Proceedings of the Nutrition Society
0029-6651
1475-2719
Anh Quốc
Cơ quản chủ quản: Cambridge University Press , CAMBRIDGE UNIV PRESS
Lĩnh vực:
Nutrition and DieteticsMedicine (miscellaneous)
Phân tích ảnh hưởng
Thông tin về tạp chí
Proceedings of the Nutrition Society publishes papers and abstracts presented by members and invited speakers at the scientific meetings of The Nutrition Society. The journal provides an invaluable record of the scientific research currently being undertaken, contributing to 'the scientific study of nutrition and its application to the maintenance of human and animal health.' The journal is of interest to academics, researchers and clinical practice workers in both human and animal nutrition and related fields.
Các bài báo tiêu biểu
Unsaturated fatty acids There is good scientific evidence that dietary fatty acid composition is involved in the aetiology of many diseases. Increasing the supply of n −3 polyunsaturated fatty acids (PUFA) may reduce the risk of CHD. Several scientific organizations (for example, see Department of Health, 1991, 1994; British Nutrition Foundation, 1992 ; Scientific Committee for Food, 1993 ; Food and Agriculture Organization/World Health Organization, 1998 ) have made recommendations for n −3 PUFA; however, there is a high degree of variation both in terms of the type and amount of n −3 PUFA (up to 7-fold). This variation reflects the different scientific axioms which underlie the different recommendations. Optimal nutrition may be defined in terms of the level of a nutrient required to avoid deficiency, or the amount required to have an effect on biomarkers and functional indicators of nutrient intake, or the level of a nutrient which prevents disease. Functional biomarkers of n −3 PUFA include plasma, platelet and erythrocyte phospholipid-n −3 PUFA levels. Plasma triacylglycerol concentrations represent a functional indicator of n −3 PUFA because n −3 PUFA exert a consistent hypotriacylglycerolaemic effect which is dose-dependent and persistent. In terms of disease status, epidemiological studies have demonstrated that the incidence of CHD is inversely associated with consumption of n −3 PUFA. Despite the health benefits of n −3 PUFA, the mean daily intake falls far short of most of the recommendations. Increasing fish intake is the most obvious way to increase n −3 PUFA intake. However, a large percentage (up to 65) of the population do not eat fish. Thus, there is a need for alternative sources of n −3 PUFA, such as functional foods, whose unique fatty acid composition could fortify staple foods thereby promoting optimal levels of n −3 PUFA intake.
Tập 58 Số 2 - Trang 397-401 - 1999
Role of adipose tissue in body-weight regulation: mechanisms regulating leptin production and energy balance Adipose tissue performs complex metabolic and endocrine functions. Among the endocrine products produced by adipose tissue are tumour necrosis factor α, interleukin 6, acylation-stimulating protein and leptin. The present review will focus primarily on mechanisms regulating leptin production and leptin action, and the implications of this regulation in the control of energy balance. Leptin acts in the central nervous system where it interacts with a number of hypothalamic neuropeptide systems to regulate feeding behaviour and energy expenditure. The presence of extreme obesity in animals and human subjects with mutations of the leptin gene or the leptin receptor demonstrates that normal leptin production and action are critical for maintaining energy balance. Insulin is the major regulator of leptin production by adipose tissue. Insulin infusions increase circulating leptin concentrations in human subjects. Plasma leptin levels are markedly decreased in insulin-deficient diabetic rodents, and the low leptin levels contribute to diabetic hyperphagia. Based onin vitro studies, the effect of insulin to stimulate leptin production appears to involve increased glucose metabolism. Blockade of glucose transport or glycolysis inhibits leptin expression and secretion in isolated adipocytes. Evidence suggests that anaerobic metabolism of glucose to lactate does not stimulate leptin production. Alterations in insulin-mediated glucose metabolism in adipose tissue are likely to mediate the effects of energy restriction to decrease, and refeeding to increase, circulating leptin levels. Changes in glucose metabolism may also explain the observation that high-fat meals lower 24 h circulating leptin levels relative to high-carbohydrate meals in human subjects, suggesting a mechanism that may contribute to the effects that high-fat diets have in promoting increased energy intake, weight gain and obesity. The decreased circulating leptin observed during energy restriction is related to increased sensations of hunger in human subjects. Thus, decreases in leptin during energy-restricted weight-loss regimens may contribute to the strong propensity for weight regain. A better understanding of the precise mechanisms regulating leptin production and leptin action may lead to new approaches for managing obesity.
Tập 59 Số 3 - Trang 359-371 - 2000
Fish, <i>n</i>-3 fatty acids, cognition and dementia risk: not just a fishy tale With growing and ageing populations, the incidence of dementia is expected to triple globally by 2050. In the absence of effective drugs to treat or reverse the syndrome, dietary approaches which prevent or delay disease onset have considerable population health potential. Prospective epidemiological studies and mechanistic insight from experimental models strongly support a positive effect of a high fish and long chain n -3 fatty acid (EPA and DHA) intake on a range of cognitive outcomes and dementia risk, with effect sizes equivalent to several years of ageing between the highest and lowest consumers. As reviewed here, an effect of EPA and DHA on neuroinflammation and oxylipin production is likely to in part mediate the neurophysiological benefits. However, randomised controlled trials (RCTs) with EPA and DHA supplementation have produced mixed findings. Insight into the likely modulators of response to intervention and factors which should be considered for future RCTs are given. Furthermore, the impact of APOE genotype on disease risk and response to EPA and DHA supplementation is summarised. The prevalence of dementia is several-fold higher in APOE4 females (about 13% Caucasian populations) relative to the general population, who are emerging as a subgroup who may particularly benefit from DHA intervention, prior to the development of significant pathology.
Tập 81 Số 1 - Trang 27-40 - 2022
Nutritional management of gut health in pigs around weaning Early weaning of piglets is often accompanied by a severe growth check and diarrhoea. It is well established that this process is multi-factorial and that post-weaning anorexia and undernutrition are major aetiological factors. Gastrointestinal disturbances include alterations in small intestine architecture and enzyme activities. Recent data indicate transiently-increased mucosal permeability, disturbed absorptive–secretory electrolyte balance and altered local inflammatory cytokine patterns after weaning. These responses appear to operate according to two distinct temporal patterns, an acute response followed by a long-lasting adaptation response. Pigs coexist with a diverse and dense commensal microbiota in their gastrointestinal tract. Most of these microbes are beneficial, providing necessary nutrients or protection against harmful pathogens for the host. The microbial colonisation of the porcine intestine begins at birth and follows a rapid succession during the neonatal and weaning period. Following the withdrawal of sow's milk the young piglets are highly susceptible to enteric diseases partly as a result of the altered balance between developing beneficial microbiota and the establishment of intestinal bacterial pathogens. The intestinal immune system of the newborn piglet is poorly developed at birth and undergoes a rapid period of expansion and specialisation that is not achieved before early (commercial) weaning. Here, new insights on the interactions between feed components, the commensal microbiota and the physiology and immunology of the host gastrointestinal tract are highlighted, and some novel dietary strategies are outlined that are focused on improving gut health. Prebiotics and probiotics are clear nutritional options, while convincing evidence is still lacking for other bioactive substances of vegetable origin.
Tập 66 Số 2 - Trang 260-268 - 2007
Physical activity and obesity prevention: a review of the current evidence Ecological data on temporal trends suggest that the rising prevalence of obesity is, at least in part, attributable to declining population energy expenditure. However, population-level data on trends in physical activity are scarce. In longitudinal cohort studies individuals who report higher levels of leisure-time physical activity tend to be less likely to gain weight, but studies vary in their conclusions because of issues of confounding, reverse causality and measurement error. The majority of studies suggest that low levels of activity are only weakly associated with future weight gain. Questions about dose–response can only be properly addressed by studies including objective measures of activity with known measurement error. The observational studies leave uncertainties about the direction of causality, as individuals who are overweight are less likely to stay active. Adjustment for confounding can diminish the impact of known confounders, but only randomisation can deal with issues of unmeasured confounding. Although there are a large number of clinical trials on the treatment of individuals with obesity or the prevention of weight regain among weight losers, the updated review of trials to prevent weight gain de novo only reveals six trials published since 2000 in adults and eleven in children. Not only are these trials relatively few in number but, for various methodological reasons, they are uncertain in their conclusions about whether increasing activity will be effective in preventing obesity. Whilst efforts should continue to enhance the evidence base it is wise, in the meantime, to stick to the consensus public health advice of advocating 45–60 min moderate intensity activity daily to prevent obesity.
Tập 64 Số 2 - Trang 229-247 - 2005
The challenges of control groups, placebos and blinding in clinical trials of dietary interventions
Tập 76 Số 4 - Trang 628-628 - 2017
The Second World Cancer Research Fund/American Institute for Cancer Research Expert Report. <i>Food, Nutrition, Physical Activity, and the Prevention of Cancer: A Global Perspective</i> It has been estimated by various authorities that about one-third of cancers in Western high-income societies are attributable to factors relating to food, nutrition and physical activity. Identifying with confidence specific associations between dietary patterns, foods, body composition or individual nutrients is not simple because of the long latent period for cancer development, its complex pathogenesis and the challenge of characterising the multidimensional aspects of diet and activity over a lifetime. Reliable conclusions must therefore be drawn not only from randomised controlled trials but from a variety of methodological approaches, judged within a classic framework for inferring causality. Using a newly-developed method with a protocol for standardising the literature search and for analysis and display of the evidence, nine independent academic centres have conducted systematic reviews addressing the causal associations between food, nutrition and physical activity and risk of development of seventeen cancers, as well as of weight gain and obesity. A review has also examined the efficacy of such interventions in subjects with cancer. The reviews have been assessed by an independent Panel of twenty-one international experts who drew conclusions with grades of confidence in the causality of associations and made recommendations. Recommendations are given as public health goals as well as for individuals.
Tập 67 Số 3 - Trang 253-256 - 2008
Oxidant stress: the role of nutrients in cell-lipoprotein interactions Oxidant stress is increasingly becoming an important hypothesis to explain the genesis of several pathologies, including cancer, atherosclerosis and also ageing. Beside a few rare genetic defects, dietary factors are thought to play a key role in the regulation of the production of reactive oxygenated species. An imbalance between nutrients, and in particular those involved in antioxidant status, could explain the onset of an enhanced production of free radicals. We will briefly review information concerning oxidation of lipids and lipoproteins which lead to atherothrombosis. We also present new findings supporting a role for blood platelets in generating oxidant species. New data are also described concerning the role of oxygenated derivatives of cholesterol, oxysterols, in cellular cholesterol efflux and NO production. Also, new developments relating to the influence of direct effects of free radicals on cellular cholesterol homeostasis are presented. Finally, the in vitro effects of butyrate, a natural short-chain fatty acid produced by bacterial fermentation, in the protection against free radical-mediated cytotoxicity are discussed. These data provide information on the mechanisms of dietary antioxidants in preventing oxidant stress.Résumé Au côté des rares cas d’origine génétique, les facteurs nutritionnels (déséquilibres alimentaires, déficience en nutriments antioxydants) jouent des rôles cruciaux dans la modulation de la production d’espèces actives de l’oxygène, conduisant à l’établissement d’un stress oxydant, situation métabolique de plus en plus reconnue comme susceptible d’être à l’origine de nombreuses pathologies comme les cancers, l’athérosclérose et également le vieillissement. Après avoir brièvement rappelé les données concernant l’oxydation des lipides et des lipoprotéines susceptibles de conduire au développement de l’athéro-thrombogenèse, nous présentons des données récentes et originales indiquant que les plaquettes sont en fait capables à l’instar d’autres cellules, de produire des formes actives de l’oxygène susceptibles de modifier les LDL. Des résultats originaux sont également exposés concernant l’effets des oxystérols, produits d’oxydation du cholestérol générés au cours de l’oxydation des LDL ou présents dans l’alimentation, sur deux paramètres importants comme l’efflux du cholestérol cellulaire et la production de monoxyde d’azote. De plus, des données nouvelles relatives à l’effets du stress oxydant et son inhibition par des antioxydants d’origine nutritionnelle sont exposées sur l’homéostasie du cholestérol cellulaire. Enfin, dans ce contexte, les effets potentiellement antiathérogènes d’un acide gras à courte chaîne produit par la fermentation bactérienne, le butyrate, sont décrits sur la protection de cellules en culture vis-à-vis d’un stress oxydant in vitro. Ces éléments contribuent à apporter de nouvelles informations renforçant la notion de fonctionnalité des nutriments dans la protection du stress oxydant en relation avec la pathogenèse.
Tập 58 Số 3 - Trang 559-563 - 1999
Linking biodiversity, diet and health in policy and practice Simplification of human diets associated with increased accessibility of inexpensive agricultural commodities and erosion of agrobiodiversity leads to nutrient deficiencies and excess energy consumption. Non-communicable diseases are growing causes of death and disability worldwide. Successful food systems in transition effectively draw on locally-available foods, food variety and traditional food cultures. In practice this process involves empirical research, public policy, promotion and applied action in support of multi-sectoral, community-based strategies linking rural producers and urban consumers, subsistence and market economies, and traditional and modern food systems. Implementation of the International Plant Genetic Resources Institute's Global Nutrition Strategy in Sub-Saharan Africa offers a useful case study. Relevant policy platforms, in which biodiversity conservation and nutrition are and should be linked, include the Millennium Development Goals, Millennium Ecosystem Assessment, Convention on Biological Diversity, Global Strategy on Diet, Physical Activity and Health, Food-Based Dietary Guidelines, Right to Adequate Food and UN Human Rights Commission's Permanent Forum on Indigenous Issues. The largely unexplored health benefits of cultivated and wild plants include micronutrient intake and functions related to energy density, glycaemic control, oxidative stress and immuno-stimulation. Research on the properties of neglected and underutilized species and local varieties deserves higher priority. In tests of the hypothesis that biodiversity is essential for dietary diversity and health, quantitative indicators of dietary and biological diversity can be combined with nutrition and health outcomes at the population level. That traditional systems once lost are hard to recreate underlines the imperative for timely documentation, compilation and dissemination of eroding knowledge of biodiversity and the use of food culture for promoting positive behaviours.
Tập 65 Số 2 - Trang 182-189 - 2006