide adoption of the techniques is needed.

Maternal and child health (MCH) consists of an interdependent reproductive system that collectively determines the survival of the mother during childbirth, and determines the health and survival of the child. This interdependency underscores the importance of appropriate and timely interventions during pregnancy through the first 1000 d at the minimum. The Millennium Development Goals (MDG) recommended the use of the continuum of care for the development of interventions by addressing all the stages of MCH. The purpose of the present paper is to review the factors that contributed to the attainment of the MDG 4 and MDG 5 by analysing the interventions conducted by the countries that achieved at least 5·0 and 5·5 %, respectively, and determine the level of their intervention based on the MCH conceptual framework. Out of the eighteen selected countries discussed, fifteen countries achieved their target for either MDG 4 or MDG 5 or both, while three countries did not achieve their target. The countries that were more likely to achieve their targets addressed the societal, underlying and direct causes, and implemented country wide policies. In contrast, the countries that did not succeed were more likely to address the direct causes with poor policy implementation. Understanding the motivation and limitations of the target population, including nutrition education and targeting behaviour change has the potential to result in sustainable MCH. This information has the potential to enlighten the policymakers as we progress to the sustainable development goals, specifically goals 2 and 3.

Social protection (SP) has been demonstrated as an effective tool against poverty and severe hunger. In Ghana, SP interventions have been employed to address vulnerability to poverty since 1965. Nevertheless, its potential for enhancing nutrition has hardly been explored. To harness the cross-sectoral benefits of scaling up nutrition-sensitive actions in Ghana, the national development planning commission requested an assessment of nutrition linkages across existing SP policies and programmes. The present paper presents gaps and opportunities for improving nutrition-sensitivity of existing SP programming in Ghana. The evidence draws heavily on desk review of available published and grey literature. The data show that SP provides an entry point for mainstreaming nutrition into other programmes. However, designing and coupling SP programmes with nutrition programmes remain a challenge in Ghana. Local SP interventions are predominantly designed as standalone services and therefore are implemented independent of each other. To increase synergy between SP and nutrition, including nutrition as an explicit objective of SP policies/strategies is recommended.

Addressing contemporary nutrition problems often requires application of knowledge from multiple disciplines. The scaling up nutrition (SUN) movement harnesses multiple sectors for effective global and in-country planning and implementation. Although the role of knowledge networks (academia and research institutions) is recognised, the how of engaging knowledge networks in the current SUN architecture is only now becoming apparent. For relevant sectors to play their roles effectively, observed capacity gaps, particularly in developing country settings, need to be addressed. The present paper presents the work being undertaken by the Ghana SUN Academic Platform (AP), a local knowledge network, towards strengthening nutrition capacity in Ghana. The AP presently provides technical support, evidence and capacity towards scaling up effective nutrition interventions in Ghana and beyond. The data presented draws heavily on the observations and collective experiences of the authors in practice, complemented by a review of relevant literature. The ultimate goal of the AP is to build capacity of professionals from nutrition and cognate sectors (including planning, agriculture, health, economics, research and academia). This is an essential ingredient for effective and durable SUN efforts. The paper recognises that both disciplinary and interdisciplinary capacity is required for effective SUN efforts in Africa, and offers an approach that utilises cross-sector/inter-professional, peer-learning and experiential learning initiatives.

Over the past two decades, increasing efforts have been made to find suitable nutritional products for managing particularly moderate forms of malnutrition following acute phase treatment, including the adoption of ready-to-use therapeutic foods. The challenge in meeting nutrient needs of normal growing young children and other vulnerable population groups with scant food supply has led us to explore the use of local, traditional and culturally adaptable food-based complementary foods employing the food multimix (FMM) concept. The present paper examined FMM as a concept to demonstrate how locally available composite complementary recipes were used to create highly nutritious recipes at low cost and improve nutrition among vulnerable individuals. The method employed a food-to-food fortification approach for recipe development making use of the ‘nutrient strengths’ of candidate ingredients. A range of different food recipes had been developed using a stepwise approach and combinations of foods from different populations and communities and packaged as 100 g recipe powders. Proximate and micronutrient analyses have been undertaken, optimised and the nutrient compositions compared with reference nutrient intakes for target groups. Examples of recipes and their nutrient profiles had been highlighted for different formulations showing different ingredients. Theoretical nutrient values were translated into practice based on data from intervention studies. The FMM approach using locally available food has held promise, and published evidence did indicate that the concept can contribute significantly to long-term food-based solutions to meeting nutrient needs of vulnerable groups in poor communities.

The Mediterranean dietary patterns comply better with recommended nutrient and micronutrient intakes. The Mediterranean diet (MD) was associated with reduced mortality and lower risk for metabolic chronic diseases. It has also low ecological, carbon and water footprints due to its high share of plant-based foods. In fact, the share of plant-based dietary energy is higher in the Mediterranean than in Northern Europe. The Mediterranean hotspot is a major centre of plant and crop diversity. Mediterranean people gather and consume about 2300 plant species. This review paper aims at highlighting the nutrition–health benefits of the MD and analysing the main environmental impacts of the Mediterranean food consumption patterns. There is a growing body of scientific evidence that the MD has significant health–nutrition benefits and low environmental footprints, so there is urgent need to reverse the ongoing erosion of the MD heritage and to promote it as a sustainable diets model.

Individual food consumption surveys (IFCS) are performed to evaluate compliance with food/nutrient intake requirements or exposure to potential harmful dietary contaminants/components. In this review, we inventoried methods and designs used in national IFCS and discussed the methodologies applied across countries. Literature searches were performed using fixed sets of search terms in different online databases. We identified IFCS in thirty-nine countries from six world continents. National IFCS systems are available in most of the high-income countries, while such surveys are scarce in low- and middle-income countries (e.g. Africa, Eastern Europe and several Asian countries). Few countries (n 9) have their national IFCS incorporated into national health and nutrition surveys, allowing the investigation of dietary-related disease outcomes. Of the integrated surveys, most have the advantage of being continuous/regular, contrary to other IFCS that are mostly erratic. This review serves as the basis to define gaps and needs in IFCS worldwide and assists in defining priorities for resource allocation. In addition, it can serve as a source of inspiration for countries that do not have an IFCS system in place yet and advocate for national IFCS to be incorporated into national health and nutrition surveys in order to create: (1) research opportunities for investigating diet–disease relationships and (2) a frame to plan and evaluate the effect of diet-related policies (e.g. promotion of local nutrient-rich foods) and of nutrition recommendations, such as food-based dietary guidelines. Countries that integrate their IFCS within their national health and nutrition survey can serve as proof-of-principle for other countries.

Although the literature on the contribution of DHA and arachidonic acid (ARA) to fundamental metabolic functions in brain, immune and cardiovascular systems is extensive, there is a lack of consensus on the need for explicit recommendations on dietary intake for both DHA and ARA during the early years of life. This review takes a public health perspective with the objective of ensuring that recommendations protect the most vulnerable children worldwide. Most studies on the effects of DHA and ARA in early life have been undertaken in high-income countries and this is reflected in policy recommendations. Although breast milk is considered the gold standard and always contains DHA and ARA, there are proposals that infant formulas, especially follow-on formulas, do not need to be supplemented with these fatty acids. Complementary foods frequently have low concentrations of ARA and DHA and this is most significant in low-income countries where availability is also limited. Recent evidence shows that in developing countries, intakes of DHA and ARA during the age period 6–36 months are low and this relates to low national income. It is concluded that a continuum of DHA and ARA intake needs to be maintained during early life, a critical period of infant growth and development. For both infant and follow-on formulas, DHA and ARA should be mandatory at levels that are equivalent to breast milk. An optional recommendation may be limited to countries that can demonstrate evidence of adequate intakes of DHA and ARA during early life.

Sub-Saharan Africa (SSA) has traditionally had a low life expectancy due to the onslaught of the HIV epidemic, high levels of chronic diseases, injuries, conflict and undernutrition. Therefore, research into public health concerns of older persons has largely been overlooked. With a growing population, the roll-out of antiretroviral treatment, and the effects of globalisation, SSA is experiencing an increase in the number of people over 50 years of age as well as an increase in the prevalence of non-communicable diseases (NCD). The aim of this review is to highlight available research on the health status of older persons in SSA, and to identify the current gaps that warrant further investigation. A literature search was conducted across multiple databases to identify studies in SSA on older persons (aged 50 years and older) related to health indicators including nutritional status, NCD and HIV burden. While it was concluded that older persons are at an increased risk of poor health, it was also determined that significant gaps exist in this particular area of research; namely nutrient deficiency prevalence. Resources should be directed towards identifying the health concerns of older persons and developing appropriate interventions.

The prevalence of stunting remains high in low- and middle-income countries despite adoption of comprehensive nutrition interventions, particularly in low-income countries. In the present paper, we review current evidence on the acceptability and efficacy of small-quantity lipid-based nutrient supplements (SQ-LNS) on preventing stunting in children under 2 years, discuss the factors that affect their efficacy, highlight the implications of the current findings at pragmatic level and identify research priorities. Although the present paper is not a generic systematic review, we used a systematic approach to select relevant literature. The review showed that there is growing interest in the potential benefits of using SQ-LNS to prevent growth faltering. Acceptability studies showed that SQ-LNS are generally well accepted. However, results on the efficacy of SQ-LNS on improving linear growth or preventing growth faltering in infants and young children are still inconclusive. Factors that may affect efficacy include the duration of the trial, composition and dosage of SQ-LNS given, and baseline demographics and nutritional status of research participants. Future research should focus on controlled and long-term follow-up trials to obtain more conclusive results. In the long term, there will be need for studies to investigate how provision of SQ-LNS can be integrated with existing strategies to prevent stunting in low- and middle-income settings.

Although substantial amount of nutrition research is conducted in Africa, the research agenda is mainly donor-driven. There is a clear need for a revised research agenda in Africa which is both driven by and responding to local priorities. The present paper summarises proceedings of a symposium on how evidence can guide decision makers towards context-appropriate priorities and decisions in nutrition. The paper focuses on lessons learnt from case studies by the Evidence Informed Decision Making in Nutrition and Health Network implemented between 2015 and 2016 in Benin, Ghana and South Africa. Activities within these countries were organised around problem-oriented evidence-informed decision-making (EIDM), capacity strengthening and leadership and horizontal collaboration. Using a combination of desk-reviews, stakeholder influence-mapping, semi-structured interviews and convening platforms, these country-level studies demonstrated strong interest for partnership between researchers and decision makers, and use of research evidence for prioritisation and decision making in nutrition. Identified capacity gaps were addressed through training workshops on EIDM, systematic reviews, cost–benefit evaluations and evidence contextualisation. Investing in knowledge partnerships and development of capacity and leadership are key to drive appropriate use of evidence in nutrition policy and programming in Africa.

Vitamin A is an essential micronutrient for life and the phytochemical β-carotene, also known as pro-vitamin A, is an important dietary source of this vitamin. Vitamin A (retinol) is the parent compound of all bioactive retinoids but it is retinoic acid (RA) that is the active metabolite of vitamin A. The plasma concentration of retinol is maintained in a narrow range and its normal biological activities strictly regulated since excessive intake can lead to toxicity and thus also be detrimental to life. The present review will give an overview of how vitamin A homeostasis is maintained and move on to focus on the link between circulating vitamin A and metabolic disease states. Finally, we will examine how pharmacological or genetic alterations in vitamin A homeostasis and RA-signalling can influence body fat and blood glucose levels including a novel link to the liver secreted hormone fibroblast growth factor 21, an important metabolic regulator.