Asthma is characterised by chronic lung airway inflammation, increased airway responsiveness and variable airflow obstruction. In Westernised countries asthma is a public health concern because of its prevalence, associated ill health and high societal and healthcare costs. In recent decades there has been a marked increase in asthma prevalence, particularly in Westernised countries. It has been proposed that changing diet has contributed to the increase in asthma. Several dietary hypotheses exist; the first relates the increase in asthma to declining dietary antioxidant intake, the second to decreased intake of long-chain n-3 PUFA and increasing intake of n-6 PUFA. Vitamin D supplementation and deficiency have also been hypothesised to have contributed to the increase in asthma. Observational studies have reported associations between asthma and dietary antioxidants (vitamin E, vitamin C, carotenoids, Se, flavonoids, fruit), lipids (PUFA, butter, margarine, fish) and vitamin D. However, supplementing the diets of adults with asthma with antioxidants and lipids has minimal, if any, clinical benefit. There is growing interest in the possibility that childhood asthma is influenced by maternal diet during pregnancy, with studies highlighting associations between childhood asthma and maternal intake of some nutrients (vitamin E, vitamin D, Se, PUFA) during pregnancy. It has been suggested that maternal diet during pregnancy influences fetal airway and/or immune development. Further intervention studies are needed to establish whether modification of maternal nutrient intake during pregnancy can be used as a healthy low-cost public health measure to reduce the prevalence of childhood asthma.

Food hypersensitivity (FHS) is the umbrella term used for food allergies that involve the immune system and food intolerances that do not involve the immune system. FHS has a huge impact on quality of life and any dietary advice given should aim to minimise this effect. Despite many advances made in diagnosing and managing patients with FHS, the cornerstone of management still remains avoidance of the relevant food. However, a commonly-presenting dilemma in clinical practice is deciding to what extent the food(s) should be avoided. The level of avoidance required is currently based on the type of FHS the patient has, characteristics of the particular food protein and the natural history of the particular FHS. In addition to management of other FHS, management of cow's milk allergy requires the healthcare professional to choose the appropriate formula. Information required by the patient also includes understanding food labels and issues surrounding cross-contamination. In order to ensure that the diet is nutritionally sound, advice should be given about suitable food choices and following a healthy balanced diet, whilst taking into account the dietary restrictions. Practical issues that need to be addressed include going on holiday, travelling and eating away from home. The dietitian plays a crucial role in this process. At present, there are no standardised documents or protocols for the management of FHS and practices differ within and between countries. If adrenaline auto-injectors are prescribed, correct administration should be demonstrated and reviewed on an ongoing basis.

Osteoporosis-related fractures have a major impact on health at the individual and societal levels, through associated morbidity and increased mortality. Up to 50% of women and 20% of men at age 50 years may have a fragility fracture in their remaining lifetimes. Nutrition is important throughout the life course. Thus, adequate Ca and vitamin D intake has been shown to reduce risk of fracture in old age. Other factors such as protein and vitamin K may also be important, although the evidence here is less strong. In childhood Ca or vitamin D supplementation trials have demonstrated modest short-term increases in bone mass, but the long-term implications have not been established. Over recent years it has become apparent that maternal nutrition may have critical and far-reaching persistent consequences for offspring health. Thus, reduced maternal fat stores and low levels of circulating 25-hydroxyvitamin D in pregnancy are associated with reduced bone mass in the offspring; placental Ca transport may be key to these relationships. Wider maternal dietary patterns have also been shown to predict offspring bone mass. These data suggest that an interventional approach aimed at specific micronutrients, such as vitamin D, should be complemented by general optimisation of the mother's diet and lifestyle in order to maximise intrauterine bone mineral accrual and postnatal skeletal growth and thus reduce the burden of osteoporotic fractures in future generations.

Treatments to induce weight loss for the obese patient centre on the achievement of negative energy balance. This objective can theoretically be attained by interventions designed to achieve a reduction in energy intake and/or an increase in energy expenditure. Such ‘lifestyle interventions’ usually comprise one or more of the following strategies: dietary modification; behaviour change; increases in physical activity. These interventions are advocated as first treatment steps in algorithms recommended by current clinical obesity guidelines. Medication and surgical treatments are potentially available to those unable to implement ‘lifestyle interventions’ effectively by achieving losses of between 5 kg and 10 kg. It is accepted that the minimum of 5% weight loss is required to achieve clinically-meaningful benefits. Dietary treatments differ widely. Successful weight loss is most often associated with quantification of energy intake rather than macronutrient composition. Most dietary intervention studies secure a weight loss of between 5 kg and 10 kg after intervention for 6 months, with gradual weight regain at 1 year where weight changes are 3–4 kg below the starting weight. Some dietary interventions when evaluated at 2 and 4 years post intervention report the effects of weight maintenance rather than weight loss. Specific anti-obesity medications are effective adjuncts to weight loss, in most cases doubling the weight loss of those given dietary advice only. Greater physical activity alone increases energy expenditure by insufficient amounts to facilitate clinically-important weight losses, but is useful for weight maintenance. Weight losses of between half and three-quarters of excess body weight are seen at 10 years post intervention with bariatric surgery, making this arguably the most effective weight-loss treatment.

CHD is the leading cause of worldwide mortality. The prevalence of heart disease has been linked to the adoption of a sedentary lifestyle and the increased dietary dependence on saturated fats from animal sources and the intake of refined foods. Elevated blood cholesterol level is one of the major risk factors for CHD. While cholesterol-lowering drug therapy (statins) has been effective in reducing the risk of heart disease, there are those individuals who are unwilling or because of muscle pains or raised levels of liver or muscle enzymes are unable to take cholesterol-lowering medication. Fortunately, there is evidence linking a number of dietary components to CHD risk reduction. The strength of this evidence has prompted various regulatory bodies to advocate diet as the first line of defence for primary prevention of heart disease. It was therefore decided to combine four dietary components that have been shown to lower blood cholesterol concentrations (nuts, plant sterols, viscous fibre and vegetable protein) in a dietary portfolio in order to determine whether the combined effect is additive. In a metabolically-controlled setting this dietary portfolio has proved to be as effective as a starting dose of a first-generation statin cholesterol-lowering medication in reducing the risk of CHD. The dietary portfolio has also been shown to be effective in sustaining a clinically-significant effect in the long term under a ‘real-world’ scenario. However, success of the diet depends on compliance and despite the accessibility of the foods adherence has been found to vary greatly. Overall, the evidence supports the beneficial role of the dietary portfolio in reducing blood cholesterol levels and CHD risk.

Diet is associated with the development of CHD. The incidence of CHD is lower in southern European countries than in northern European countries and it has been proposed that this difference may be a result of diet. The traditional Mediterranean diet emphasises a high intake of fruits, vegetables, bread, other forms of cereals, potatoes, beans, nuts and seeds. It includes olive oil as a major fat source and dairy products, fish and poultry are consumed in low to moderate amounts. Many observational studies have shown that the Mediterranean diet is associated with reduced risk of CHD, and this result has been confirmed by meta-analysis, while a single randomised controlled trial, the Lyon Diet Heart study, has shown a reduction in CHD risk in subjects following the Mediterranean diet in the secondary prevention setting. However, it is uncertain whether the benefits of the Mediterranean diet are transferable to other non-Mediterranean populations and whether the effects of the Mediterranean diet will still be feasible in light of the changes in pharmacological therapy seen in patients with CHD since the Lyon Diet Heart study was conducted. Further randomised controlled trials are required and if the risk-reducing effect is confirmed then the best methods to effectively deliver this public health message worldwide need to be considered.

Excess energy intake and positive energy balance are associated with the development of obesity and insulin resistance, which is a key feature underlying the pathophysiology of type 2 diabetes. It is possible that dietary macronutrient intake may also be important, in particular increased levels of sugar and fat. High-fat energy-dense diets contribute to energy excess and obesity. Fat type is also a factor, with evidence suggesting that saturated fat intake is linked to insulin resistance. However, controversy exists about the role of carbohydrate in the development of diabetes. Epidemiological studies suggest that the risk of diabetes is unrelated to the total amount of carbohydrate, but that fibre intake and glycaemic load are important. Common dietary advice for the prevention of diabetes often advocates complex carbohydrates and restriction of simple carbohydrates; however, sugars may not be the main contributor to glycaemic load. Evidence continues to emerge in relation to the influence of dietary sugars intake on insulin resistance. In broader dietary terms fruit and vegetable intake may influence insulin resistance, possibly related to increased intake of fibre and micronutrients or displacement of other food types. There is also considerable debate about the most effective diet and appropriate macronutrient composition to facilitate weight loss. Recent evidence suggests comparable effects of diets with varying macronutrient profiles on weight loss, which is predominantly related to energy restriction. However, based on the results of diabetes prevention trials focusing on lifestyle measures, evidence favours low-fat diets as the preferred approach for weight loss and diabetes prevention.

Obesity is a rapidly-growing public health problem that is related in part to the foods available in the eating environment. Properties of foods such as portion size and energy density (kJ/g) have robust effects on energy intake; large portions of energy-dense foods promote excess consumption and this effect starts in early childhood. Studies show, however, that in both adults and children these food characteristics can also be used strategically to moderate energy intake, as well as to improve diet quality. Dietary energy density can be reduced by increasing intake of water-rich foods such as vegetables and fruits. Their high water content allows individuals to eat satisfying portions of food while decreasing energy intake. Filling up at the start of a meal with vegetables or fruit and increasing the proportion of vegetables in a main course have been found to control hunger and moderate energy intake. Data from several clinical trials have also demonstrated that reducing dietary energy density by the addition of water-rich foods is associated with substantial weight loss even though participants eat greater amounts of food. Population-based assessments indicate that beginning in childhood there is a relationship between consuming large portions of energy-dense foods and obesity. These data suggest that the promotion of diets that are reduced in energy density should be an important component of future efforts to both prevent and treat obesity.

Successfully tackling obesity is a long-term commitment. Current levels of obesity in the population have been ≥30 years in the making. Not only will this position take time to reverse but there will be a considerable time lag before health and economic benefits are achieved through reductions in the morbidity from obesity-related diseases. There is clear evidence that policies aimed only at individuals will be inadequate and that increasing small-scale interventions will not suffice. Major action to prevent excess weight gain at a population level is required. The Foresight Report has confirmed that a ‘whole system’ approach is critical. This approach will require a broad portfolio of integrated policy responses including both national and local measures. This strategy requires action by government, both central and local, industry and communities and by families and the societies in which they live.

Epidemiological studies have provided convincing evidence that obesity increases the risk for cancers of the oesophagus (adenocarcinoma), colon, pancreas, breast (post-menopausal), endometrium and kidney. The magnitude of the increase in risk varies between cancer sites. For an increase in BMI of 10 kg/m2 relative risks are approximately 2·3 for adenocarcinoma of the oesophagus, 1·5 for colon cancer in men, 1·2 for colon cancer in women, 1·4 for post-menopausal breast cancer, 2·9 for endometrial cancer and >1·5 for kidney cancer, while the size of the effect on cancer of the pancreas is uncertain. There is also evidence that obesity increases the risks for cancers of the gallbladder, malignant melanoma, ovary, thyroid, non-Hodgkin lymphoma, multiple myeloma and leukaemia. Estimates of the percentage of cancers that can be attributed to excess body weight suggest that in the UK and similar countries approximately 5% of all cancers are attributable to overweight and obesity.

Dramatic advances have been made in the understanding of the differing molecular mechanisms used by nutrients to regulate genes that are essential for their biological roles to carry out normal metabolism. Classical studies have focused on nutrients as ligands to activate specific transcription factors. New interest has focused on histone acetylation as a process for either global or limited gene activation and is the first mechanism to be discussed. Nuclear ATP-citrate lyase generates acetyl-CoA, which has been shown to have a role in the activation of specific genes via selective histone acetylation. Transcription factor acetylation may provide a second mode of control of nutrient-responsive gene transcription. The third mechanism relates to the availability of response elements within chromatin, which as well as the location of the elements in the gene may allow or prevent transcription. A fourth mechanism involves intracellular transport of Zn ions, which can orchestrate localized enzyme inhibition–activation. This process in turn influences signalling molecules that regulate gene expression. The examples provided in the present review point to a new level of complexity in understanding nutrient–gene communication.

The present report discusses targeted and non-targeted approaches to monitor single nutrients and global metabolite profiles in nutritional research. Non-targeted approaches such as metabolomics allow for the global description of metabolites in a biological sample and combine an analytical platform with multivariate data analysis to visualise patterns between sample groups. In nutritional research metabolomics has generated much interest as it has the potential to identify changes to metabolic pathways induced by diet or single nutrients, to explore relationships between diet and disease and to discover biomarkers of diet and disease. Although still in its infancy, a number of studies applying this technology have been performed; for example, the first study in 2003 investigated isoflavone metabolism in females, while the most recent study has demonstrated changes to various metabolic pathways during a glucose tolerance test. As a relatively new technology metabolomics is faced with a number of limitations and challenges including the standardisation of study design and methodology and the need for careful consideration of data analysis, interpretation and identification. Targeted approaches are used to monitor single or multiple nutrient and/or metabolite status to obtain information on concentration, absorption, distribution, metabolism and elimination. Such applications are currently widespread in nutritional research and one example, using stable isotopes to monitor nutrient status, is discussed in more detail. These applications represent innovative approaches in nutritional research to investigate the role of both single nutrients and diet in health and disease.

Legally-binding legislation is now in place to ensure major reductions in greenhouse gas emissions in the UK. Reductions in intakes of meat and dairy products, which account for approximately 40% of food-related emissions, are an inevitable policy option. The present paper assesses, as far as is possible, the risk to nutritional status of such a policy in the context of the part played by these foods in overall health and well-being and their contribution to nutritional status for the major nutrients that they supply. Although meat may contribute to saturated fat intakes and a higher BMI, moderate meat consumption within generally-healthy population groups has no measurable influence on morbidity or mortality. However, high consumption of red and processed meat has been associated with increased risk of colo-rectal cancer and recent advice is to reduce intakes to a maximum of 70 g/d. Such reductions in meat and haem-Fe intake are unlikely to influence Fe status in functional terms. However, overall protein intakes would probably fall, with the potential for intakes to be less than current requirements for the elderly. Whether it is detrimental to health is uncertain and controversial. Zn intakes are also likely to fall, raising questions about child growth that are currently unanswerable. Milk and dairy products, currently specifically recommended for young children and pregnant women, provide 30–40% of dietary Ca, iodine, vitamin B12 and riboflavin. Population groups with low milk intakes generally show low intakes and poor status for each of these nutrients. Taken together it would appear that the reductions in meat and dairy foods, which are necessary to limit environmental damage, do pose serious nutritional challenges for some key nutrients. These challenges can be met, however, by improved public health advice on alternative dietary sources and by increasing food fortification.

Se is essential to human and animal health but can be toxic in excess. An interest in its geochemistry has developed alongside a greater understanding of its function in a number of health conditions. Geology exerts a strong control on the Se status of the surface environment; low-Se rock-types (0·05–0·09 mg Se/kg) make up the majority of rocks occurring at the Earth's surface, which in turn account for the generally low levels of Se in most soils. However, there are exceptions such as associations with sulfide mineralisation and in some types of sedimentary rocks (e.g. black shales) in which contents of Se can be much higher. Baseline geochemical data now enable a comparison to be made between environmental and human Se status, although a direct link is only likely to be seen if the population is dependent on the local environment for sustenance. This situation is demonstrated with an example from the work of the British Geological Survey in the Se-deficiency belt of China. The recent fall in the daily dietary Se intake in the UK is discussed in the context of human Se status and declining use of North American wheat in bread making. Generally, US wheat has ten times more Se than UK wheat, attributed to the fact that soils from the wheat-growing belt of America are more enriched in Se to a similar order of magnitude. In agriculture effective biofortification of crops with Se-rich fertilisers must be demonstrably safe to the environment and monitored appropriately and baseline geochemical data will enable this process to be done with confidence.

Iodine deficiency is not only a problem in developing regions; it also affects many industrialised countries. Globally, two billion individuals have an insufficient iodine intake, and approximately 50% of continental Europe remains mildly iodine deficient. Iodine intakes in other industrialised countries, including the USA and Australia, have fallen in recent years. Iodine deficiency has reappeared in Australia, as a result of declining iodine residues in milk products because of decreased iodophor use by the dairy industry. In the USA, although the general population is iodine sufficient, it is uncertain whether iodine intakes are adequate in pregnancy, which has led to calls for iodine supplementation. The few available data suggest that pregnant women in the Republic of Ireland and the UK are now mildly iodine deficient, possibly as a result of reduced use of iodophors by the dairy industry, as observed in Australia. Representative data on iodine status in children and pregnant women in the UK are urgently needed to inform health policy. In most industrialised countries the best strategy to control iodine deficiency is carefully-monitored salt iodisation. However, because approximately 90% of salt consumption in industrialised countries is from purchased processed foods, the iodisation of household salt only will not supply adequate iodine. Thus, in order to successfully control iodine deficiency in industrialised countries it is critical that the food industry use iodised salt. The current push to reduce salt consumption to prevent chronic diseases and the policy of salt iodisation to eliminate iodine deficiency do not conflict; iodisation methods can fortify salt to provide recommended iodine intakes even if per capita salt intakes are reduced to <5 g/d.

With the wide acceptance of the long-chain (LC) n-3 PUFA EPA and DHA as important nutrients playing a role in the amelioration of certain diseases, efforts to understand factors affecting intakes of these fatty acids along with potential strategies to increase them are vital. Widespread aversion to oil-rich fish, the richest natural source of EPA and DHA, highlights both the highly suboptimal current intakes in males and females across all age-groups and the critical need for an alternative supply of EPA and DHA. Poultry meat is a popular and versatile food eaten in large quantities relative to other meats and is open to increased LC n-3 PUFA content through manipulation of the chicken's diet to modify fatty acid deposition and therefore lipid composition of the edible tissues. It is therefore seen as a favourable prototype food for increasing human dietary supply of LC n-3 PUFA. Enrichment of chicken breast and leg tissue is well established using fish oil or fishmeal, but concerns about sustainability have led to recent consideration of algal biomass as an alternative source of LC n-3 PUFA. Further advances have also been made in the quality of the resulting meat, including achieving acceptable flavour and storage properties as well as understanding the impact of cooking on the retention of fatty acids. Based on these considerations it may be concluded that EPA- and DHA-enriched poultry meat has a very positive potential future in the food chain.

High blood pressure (BP) and elevated homocysteine are reported as independent risk factors for CVD and stroke in particular. The main genetic determinant of homocysteine concentrations is homozygosity (TT genotype) for the C677T polymorphism in the methylenetetrahydrofolate reductase (MTHFR) gene, typically found in approximately 10% of Western populations. The B-vitamins folate, vitamin B12 and vitamin B6 are the main nutritional determinants of homocysteine, with riboflavin more recently identified as a potent modulator specifically in individuals with the TT genotype. Although observational studies have reported associations between homocysteine and BP, B-vitamin intervention studies have shown little or no BP response despite decreases in homocysteine. Such studies, however, have not considered the MTHFR C677T polymorphism, which has been shown to be associated with BP. It has been shown for the first time that riboflavin is an important determinant of BP specifically in individuals with the TT genotype. Research generally suggests that 24 h ambulatory BP monitoring provides a more accurate measure of BP than casual measurements and its use in future studies may also provide important insights into the relationship between the MTHFR polymorphism and BP. Further research is also required to investigate the association between specific B-vitamins and BP in individuals with different MTHFR genotypes in order to confirm whether any genetic predisposition to hypertension is correctable by B-vitamin intervention. The present review will investigate the evidence linking the MTHFR C677T polymorphism to BP and the potential modulating role of B-vitamins.

There is growing evidence that consumption of a Western diet is a risk factor for osteoporosis through excess acid supply, while fruits and vegetables balance the excess acidity, mostly by providing K-rich bicarbonate-rich foods. Western diets consumed by adults generate approximately 50–100 mEq acid/d; therefore, healthy adults consuming such a diet are at risk of chronic low-grade metabolic acidosis, which worsens with age as a result of declining kidney function. Bone buffers the excess acid by delivering cations and it is considered that with time an overstimulation of this process will lead to the dissolution of the bone mineral content and hence to reduced bone mass. Intakes of K, Mg and fruit and vegetables have been associated with a higher alkaline status and a subsequent beneficial effect on bone health. In healthy male volunteers an acid-forming diet increases urinary Ca excretion by 74% and urinary C-terminal telopeptide of type I collagen (C-telopeptide) excretion by 19% when compared with an alkali (base-forming) diet. Cross-sectional studies have shown that there is a correlation between the nutritional acid load and bone health measured by bone ultrasound or dual-energy X-ray absorptiometry. Few studies have been undertaken in very elderly women (>75 years), whose osteoporosis risk is very pertinent. The EVAluation of Nutrients Intakes and Bone Ultra Sound Study has developed and validated (n 51) an FFQ for use in a very elderly Swiss population (mean age 80·4 (sd 2·99) years), which has shown intakes of key nutrients (energy, fat, carbohydrate, Ca, Mg, vitamin C, D and E) to be low in 401 subjects. A subsequent study to assess net endogenous acid production (NEAP) and bone ultrasound results in 256 women aged ≥75 years has shown that lower NEAP (P=0·023) and higher K intake (P=0·033) are correlated with higher bone ultrasound results. High acid load may be an important additional risk factor that may be particularly relevant in very elderly patients with an already-high fracture risk. The latter study adds to knowledge by confirming a positive link between dietary alkalinity and bone health indices in the very elderly. In a further study to complement these findings it has also been shown in a group of thirty young women that in Ca sufficiency an acid Ca-rich water has no effect on bone resorption, while an alkaline bicarbonate-rich water leads to a decrease in both serum parathyroid hormone and serum C-telopeptide. Further investigations need to be undertaken to study whether these positive effects on bone loss are maintained over long-term treatment. Mineral-water consumption could be an easy and inexpensive way of helping to prevent osteoporosis and could be of major interest for long-term prevention of bone loss.

Of the individuals who present with Crohn's disease 25% are <18 years of age, mostly adolescent. Nutritional impairment and delayed growth are common at diagnosis and remain an issue during the disease course. Treatment has the primary aim to control symptoms, induce disease remission and achieve normal growth in the long term and includes nutritional support and early use of immunomodulation. Puberty may be discordant and is generally late and final adult height may not be achieved until the late teenage years. Chronic ill health and delayed growth may be accompanied by emotional and intellectual immaturity. These factors, including the varying rates of physical and emotional development, need to be considered during adolescence with multidisciplinary input to ensure that the young patient is appropriately supported. Transition to adult care requires close collaboration between paediatric and healthcare teams with careful attention to nutritional, emotional and educational issues, all of which are relevant in the progression from childhood, through adolescence and to adult life.

The increased prevalence of CVD deaths in the past 60 years is a result in considerable part of the influence of environmental and lifestyle changes, including decreased daily energy expenditure through physical exertion. Physical activity prescription has therefore become an important public health issue. Exercise guidelines have evolved considerably since their first publication by the American College of Sports Medicine (ACSM) in 1978. Guidelines initially focused on moderate- to vigorous-intensity exercise to develop and maintain cardiorespiratory fitness. However, in the face of escalating physical inactivity, public health agencies sought to develop an exercise prescription more palatable to the sedentary majority and in 1995 recommended the accumulation of 30 min moderate-intensity exercise on most days of the week. The unexpected result of this message was that some individuals believed that vigorous exercise was not necessary, whilst others believed that low levels of physical activity were sufficient. In 2008 the ACSM and the American Heart Association sought to clarify this position and published an updated recommendation in which: the beneficial role of vigorous-intensity exercise is explicitly stated; adults are encouraged to combine moderate- and vigorous-intensity exercise to meet the minimum recommendation of moderate-intensity physical activity for a 30 min on 5 d/week or vigorous-intensity aerobic activity for 20 min on 3 d/week; the dose–response relationship between physical activity and health is reinforced. The immense challenge for public health professionals now lies in encouraging the sedentary population to adopt a more active lifestyle.