EC legislation requires the land to which free-range poultry have access to be ‘mainly covered with vegetation’, but the nature of this vegetation is not specified. In practice, most free-range land will be grass pasture. Modern poultry nutrition is a highly-developed science, and to house poultry in an environment in which they may consume an unknown quantity of vegetation, itself of unknown nutritive value, introduces uncertainty into a predictable system. In recent years the contribution of grazing to the nutrition of the birds has been considered negligible. However, birds on range appear to ingest a little grass, and therefore the quality of the pasture may affect their performance. If poultry consumed largely grass, then the nutritional value derived from it would be relatively poor. The grass would constitute a source of energy and fibre, but would make little contribution in terms of protein. The likely approach that poultry nutritionists would take is a precautionary one. They would need to know the full nutritive value of the pasture and the likely quantitative intake by the birds, and they would then make adjustments to feed formulations at what they considered to be a ‘safe’ level, in order to minimise the risks of impairing performance. A small (0–5) percentage contribution is probably the most that could be achieved, but given that feed accounts for about 70% of the variable costs of poultry production, such a contribution is economically important.

There have been substantial changes in the nutritional management of many diseases in the last 20 years, which have been accompanied by a growing recognition of its importance. Many of the changes in clinical nutrition have been associated with the introduction of standards, clinical audit and the implementation of evidence-based practice, which has led to a re-evaluation of some established dietary interventions using a hierarchy-of-evidence approach. Although there are few randomised controlled trials on which to base such work, the examination of other, often less-robust, evidence has led to some traditional dietary interventions being modified. Examples in gastroenterology include the use of low-fat diets in gall bladder disease and the restriction of protein in hepatic encephalopathy, where the current evidence suggests that neither should be used routinely in clinical practice. Where therapeutic dietary restrictions are required, as with low-Na diets in ascites, there is very little information on how these restrictions influence total nutrient intake and, if intake is impaired, how the detrimental effects of an inadequate intake should be balanced with the therapeutic effects of restriction. Studies are required to ensure that nutritional interventions are not only effective but also free from undesirable side effects. The mode and timing of the delivery of nutritional support has also been re-evaluated and the benefits of early enteral feeding have been recognised. The delivery of dietary advice is a new area that is being considered, with practitioners in clinical nutrition using behaviour-change skills to facilitate optimum nutrition rather than simply providing patients with advice. For such developments to continue in clinical nutrition it is essential that all practice should be systematically evaluated and, where necessary, modified in the light of sound current research findings, and that gaps in our present knowledge base are identified and addressed.

Currently the public is being inundated daily with information about diet and health, which is often conflicting and frequently not based on good quality evidence. This situation is fuelled by the ready access to information of variable quality via the internet, which has short circuited the previous checks and balances applied by researchers and the peer review process, whereby scientific findings were batted around and refined within the confines of the scientific research community, occasionally emerging to be incorporated into the advice given by health professionals. This situation, coupled with concern about the growing trend whereby detailed nutrition advice is sold to the public by self-styled 'experts' with no formal degree-level training in the subject, prompted a conference that highlighted the importance of ensuring that nutrition advice is evidence-based, using a series of topical overviews. In recent years the Nutrition Society has played an active role in establishing mechanisms to assist the public in their search for high-quality dietary advice by badging individuals appropriately qualified to offer sound and relevant advice on nutrition.

The domestic pig evolved from the omnivorous wild boar and has retained many natural foraging behaviour patterns. Although most modern commercial pigs are housed and fed concentrate diets, interest in the potential nutrient contribution from pasture has increased due to growth in outdoor and organic pig production systems. The energy requirements of outdoor pigs are increased by approximately 15% under Northern European conditions as a result of greater climatic energy demand and locomotory activity. The nutritional contribution made by pasture will depend on the availability, nutrient composition, grazing intake and digestive utilisation of herbage. Information on these topics is currently very sparse. Herbage availability is often low due to farm rotational policy or destructive foraging by the pigs. Herbage composition shows large varietal and seasonal differences, but the high fibre content reduces the efficiency of energy utilisation and may impair utilisation of other nutrients. Intake of grazed herbage varies widely between individuals, but is typically approximately 2.0 kg DM/d for dry sows fed restricted concentrate, and approximately 0.1 kg DM/d for growing pigs offered ad libitum concentrate. This intake can contribute 50% of the maintenance energy requirement and a high proportion of the amino acid, mineral and trace element requirements of dry sows, but <5% of requirements of growing pigs. Whilst the potential to increase nutrient intakes from grazing exists, this process requires better understanding of herbage intake and digestion, and development of better systems for paddock management.

Obesity is a serious health issue. In the UK the prevalence of obesity has trebled in the last 20 years and today one in five adults is clinically obese. Research shows that obesity is a predictable response to an environment that favours the consumption of energy-dense foods and allows minimal physical activity. This finding implies that the efficacy of public health messages to individuals to inform their lifestyle choices will be enhanced by environmental changes that support and facilitate healthy options. The present paper focuses on the importance of communicating scientific knowledge to the stakeholders with a responsibility for tackling obesity and addresses some of the barriers that are encountered.

As a clinically-effective nutritionist faced with needing to find the answer to a clinical question quickly it is necessary to search the best evidence efficiently. The requirements are to: (1) avoid having lots of papers to read; (2) be able to access this information at one's place of work; (3) restrict reading to trials and systematic reviews of trials. If a decision has to be made while on the ward, the best resource is probably an easy-to-use book, Clinical Evidence. This resource is also available on-line, but there may not be access to the Internet on the ward. If a little more time is available, and access to the Internet, the following plan is suggested: (1) work out what the question is and highlight the search terms; (2) using the best search engine available, search MEDLINE from 1990 for titles and abstracts of papers containing the search terms, this is the search strategy (limit the search by publication type by requesting randomised controlled trials only, English language only and human only); (3) if more or less than approximately ten hits are obtained, alter the limits of the search (not the search strategy); (4) read the abstract, or full paper where available, of the relevant hits and appraise this evidence.

The 'gold standard' method for the measurement of total dietary fibre is that of the Association of Official Analytical Chemists (2000; method 985.29). This procedure has been modified to allow measurement of soluble and insoluble dietary fibre, and buffers employed have been improved. However, the recognition of the fact that non-digestible oligosaccharides and resistant starch also behave physiologically as dietaryfibre has necessitated a re-examination of the definition of dietary fibre, and in turn, a re-evaluation of the dietary fibre methods of the Association of Official Analytical Chemists. With this realisation, the American Association of Cereal Chemists appointed a scientific review committee and charged it with the task of reviewing and, if necessary, updating the definition of dietary fibre. It organised various workshops and acceptedcomments from interested parties worldwide through an interactive website. More recently, the (US) Food and Nutrition Board of the Institute of Health, National Academy of Sciences, under the oversight of the Standing Committee on the Scientific Evaluation of Dietary Reference Intakes, assembled a panel to develop a proposed definition(s) of dietary fibre. Various elements of these definitions were in agreement, but not all. What was clear from both reviews is that there is an immediate need to re-evaluate the methods that are used for dietary fibre measurement and to make appropriate changes where required, and to find new methods to fill gaps. In this presentation, the 'state of the art' in measurement of total dietary fibre and dietary fibre components will be described and discussed, together with suggestions for future research.

The aim of our study was to investigate the relationship between dietary fibre intake and some clinical indices, blood biochemical variables and the incidence of cardiovascular disease and cancers in France, taking advantage of an ongoing cohort, the Supplementation en Vitamines et Minéraux AntioXydants (SU.VI.MAX) intervention study. This preliminary report provides data on dietary fibre intake in this French adult population group of 4080 subjects (2168 men and 1912 women) aged 45–65 years at inclusion. The data obtained for fibre intake indicate that most men and women have low to moderate intakes of total dietary fibre (mean 21·0 and 17·1 g/d respectively), with only 21% of the men and 7% of the women having total dietary fibre intakes at the recommended level (i.e. >25 g/d) and soluble fibre accounting for 19% of the total dietary fibre intake for both genders. The main food sources of dietary fibre are cereals (30–35% total), vegetables (20–24% total) and fruit (19–22% total). No marked regional differences were observed within France. The highest dietary fibre intakes have been found to be associated with a lower BMI, blood systolic pressure, plasma triacylglycerols and plasma glucose in men and lower BMI in women. Overall, these data support the concept of a beneficial effect of a high dietary fibre intake on cardiovascular disease risk.

Cardiovascular disease (CVD) is a leading cause of premature death in the UK and a major cause of ill health and disability. Whilst death rates from CVD have been falling since the late 1970's in the UK, levels of morbidity (such as angina) do not seem to be falling and may even be rising in some age-groups, especially as the population ages. There is broad consensus that lifestyle factors, including physical activity and diet, are fundamental determinants of heart disease risk. Current recommendations to reduce cardiovascular risk include maintaining a healthy body weight, eating five or more portions of fruit and vegetables each day, reducing intake of fat (particularly saturated fatty acids), reducing salt intake and eating one portion of oily fish per week. Although some improvements have been made in recent years (e.g. a reduction in total fat intake), national studies suggest that more effective campaigns are required to increase awareness of the benefits of these dietary changes. The present paper will discuss how the dietary messages relating to CVD are best communicated to the general public and will identify some of the main barriers to their implementation.

Common to both acute and chronic disease are disturbances in energy homeostasis, which are evidenced by quantitative and qualitative changes in dietary intake and increased energy expenditure. Negative energy balance results in loss of fat and lean tissue. The management of patients with metabolically-active disease appears to be simple; it would involve the provision of sufficient energy to promote tissue accretion. However, two fundamental issues serve to prevent nutritional demands in disease being met. The determination of appropriate energy requirements relies on predictive formulae. While equations have been developed for critically-ill populations, accurate energy prescribing in the acute setting is uncommon. Only 25–32% of the patients have energy intakes within 10% of their requirements. Clearly, the variation in energy expenditure has led to difficulties in accurately defining the energy needs of the individual. Second, the acute inflammatory response initiated by the host can have profound effects on ingestive behaviour, but this area is poorly understood by practising clinicians. For example, nutritional targets have been set for specific disease states, i.e. pancreatitis 105–147 KJ (25–35 kcal)/kg; chronic liver disease 147–168 kj (35–40 kcl)/kg, but given the alterations in gut physiology that accompany the acute-phase response, targets are unlikely to be met. In cancer cachexia attenuation of the inflammatory response using eicosapentaenoic acid results in improved nutritional intake and status. This strategy poses an attractive proposition in the quest to define nutritional support as a clinically-effective treatment modality in other disorders.

The main factors affecting the accumulation of potentially-toxic metals (PTM) by grazing animals are the presence of the metal, its concentration in herbage and at the soil surface, and the duration of exposure to the contaminated pasture and soil. In addition, the elapsed time between the contamination of the pasture and grazing, the quantity of soil ingested together with herbage, the mechanism of absorption of the metal into blood and the presence or absence of antagonistic metals can interact to influence the rate and extent of accumulation of heavy metals in edible body tissues. Models of the accumulation of metals by grazing animals may be used to determine the statutory limits of radionuclides and PTM in soils under grazed pastures. Meta-analysis of existing data, using a random-effects model, is a useful approach to understanding the factors affecting the accumulation of some metals, e.g. Cd. The target edible body tissues for the accumulation of most PTM are the liver and kidneys, with the exception of radiocaesium, which accumulates in muscle to a greater extent than in other tissues. The livers and kidneys of mature livestock that have been grazed on areas of pasture at the legal limit of contamination by Cd for more than one grazing season should be removed from the human food chain in order to reduce the risk of intake of Cd by the human population.

Weight loss is a frequent complication in patients with chronic obstructive pulmonary disease (COPD) and is a determining factor for functional capacity, health status and mortality. Weight loss in COPD is a consequence of an inbalance between increased energy requirements and dietary intake. Both metabolic and mechanical inefficiency may contribute to elevated energy expenditure during physical activity, while systemic inflammation has been associated with hypermetabolism at rest. Disease-specific symptoms and systemic inflammation may impair appetite and dietary intake. Altered intermediary metabolism may cause disproportionate wasting of fat-free mass in some patients. A combination of nutritional support and exercise as an anabolic stimulus appears to be the best approach to obtaining marked functional improvement. Patients responding to this treatment even demonstrated a decreased mortality. The effectiveness of anti-catabolic modulation requires further investigation.

There is very little evidence for the effects of dietary fibre in young children and current dietary guidelines are based on assumptions and data extrapolated from studies in adults. The first years of life may be critical for the establishment of a healthy colonic microflora, as well as good eating habits. The lack of clear and well-founded guidelines for the intake of dietary fibre in childhood may hinder both factors. The fears that a high-fibre diet in children <5 years of age will lead to growth faltering and mineral imbalance are not well supported in the literature, especially for children in the developed world. Indeed, with the rising levels of obesity, fibre intake may be of benefit in reducing energy intake. A low-fibre diet may also be implicated in the aetiology of childhood constipation and appendicitis. The latest proposals for the definition of dietary fibre include oligosaccharides, which may act as prebiotics. There are potential health benefits of including oligosaccharides in the diets of infants and children, but more research is needed to consider the long-term effects. The immature intestine of the infant may also result in a greater amount of starch entering the colon during weaning, and this starch would now be considered dietary fibre under the new definitions. Much new research is needed to allow adequate recommendations for the intake of dietary fibre in childhood based on data collected in appropriate age-groups.

The purpose of the present paper is to review our current understanding of the chemistry and biochemistry of folic acid and related folates, and to discuss their impact on public health beyond that already established in relation to neural-tube defects. Our understanding of the fascinating world of folates and C1 metabolism, and their role in health and disease, has come a long way since the discovery of the B-vitamin folic acid by Wills (1931), and its first isolation by Mitchell et al. (1941). However, there is still much to do in perfecting methods for the measurement of folate bioavailability, and status, with a high extent of precision and accuracy. Currently, examination of the relationships between common gene polymorphisms involved in C1 metabolism and folate bioavailability and folate status, morbidity, mortality and longevity is evaluated as a series of individual associations. However, in the future, examination of the concurrent effects of such common gene polymorphisms may be more beneficial.

Plant secondary metabolites are a natural resource that is largely unexploited in ‘conventional’ animal production systems. They have in the past been generally considered as a source of anti-nutritional factors, and not as a source of exploitable performance-enhancing compounds. Recent and continuing changes to legislation controlling the use of animal feed additives have stimulated interest in bioactive secondary metabolites as alternative performance enhancers. They are broadly compatible with current thinking on the future of agriculture and food in Europe, and with consumer opinion. Interest has been largely on their manipulative role in the digestive and absorptive processes of the hindgut. The present paper will review the use of plants and their extracts to manipulate the rumen microbial ecosystem to improve the efficiency of rumen metabolism. The bioavailability of secondary metabolites and their actions on peripheral metabolism will be considered with a view to improving animal performance. The challenge of delivering plants and their extracts to animals outdoors in a controlled manner will be discussed. Much of what is known about the beneficial roles of plant secondary metabolites on animal performance is circumstantial and is based on tenuous data. In order to more fully exploit their bioactive properties for the benefit of animal performance, modes of action need to be understood. Uptake will be dependent on proven efficacy and consumer acceptance of assurances relating to safety, welfare and the environment.

The epidemiological data that directly examine whole grain v. refined grain intake in relation to weight gain are sparse. However, recently reported studies offer insight into the potential role that whole grains may play in body-weight regulation due to the effects that the components of whole grains have on hormonal factors, satiety and satiation. In both clinical trials and observational studies the intake of whole-grain foods was inversely associated with plasma biomarkers of obesity, including insulin, C-peptide and leptin concentrations. Whole-grain foods tend to have low glycaemic index values, resulting in lower postprandial glucose responses and insulin demand. High insulin levels may promote obesity by altering adipose tissue physiology and by enhancing appetite. The fibre content of whole grains may also affect the secretion of gut hormones, independent of glycaemic response, that may act as satiety factors. Future studies may examine whether whole grain intake is directly related to body weight, and whether the associations are primarily driven by components of the grain, including dietary fibre, bran or germ.

The constraints to high levels of milk production imposed by a high-quality-pasture diet, and development of feeding strategies to overcome these limitations, were examined by modelling the nutritional status of New Zealand Friesian and North American Holstein–Friesian dairy cows grazing high-quality pasture. The Cornell Net Carbohydrate and Protein System (CNCPS) was used to predict sensitivity of milk production to a 10 % change in the composition of pasture nutrients. The rate at which fibre and protein were degraded in the rumen and the value given to effective fibre and lignin content significantly affected the supply of metabolisable energy and protein, and the profile of amino acid supply. The first limiting factor in milk production when only high-quality pasture was fed was metabolisable energy supply, while specific amino acids, particularly methionine and lysine, limited milk production when > 20 g/kg diet consisted of a grain supplement. Compared with cows fed a total mixed ration in confinement, North American Holstein–Friesians grazing all pasture produced less milk (29.6 v. 44.1 kg/d). Of the difference in milk production 61 % could be attributed to a lower DM intake (19 kg/d v. 23.4 kg/d). Predictions using the CNCPS indicated that supply of metabolisable energy was the first-limiting factor for milk production from high-quality pasture (251 g crude protein (N× 6.25)/kg, 432 g neutraldetergent fibre/kg, 77 % in vitro DM digestibility), rather than metabolisable protein or amino acids. In addition, these nutritional limitations imposed by pasture diets will be greater for dairy cow genotypes that have not been selected for high performance within a pasture system.

Cystic fibrosis (CF) is a genetically-inherited disorder that results in energy imbalance. Undernutrition is common in children with CF and associated with poor health outcomes. To ensure optimal growth and nutrition, children with CF are recommended to consume 120–150% of the recommended daily allowance (RDA) for energy, but most studies show they typically are only able to achieve 100% of the RDA. While biological factors clearly contribute to poor dietary adherence, recent studies have documented behavioural and environmental barriers to adherence that includes parent-child interaction at mealtimes. While not ‘abnormal’, parent behaviours such as paying increased attention to the child in the form of coaxing, commanding and feeding when the child is engaged in behaviours incompatible with eating (food refusal, talking, leaving the meal) may serve to reinforce these child non-eating behaviours. Thus, dietary counselling alone, albeit necessary, is typically insufficient because of failure to specifically address these behavioural and environmental barriers to dietary treatment. Behavioural intervention that targets both nutrition education and behavioural management has been found to be effective in achieving an average increased energy intake of 4200 kJ (1000)kcal/d and weight gain of 1·48 kg over 9 weeks in children with CF. This intervention utilizes self-monitoring, goal setting and shaping to structure the delivery of treatment. It also teaches parents to utilize child behaviour-management techniques to motivate children to increase their energy intake. These behavioural strategies include differential attention (praising and ignoring), contingency management and behavioural contracting. The potential application of these techniques to dietary counselling is suggested.

Epidemiological evidence suggests that diets rich in fruit and vegetables decrease the risk of premature mortality from major clinical conditions, including cancer and heart disease. However, it is not yet clear which components or combination of components in fruit and vegetables are protective and what is their mechanism of action. Such scientific uncertainty does not seem to inhibit the marketing of a huge range of plant-based concoctions, promoted as ‘magic bullets’ for optimum health. For example, the purported health-giving properties of plant polyphenols represent a case in which enthusiastic marketing claims may far exceed the current scientific evidence. Even when good experimental evidence exists, results need to be interpreted with caution in relation to human health benefits, as polyphenols may have limited bioavailability and may also be extensively metabolised. In addition, some polyphenols can be toxic and mutagenic in some cell culture systems. Until more is known about the activity and metabolic fate of polyphenols in the body, it would be better for the consumer to increase fruit and vegetable intake, and also to be wary of claims that these compounds are a panacea for good health.