ISSN:1363-1950    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Purpose of reviewThis review critically evaluates recent studies investigating the effects of fatty acids on immune and inflammatory responses in both healthy individuals and in patients with inflammatory diseases, with some reference to animal studies where relevant. It examines recent findings describing the cellular and molecular basis for the modulation of immune function by fatty acids. The newly emerging area of diet-genotype interactions will also be discussed, with specific reference to the anti-inflammatory effects of fish oil.Recent findingsFatty acids are participants in many intracellular signalling pathways. They act as ligands for nuclear receptors regulating a host of cell responses, they influence the stability of lipid rafts, and modulate eicosanoid metabolism in cells of the immune system. Recent findings suggest that some or all of these mechanisms may be involved in the modulation of immune function by fatty acids.SummaryHuman studies investigating the relationship between dietary fatty acids and some aspects of the immune response have been disappointingly inconsistent. This review presents the argument that most studies have not been adequately powered to take into account the influence of variation (genotypic or otherwise) on parameters of immune function. There is well-documented evidence that fatty acids modulate T lymphocyte activation, and recent findings describe a range of potential cellular and molecular mechanisms. However, there are still many questions remaining, particularly with respect to the roles of nuclear receptors, for which fatty acids act as ligands, and the modulation of eicosanoid synthesis, for which fatty acids act as precursors.

ISSN:1363-1950    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Purpose of reviewTo evaluate the evidence with regard to high-versus low-fat diets in the context of the prevention and management of obesity, type 2 diabetes and coronary heart disease.Recent findingsDespite the increasing prevalence of obesity, there is no evidence to support the view that this is caused by an increased intake of fat. Fat sensors play an important role in regulating energy balance and lipid metabolism, and hypoenergetic diets containing 30-35% energy from fat promote weight loss. High intakes of carbohydrates with a high glycaemic index can result in insulin resistance, but this effect can be modulated by increased physical activity.SummaryAlthough arguments to decrease the intake of trans and saturated fatty acids are cogent, the scientific basis for a reduction in the proportion of energy from fat below 30% energy is not supported by experimental evidence. A modest reduction in fat intake to 30-35% energy, with the bulk of carbohydrates being derived from complex carbohydrates from unrefined sources, would appear to be the best option for the prevention of obesity and cardiovascular disease. Increased physical activity appears to be particularly important in modulating the adverse effects associated with high-carbohydrate low-fat diets.

ISSN:1363-1950    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Purpose of reviewLipid oxidation is the cause of important deteriorative changes in chemical, sensory and nutritional food properties. In particular, the question of whether oxidized fats in the diet may be detrimental to health is nowadays of the upmost concern, but finding an answer is not easy and requires careful consideration of different aspects of lipid oxidation.Recent findingsIn this review, the most recent works on the formation, nature and evaluation of oxidized dietary lipids are addressed; important issues such as the difficulties encountered in estimating their intake and the relationships between oxidants and antioxidants in the diet are discussed, and the latest studies on health implications of oxidized lipids are summarized.SummaryThe current literature reflects various important points. At present, there is no information on the intake of oxidized fats, which is essential to know if the amount of oxidized lipids in normal diets is sufficient to cause the physiological effects claimed. Recently, relevant advances in analytical methodologies for quantitation of specific oxidation compounds have been reported, although their application to improve the analytical definition of the oxidized substrate used in nutritional studies is still a goal to be reached. Alternatively, one of the most promising current tendencies in this field is the study of the molecular targets by which dietary oxidized lipids can influence health. Overall, more selected research based on coordinated multidisciplinary studies is needed to define the role of dietary oxidized fats in health.

ISSN:1363-1950    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Purpose of reviewThis review assesses the relative effect of fat versus carbohydrate and the differences between fatty acids and types of carbohydrate on insulin resistance and associated risk factors for diabetes and cardiovascular disease.Recent findingsThe debate continues over whether high-carbohydrate or high-fat diets have the more deleterious metabolic effects. Large randomized controlled trials have shown that a reduction of fat intake as part of a healthy lifestyle combined with weight reduction and exercise reduce the risk of type 2 diabetes. Carbohydrate as fruit and vegetable together with low-fat dairy products reduce blood pressure. The results of trials of fatty acid type continue to favor the use of monounsaturated fats. However, the advantages over carbohydrate have not always been clear. In terms of carbohydrate, the glycemic index appears to be a better predictor of the metabolic effects of a diet than the sugar content. The fiber content of the carbohydrate food appears to confer benefits in terms of diabetic control. Lower cholesterol and postprandial blood glucose results are associated with viscous fibers.SummaryDiets that are higher in monounsaturated fatty acids, fiber and low glycemic index foods appear to have advantages in insulin resistance, glycemic control and blood lipids in a number of studies. The division of nutrients into total fat (regardless of fatty acids) versus carbohydrate (type and quantity not specified) appears to be less helpful in predicting outcomes.

ISSN:1363-1950    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Purpose of reviewApolipoproteins and their receptors are the main controllers of lipid metabolism and, as such, have a major impact not only on the risk of cardiovascular disease but also on the development and degeneration of the central nervous system. Variations in the genes coding for these apolipoproteins and their receptors and the interaction with the environment determine individual susceptibility to metabolic disturbances, the response to dietary or pharmacological intervention and, finally, to disease.Recent findingsThis review will focus on recent findings, such as the latest concepts regarding apolipoprotein E in neurodevelopment, the newly identified apolipoprotein A-V and its influence in triglyceride metabolism, and the improved understanding of apolipoprotein A-I and HDL metabolism in the light of the discovery of the ABC family of transporters. Other key aspects of lipoprotein metabolism and cardiovascular disease risk such as apolipoprotein B-100, the LDL receptor, apolipoprotein C-III or apolipoprotein (a) will be updated.SummaryVariations in these genes will be analysed in relation to plasma lipid levels, their interactions with diet, treatment or other environmental stimuli, and their influence on the risk of cardiovascular disease and neurological disorders.

ISSN:1363-1950    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Purpose of reviewAfter two decades of intensive research, whether arginine-enriched diets for oral/enteral administration are beneficial or harmful for stressed patients remains uncertain. An American consensus and a meta-analysis provide divergent conclusions. The main goal of the present review is to analyze these documents.Recent findingsThe so-called immune-enhancing diets have been found to be beneficial to postoperative patients. Nothing proves, however, that arginine is responsible for these beneficial effects since immune-enhancing diets contain other pharmacologically active components (e.g. ω3 free fatty acids, RNAs, antioxidant vitamins). In fact, arginine-enriched diets may be harmful in hemodynamically unstable patients and those presenting with multiple organ failure.SummaryIn light of the current doubts and until convincing data are produced, immune-enhancing diets should not be used in unstable critically ill patients.

ISSN:1363-1950    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Purpose of reviewCardiovascular disease is one of the most important causes of morbidity and mortality in western countries, generating an increasing number of admissions to intensive care units. Cardiac failure has long been associated with nutritional disorders, malnutrition and cachexia being frequent during the late phases of congestive heart failure: undernutrition is also a determinant of outcome, even after cardiac transplantation.Recent findingsIt has been shown that early metabolic support can improve the recovery of the ischaemic heart. This paper reviews recent findings on substrates that can support the failing myocardium, which are mainly glucose-insulin, glutamine, taurine, selenium, thiamine, folic acid, and ω-3 fatty acids. Ischaemia-reperfusion generates tissue lesions that can be partly prevented through substrate manipulation.SummaryShifting the substrate metabolism from lipids to carbohydrates and reinforcing the antioxidant status reduces the deleterious biological and clinical consequences of acute ischaemic events. The use of the glucose-insulin-potassium infusion has become widespread with the re-discovery of its value in modulating cellular metabolism and accelerating recovery of the ischaemic myocardium. Antioxidants have gained acceptance in the perioperative phase, as well as in chronic heart failure. This constitutes another piece of evidence in favour of early metabolic and nutritional intervention. There also appears to be room for the prevention of acute deterioration of cardiac function after surgery with the preoperative administration of oral supplements containing ω-3 fatty acids.

ISSN:1363-1950    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Purpose of reviewInfection and sepsis remain major challenges in the critically ill. How nutritional therapy can effect real clinical outcomes is not easily apparent from the clinical data. Despite reducing infectious incidence, many studies show little difference in meaningful clinical outcomes.Recent findingsConfusion over the role that nutrition and nutrition practice in intensive care plays in preventing infection, and later how nutrition aids recovery from sepsis perhaps explains many of the misconceptions and difficulties with the evidence.SummaryEncouraging new evidence will help our decision making and shows that outcome can be improved by performing relatively simple therapies well.

ISSN:1363-1950    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Purpose of reviewThis review analyses the recently published literature focusing on nutritional assessment in intensive care unit patients. The metabolic response to nutritional intervention is difficult to evaluate in critically ill patients whose body weight is influenced largely by massive fluid administration or losses. Visceral protein plasma levels have been proposed for this purpose, because they reflect hepatic synthesis in response to nutrient supply. However, in acute inflammatory states, liver activity is converted to the synthesis of acute-phase response proteins, resulting in a dramatic drop in visceral proteins, despite nutritional support.Recent findingsThe data regarding visceral protein levels were examined in relation to nutritional supplementation, and compared with other nutritional parameters and clinical outcomes. Transthyretin and retinol-binding protein levels seem to be the most sensitive to nutritional intervention. They are also the earliest to rise at the decrease of acute-phase protein levels, therefore representing a good index of the reversing reprioritization of hepatic protein synthesis. An inconsistent relationship was found between visceral protein plasma levels and clinical outcome in intensive care unit patients, probably because of the difficulty in demonstrating clearly a beneficial effect of nutritional supplementation in highly catabolic conditions.SummaryIn the acute stage of critical illness, the bi-weekly measurement of transthyretin together with acute-phase response protein plasma levels seems to be a ‘window’ on the metabolic condition (anabolism versus catabolism). However, only in the presence of stable inflammatory parameters do transthyretin levels reflect the adequacy of nutritional coverage.

ISSN:1363-1950    

出版商:OVID    

年代:2003

数据来源: OVID