当前期刊: Annual Review of Nutrition Go to current issue    加入关注   
显示样式:        排序: 导出
我的关注
我的收藏
您暂时未登录!
登录
  • The role of muscle insulin resistance in the pathogenesis of atherogenic dyslipidemia and nonalcoholic fatty liver disease associated with the metabolic syndrome.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2010-07-22
    François R Jornayvaz,Varman T Samuel,Gerald I Shulman

    The metabolic syndrome is a clustering of cardiovascular risk factors, including insulin resistance, abdominal obesity, dyslipidemia, and hypertension, and is associated with other comorbidities such as a proinflammatory state and nonalcoholic fatty liver disease (NAFLD). Its prevalence is high, especially among developed countries, and mainly reflects overnutrition and sedentary lifestyle. Moreover, the developing countries are not spared, as obesity and its related problems such as the metabolic syndrome are increasing quickly. We review the potential primary role of skeletal muscle insulin resistance in the pathophysiology of the metabolic syndrome, showing that in lean, young, insulin-resistant individuals, impaired muscle glucose transport and glycogen synthesis redirect energy derived from carbohydrate into hepatic de novo lipogenesis, promoting the development of atherogenic dyslipidemia and NAFLD. The demonstration of a link between skeletal muscle insulin resistance and the metabolic syndrome offers opportunities in targeting early defects in muscle insulin action in order to counteract the development of the disease and its related complications.

    更新日期:2019-11-01
  • Selenoproteins and cancer prevention.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2012-03-13
    Cindy D Davis,Petra A Tsuji,John A Milner

    The discovery of multiple selenoproteins has raised tantalizing questions about their role in maintaining normal cellular function. Unfortunately, many of these remain inadequately investigated. While they have a role in maintaining redox balance, other functions are becoming increasingly recognized. As the roles of these selenoproteins are further characterized, a better understanding of the true physiological significance of this trace element will arise. This knowledge will be essential in defining optimum intakes to achieve cellular homeostasis in order to optimize health, including a reduction in cancer, for diverse populations. Human variation in the response to selenium likely reflects significant interactions between the type and amounts of selenium consumed with the genome and a host of environmental factors including the totality of the diet, as discussed in this review.

    更新日期:2019-11-01
  • Mammalian selenium-containing proteins.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2001-05-26
    D Behne,A Kyriakopoulos

    Mammalian selenium-containing proteins can be divided into three groups: proteins containing nonspecifically incorporated selenium, specific selenium-binding proteins, and specific selenocysteine-containing selenoproteins. Selenoproteins with known functions identified so far include five glutathione peroxidases, two deiodinases, several thioredoxin reductases, and selenophosphate synthetase 2. Alternative splicing leads to a greater variety of selenoproteins, as was shown in the cases of a specific sperm nuclei glutathione peroxidase and some thioredoxin reductases. Selenoprotein P, selenoprotein W, a 15-kDa selenoprotein, an 18-kDa selenoprotein, and several selenoproteins identified in silico from nucleotide sequence databases were found to contain selenocysteine but their functions are not known. Gel electrophoretic separation of tissue samples from rats labeled in vivo with (75)Se showed the existence of further selenium-containing proteins.

    更新日期:2019-11-01
  • Responsiveness of selenoproteins to dietary selenium.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 1999-08-17
    C B Allan,G M Lacourciere,T C Stadtman

    Selenocysteine-containing enzymes that have been identified in mammals include the glutathione peroxidase family (GPX1, GPX2, GPX3, and GPX4), one or more iodothyronine deiodinases and two thioredixin reductases. Selenoprotein P, a glycoprotein that contains 10 selenocysteine residues per 43 kDa polypeptide and selenoprotein W, a 10 kDa muscle protein, are unidentified as to function. Levels of all of these selenocysteine-containing proteins in various tissues are affected to different extents by selenium availability. Increased amounts of selenoproteins observed in response to selenium supplementation were shown in several studies to correlate with increases in the corresponding mRNA levels. In general, selenoprotein levels in brain are less sensitive to dietary selenium fluctuation than the corresponding selenoprotein levels in other tissues.

    更新日期:2019-11-01
  • Itaconic Acid: The Surprising Role of an Industrial Compound as a Mammalian Antimicrobial Metabolite.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2015-05-15
    Thekla Cordes,Alessandro Michelucci,Karsten Hiller

    Itaconic acid is well known as a precursor for polymer synthesis and has been involved in industrial processes for decades. In a recent surprising discovery, itaconic acid was found to play a role as an immune-supportive metabolite in mammalian immune cells, where it is synthesized as an antimicrobial compound from the citric acid cycle intermediate cis-aconitic acid. Although the immune-responsive gene 1 protein (IRG1) has been associated to immune response without a mechanistic function, the critical link to itaconic acid production through an enzymatic function of this protein was only recently revealed. In this review, we highlight the history of itaconic acid as an industrial and antimicrobial compound, starting with its biotechnological synthesis and ending with its antimicrobial function in mammalian immune cells.

    更新日期:2019-11-01
  • Lactation and Maternal Cardio-Metabolic Health.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2016-05-06
    Cria G Perrine,Jennifer M Nelson,Jennifer Corbelli,Kelley S Scanlon

    Researchers hypothesize that pregnancy and lactation are part of a continuum, with lactation meant to "reset" the adverse metabolic profile that develops as a part of normal pregnancy, and that when lactation does not occur, women maintain an elevated risk of cardio-metabolic diseases. Several large prospective and retrospective studies, mostly from the United States and other industrialized countries, have examined the associations between lactation and cardio-metabolic outcomes. Less evidence exists regarding an association of lactation with maternal postpartum weight status and dyslipidemia, whereas more evidence exists for an association with diabetes, hypertension, and subclinical and clinical cardiovascular disease.

    更新日期:2019-11-01
  • Direct and Functional Biomarkers of Vitamin B6 Status.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2015-05-15
    Per Magne Ueland,Arve Ulvik,Luisa Rios-Avila,Øivind Midttun,Jesse F Gregory

    Measures of B6 status are categorized as direct biomarkers and as functional biomarkers. Direct biomarkers measure B6 vitamers in plasma/serum, urine and erythrocytes, and among these plasma pyridoxal 5'-phosphate (PLP) is most commonly used. Functional biomarkers include erythrocyte transaminase activities and, more recently, plasma levels of metabolites involved in PLP-dependent reactions, such as the kynurenine pathway, one-carbon metabolism, transsulfuration (cystathionine), and glycine decarboxylation (serine and glycine). Vitamin B6 status is best assessed by using a combination of biomarkers because of the influence of potential confounders, such as inflammation, alkaline phosphatase activity, low serum albumin, renal function, and inorganic phosphate. Ratios between substrate-products pairs have recently been investigated as a strategy to attenuate such influence. These efforts have provided promising new markers such as the PAr index, the 3-hydroxykynurenine:xanthurenic acid ratio, and the oxoglutarate:glutamate ratio. Targeted metabolic profiling or untargeted metabolomics based on mass spectrometry allow the simultaneous quantification of a large number of metabolites, which are currently evaluated as functional biomarkers, using data reduction statistics.

    更新日期:2019-11-01
  • Inflammation in alcoholic liver disease.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2012-04-25
    H Joe Wang,Bin Gao,Samir Zakhari,Laura E Nagy

    Frank Burr Mallory's landmark observation in 1911 on the histopathology of alcoholic liver disease (ALD) was the first identification of a link between inflammation and ALD. In this review, we summarize recent advances regarding the origins and roles of various inflammatory components in ALD. Metabolism of ethanol generates a number of metabolites, including acetate, reactive oxygen species, acetaldehyde, and epigenetic changes, that can induce inflammatory responses. Alcohol and its metabolites can also initiate and aggravate inflammatory conditions by promoting gut leakiness of microbial products, by sensitizing immune cells to stimulation, and by activating innate immune pathways, such as complement. Chronic alcohol consumption also sensitizes nonimmune cells, e.g., hepatocytes, to inflammatory signals and impairs their ability to respond to protective signals. Based on these advances, a number of inflammatory targets have been identified with potential for therapeutic intervention in ALD, presenting new opportunities and challenges for translational research.

    更新日期:2019-11-01
  • Regulation of Hepcidin by Erythropoiesis: The Story So Far.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2016-05-06
    Sant-Rayn Pasricha,Kirsty McHugh,Hal Drakesmith

    Hepcidin is the master regulator of systemic iron homeostasis, facilitating iron balance by controlling intestinal iron absorption and recycling. Hepcidin levels are suppressed when erythropoiesis is stimulated, for example following acute blood loss, appropriately enhancing cellular iron export to the plasma to support production of new red blood cells. However, persistent increased and ineffective erythropoiesis, for example in thalassemia, results in sustained elevations in iron absorption, which cause iron overload with associated organ toxicities. The ligands, receptors, and canonical pathways by which iron loading and inflammation upregulate hepcidin expression have been largely established. However, although several mechanisms have been proposed, the means by which erythropoiesis causes hepcidin suppression have been unclear. The erythroid-derived hormone erythroferrone appears to be a convincing candidate for the link between increased erythropoiesis and hepcidin suppression. If confirmed to be clinically and physiologically relevant in humans, potentiation or inhibition of erythroferrone activity could be a crucial pharmaceutical strategy.

    更新日期:2019-11-01
  • Addressing the Increased Expectations of Nutrition.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : null
    Rudi Balling,Patrick J Stover

    更新日期:2019-11-01
  • Dietary Fatty Acids and Their Potential for Controlling Metabolic Diseases Through Activation of FFA4/GPR120.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2015-07-18
    Trond Ulven,Elisabeth Christiansen

    It is well known that the amount and type of ingested fat impacts the development of obesity and metabolic diseases, but the potential for beneficial effects from fat has received less attention. It is becoming clear that the composition of the individual fatty acids in diet is important. Besides acting as precursors of potent signaling molecules, dietary fatty acids act directly on intracellular and cell surface receptors. The free fatty acid receptor 4 (FFA4, previously GPR120) is linked to the regulation of body weight, inflammation, and insulin resistance and represents a potential target for the treatment of metabolic disorders, including type 2 diabetes and obesity. In this review, we discuss the various types of dietary fatty acids, the link between FFA4 and metabolic diseases, the potential effects of the individual fatty acids on health, and the ability of fatty acids to activate FFA4. We also discuss the possibility of dietary schemes that implement activation of FFA4.

    更新日期:2019-11-01
  • Introduction.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2018-08-22
    Rudi Balling,Patrick J Stover

    更新日期:2019-11-01
  • The vitamin K-dependent carboxylase.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2005-07-14
    Kathleen L Berkner

    The vitamin K-dependent (VKD) carboxylase uses the oxygenation of vitamin K to convert glutamyl residues (Glus) to carboxylated Glus (Glas) in VKD proteins, rendering them active in a broad range of physiologies that include hemostasis, apoptosis, bone development, arterial calcification, signal transduction, and growth control. The carboxylase has a high-affinity site that selectively binds VKD proteins, usually through their propeptide, and also has a second low-affinity site of VKD protein interaction. Propeptide binding increases carboxylase affinity for the Glu substrate, and the coordinated binding of the VKD propeptide and Glu substrate increases carboxylase affinity for vitamin K and activity, possibly through a mechanism of substrate-assisted catalysis. Tethering of VKD proteins to the carboxylase allows clusters of Glus to be modified to Glas by a processive mechanism that becomes disrupted during warfarin therapy. Warfarin inhibits a vitamin K oxidoreductase that generates the reduced vitamin K cofactor required for continuous carboxylation and causes decreased carboxylase catalysis and increased dissociation of partially carboxylated, inactive VKD proteins. The availability of reduced vitamin K may also control carboxylation in r-VKD protein-expressing cells, where the amounts of reduced vitamin K are sufficient for full carboxylation of low, but not high, expression levels of VKD proteins, and where carboxylation is not improved by overexpression of r-carboxylase. This review discusses these recent advances in understanding the mechanism of carboxylation. Also covered is the identification of functional carboxylase residues, a brief description of the role of VKD proteins in mammalian and lower organisms, and the potential impact of quality control components on carboxylation, which occurs in the endoplasmic reticulum during the secretion of VKD proteins.

    更新日期:2019-11-01
  • Manganese Is Essential for Neuronal Health.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2015-05-15
    Kyle J Horning,Samuel W Caito,K Grace Tipps,Aaron B Bowman,Michael Aschner

    The understanding of manganese (Mn) biology, in particular its cellular regulation and role in neurological disease, is an area of expanding interest. Mn is an essential micronutrient that is required for the activity of a diverse set of enzymatic proteins (e.g., arginase and glutamine synthase). Although necessary for life, Mn is toxic in excess. Thus, maintaining appropriate levels of intracellular Mn is critical. Unlike other essential metals, cell-level homeostatic mechanisms of Mn have not been identified. In this review, we discuss common forms of Mn exposure, absorption, and transport via regulated uptake/exchange at the gut and blood-brain barrier and via biliary excretion. We present the current understanding of cellular uptake and efflux as well as subcellular storage and transport of Mn. In addition, we highlight the Mn-dependent and Mn-responsive pathways implicated in the growing evidence of its role in Parkinson's disease and Huntington's disease. We conclude with suggestions for future focuses of Mn health-related research.

    更新日期:2019-11-01
  • Sources and Functions of Extracellular Small RNAs in Human Circulation.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2016-05-25
    Joëlle V Fritz,Anna Heintz-Buschart,Anubrata Ghosal,Linda Wampach,Alton Etheridge,David Galas,Paul Wilmes

    Various biotypes of endogenous small RNAs (sRNAs) have been detected in human circulation, including microRNAs, transfer RNAs, ribosomal RNA, and yRNA fragments. These extracellular sRNAs (ex-sRNAs) are packaged and secreted by many different cell types. Ex-sRNAs exhibit differences in abundance in several disease states and have, therefore, been proposed for use as effective biomarkers. Furthermore, exosome-borne ex-sRNAs have been reported to elicit physiological responses in acceptor cells. Exogenous ex-sRNAs derived from diet (most prominently from plants) and microorganisms have also been reported in human blood. Essential issues that remain to be conclusively addressed concern the (a) presence and sources of exogenous ex-sRNAs in human bodily fluids, (b) detection and measurement of ex-sRNAs in human circulation, (c) selectivity of ex-sRNA export and import, (d) sensitivity and specificity of ex-sRNA delivery to cellular targets, and (e) cell-, tissue-, organ-, and organism-wide impacts of ex-sRNA-mediated cell-to-cell communication. We survey the present state of knowledge of most of these issues in this review.

    更新日期:2019-11-01
  • Stable Isotope Ratios as Biomarkers of Diet for Health Research.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2015-06-07
    Diane M O'Brien

    Diet is a leading modifiable risk factor for chronic disease, but it remains difficult to measure accurately due to the error and bias inherent in self-reported methods of diet assessment. Consequently, there is a pressing need for more objective biomarkers of diet for use in health research. The stable isotope ratios of light elements are a promising set of candidate biomarkers because they vary naturally and reproducibly among foods, and those variations are captured in molecules and tissues with high fidelity. Recent studies have identified valid isotopic measures of short- and long-term sugar intake, meat intake, and fish intake in specific populations. These studies provide a strong foundation for validating stable isotopic biomarkers in the general US population. Approaches to improve specificity for specific foods are needed; for example, by modeling intake using multiple stable isotope ratios or by isolating and measuring specific molecules linked to foods of interest.

    更新日期:2019-11-01
  • Iron Regulation of Pancreatic Beta-Cell Functions and Oxidative Stress.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2016-05-06
    Marie Balslev Backe,Ingrid Wahl Moen,Christina Ellervik,Jakob Bondo Hansen,Thomas Mandrup-Poulsen

    Dietary advice is the cornerstone in first-line treatment of metabolic diseases. Nutritional interventions directed at these clinical conditions mainly aim to (a) improve insulin resistance by reducing energy-dense macronutrient intake to obtain weight loss and (b) reduce fluctuations in insulin secretion through avoidance of rapidly absorbable carbohydrates. However, even in the majority of motivated patients selected for clinical trials, massive efforts using this approach have failed to achieve lasting efficacy. Less attention has been given to the role of micronutrients in metabolic diseases. Here, we review the evidence that highlights (a) the importance of iron in pancreatic beta-cell function and dysfunction in diabetes and (b) the integrative pathophysiological effects of tissue iron levels in the interactions among the beta cell, gut microbiome, hypothalamus, innate and adaptive immune systems, and insulin-sensitive tissues. We propose that clinical trials are warranted to clarify the impact of dietary or pharmacological iron reduction on the development of metabolic disorders.

    更新日期:2019-11-01
  • Disallowed and Allowed Gene Expression: Two Faces of Mature Islet Beta Cells.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2016-05-06
    Katleen Lemaire,Lieven Thorrez,Frans Schuit

    Glucose homeostasis greatly depends on the match between fluctuating insulin demands and adjusted rates of insulin secretion, which is the function of pancreatic beta cells. Emerging evidence suggests that when neonatal beta cells mature, they acquire two faces of differentiated function: an expected "visible face" that depends on specific beta cell proteins needed for regulated insulin release, but also a "hidden face" that represses ubiquitous proteins to prevent inappropriate beta cell function such as elevated basal hormone secretion or insulin release triggered by exercise. This review highlights this novel concept, and we first propose that hidden faces may also be relevant for other specialized tissue functions, such as ketogenesis in the liver. Next, we discuss three scenarios in which aberrant gene expression causes abnormal glucose-induced insulin release and the epigenetic regulation of the hidden face in beta cells. We conclude with perspectives for new research, including beta cell replacement to cure diabetes.

    更新日期:2019-11-01
  • Insulin signaling in the pancreatic beta-cell.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2008-05-17
    Ingo B Leibiger,Barbara Leibiger,Per-Olof Berggren

    The appropriate function of insulin-producing pancreatic beta-cells is crucial for the regulation of glucose homeostasis, and its impairment leads to diabetes mellitus, the most common metabolic disorder in man. In addition to glucose, the major nutrient factor, inputs from the nervous system, humoral components, and cell-cell communication within the islet of Langerhans act together to guarantee the release of appropriate amounts of insulin in response to changes in blood glucose levels. Data obtained within the past decade in several laboratories have revitalized controversy over the autocrine feedback action of secreted insulin on beta-cell function. Although insulin historically has been suggested to exert a negative effect on beta-cells, recent data provide evidence for a positive role of insulin in transcription, translation, ion flux, insulin secretion, proliferation, and beta-cell survival. Current insights on the role of insulin on pancreatic beta-cell function are discussed.

    更新日期:2019-11-01
  • Splanchnic regulation of glucose production.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2007-05-01
    John Wahren,Karin Ekberg

    The liver plays a key role for the maintenance of blood glucose homeostasis under widely changing physiological conditions. In the overnight fasted state, breakdown of hepatic glycogen and synthesis of glucose from lactate, amino acids, glycerol, and pyruvate contribute about equally to hepatic glucose production. Postprandial glucose uptake by the liver is determined by the size of the glucose load reaching the liver, the rise in insulin concentration, and the route of glucose delivery. Hepatic glycogen stores are depleted within 36 to 48 hours of fasting, but gluconeogenesis continues to provide glucose for tissues with an obligatory glucose requirement. Glucose output from the liver increases during exercise; during short-term intensive exertion, hepatic glycogenolysis is the primary source of extra glucose for skeletal muscle, and during prolonged exercise, hepatic gluconeogenesis becomes gradually more important in keeping with falling insulin and rising glucagon levels. Type 1 diabetes is accompanied by diminished hepatic glycogen stores, augmented gluconeogenesis, and increased basal hepatic glucose production in proportion to the severity of the diabetic state. The hyperglycemia of type 2 diabetes is in part caused by an overproduction of glucose from the liver that is secondary to accelerated gluconeogenesis.

    更新日期:2019-11-01
  • Leptin--much more than a satiety signal.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2000-08-15
    R B Harris

    Much attention has focused on the effects of leptin as a central satiety agent. There is now a significant amount of evidence that leptin is active in the periphery. This review focuses on the ability of leptin to modify insulin sensitivity, tissue metabolism, stress responses, and reproductive function. Leptin's effect on several of these systems is mediated via the hypothalamic-pituitary axis. Therefore, although in vitro studies provide evidence for direct effects on specific tissues and metabolic pathways, it is essential to consider the interactions between leptin and other regulatory factors in vivo. Little is known about the regulation of peripheral receptor expression or the production of binding proteins. Both of these factors determine the bioactivity of circulating leptin and have the potential to induce a peripheral resistance to leptin, similar to the central "leptin resistance" observed in obese subjects. Future research will clarify which of the endocrine and metabolic actions of peripheral leptin are of physiological relevance and which should be considered a pharmacological manipulation.

    更新日期:2019-11-01
  • Regulation of pigeon cropmilk secretion and parental behaviors by prolactin.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 1995-01-01
    N D Horseman,J D Buntin

    Prolactin stimulates the growth and development of specialized epithelial cells lining the cropsac of pigeons and doves (family Columbidae), leading to formation of "cropmilk," which is fed to the newly hatched squab. This system of milk feeding is unique among birds. To support the feeding of cropmilk, a complex array of behavioral adaptations are also supported by high levels of prolactin secretion in columbids during parenting. These specializations include elevated food intake (hyperphagia), nest attendance, and regurgitation feeding of the squab. Although prolactin is clearly important for these behavioral adaptations, the precise physiological and mechanistic bases for these behavioral effects remain controversial. The molecular mechanisms of prolactin action in the cropsac epithelium have been studied by cloning prolactin-induced genes, by cloning and expressing the pigeon prolactin receptor, and by analyzing the transcription factors that are activated after prolactin treatment. The avian (pigeon) prolactin receptor is a member of the cytokine receptor superfamily and uniquely contains a complete duplication of the extracellular ligand-binding domain. One of the early signal-transducing actions of prolactin in cropsac epithelium is the activation of signal transducer and activator of transcription (STAT) proteins via tyrosine phosphorylation. This fundamental signaling pathway is shared with mammalian prolactin target tissues. The convergent evolution of milk feeding and the behaviors that support parenting in columbids and mammals has depended on adaptation of both conserved mechanisms and divergent physiological processes.

    更新日期:2019-11-01
  • Mechanisms of action of nonglucose insulin secretagogues.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 1994-01-01
    Y Liang,F M Matschinsky

    Insulin release induced by nonglucose secretagogues is initiated from beta-cell by a wide variety of stimuli through specific receptors or binding sites. Activation of receptors in turn generates or enhances the cytosol levels of cAMP, cADPR, IP3, DAG, and AA. These second messengers then activate protein kinases, change the ion currents cross the cell membrane, and mobilize intracellular Ca2+, thereby increasing phosphorylated proteins in the cytosol and augmenting [Ca2+]i. These events trigger exocytotic discharge of insulin. The crucial steps in receptor-mediated stimulation-secretion coupling and their relationship to glucose-stimulated insulin release is summarized in Figure 1. At the present stage of research, the general processes of secretagogue binding to receptors, of generating second messengers, of activating several types of protein kinase, and of altering the membrane potential as well as cytosol calcium levels has been intensively studied and qualitatively clarified. However, we know little about the exact nature of substrates of different protein kinases and their function in the insulin secretion process. With the help of molecular biology and protein chemistry, we expect that this gap will be filled in the near future.

    更新日期:2019-11-01
  • Chemical senses in the release of gastric and pancreatic secretions.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 1982-01-01
    J G Brand,R H Cagan,M Naim

    更新日期:2019-11-01
  • Autophagy and Lipid Droplets in the Liver.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2015-06-17
    Nuria Martinez-Lopez,Rajat Singh

    Autophagy is a conserved quality-control pathway that degrades cytoplasmic contents in lysosomes. Autophagy degrades lipid droplets through a process termed lipophagy. Starvation and an acute lipid stimulus increase autophagic sequestration of lipid droplets and their degradation in lysosomes. Accordingly, liver-specific deletion of the autophagy gene Atg7 increases hepatic fat content, mimicking the human condition termed nonalcoholic fatty liver disease. In this review, we provide insights into the molecular regulation of lipophagy, discuss fundamental questions related to the mechanisms by which autophagosomes recognize lipid droplets and how ATG proteins regulate membrane curvature for lipid droplet sequestration, and comment on the possibility of cross talk between lipophagy and cytosolic lipases in lipid mobilization. Finally, we discuss the contribution of lipophagy to the pathophysiology of human fatty liver disease. Understanding how lipophagy clears hepatocellular lipid droplets could provide new ways to prevent fatty liver disease, a major epidemic in developed nations.

    更新日期:2019-11-01
  • Biologic mechanisms of the protective role of lutein and zeaxanthin in the eye.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2003-03-11
    Norman I Krinsky,John T Landrum,Richard A Bone

    The macular region of the primate retina is yellow in color due to the presence of the macular pigment, composed of two dietary xanthophylls, lutein and zeaxanthin, and another xanthophyll, meso-zeaxanthin. The latter is presumably formed from either lutein or zeaxanthin in the retina. By absorbing blue-light, the macular pigment protects the underlying photoreceptor cell layer from light damage, possibly initiated by the formation of reactive oxygen species during a photosensitized reaction. There is ample epidemiological evidence that the amount of macular pigment is inversely associated with the incidence of age-related macular degeneration, an irreversible process that is the major cause of blindness in the elderly. The macular pigment can be increased in primates by either increasing the intake of foods that are rich in lutein and zeaxanthin, such as dark-green leafy vegetables, or by supplementation with lutein or zeaxanthin. Although increasing the intake of lutein or zeaxanthin might prove to be protective against the development of age-related macular degeneration, a causative relationship has yet to be experimentally demonstrated.

    更新日期:2019-11-01
  • GUGULIPID: a natural cholesterol-lowering agent.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2003-03-11
    Nancy L Urizar,David D Moore

    The resin of the Commiphora mukul tree has been used in Ayurvedic medicine for more than 2000 years to treat a variety of ailments. Studies in both animal models and humans have shown that this resin, termed gum guggul, can decrease elevated lipid levels. The stereoisomers E- and Z-guggulsterone have been identified as the active agents in this resin. Recent studies have shown that these compounds are antagonist ligands for the bile acid receptor farnesoid X receptor (FXR), which is an important regulator of cholesterol homeostasis. It is likely that this effect accounts for the hypolipidemic activity of these phytosteroids.

    更新日期:2019-11-01
  • America's obesity: conflicting public policies, industrial economic development, and unintended human consequences.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2004-06-11
    James E Tillotson

    The chapter reviews the historical development and interactions of U.S. agricultural, economic, nutrition, and development policies relating to the creation of the commercial environment of social, economic, technological, and political factors that favor the development of American obesity.

    更新日期:2019-11-01
  • Dietary n-6 and n-3 fatty acid balance and cardiovascular health.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2004-06-11
    Vasuki Wijendran,K C Hayes

    Epidemiological and clinical studies have established that the n-6 fatty acid, linoleic acid (LA), and the n-3 fatty acids, linolenic acid (LNA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) collectively protect against coronary heart disease (CHD). LA is the major dietary fatty acid regulating low-density lipoprotein (LDL)-C metabolism by downregulating LDL-C production and enhancing its clearance. Further, the available mass of LA is a critical factor determining the hyperlipemic effects of other dietary fat components, such as saturated and trans fatty acids, as well as cholesterol. By contrast, n-3 fatty acids, especially EPA and DHA, are potent antiarryhthmic agents. EPA and DHA also improve vascular endothelial function and help lower blood pressure, platelet sensitivity, and the serum triglyceride level. The distinct functions of these two families make the balance between dietary n-6 and n-3 fatty acids an important consideration influencing cardiovascular health. Based on published literature describing practical dietary intakes, we suggest that consumption of ~6% en LA, 0.75% en LNA, and 0.25% en EPA + DHA represents adequate and achievable intakes for most healthy adults. This corresponds to an n-6/n-3 ratio of ~6:1. However, the absolute mass of essential fatty acids consumed, rather than their n-6/n-3 ratio, should be the first consideration when contemplating lifelong dietary habits affecting cardiovascular benefit from their intake.

    更新日期:2019-11-01
  • Identification of trace element-containing proteins in genomic databases.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2004-06-11
    Vadim N Gladyshev,Gregory V Kryukov,Dmitri E Fomenko,Dolph L Hatfield

    Development of bioinformatics tools provided researchers with the ability to identify full sets of trace element-containing proteins in organisms for which complete genomic sequences are available. Recently, independent bioinformatics methods were used to identify all, or almost all, genes encoding selenocysteine-containing proteins in human, mouse, and Drosophila genomes, characterizing entire selenoproteomes in these organisms. It also should be possible to search for entire sets of other trace element-associated proteins, such as metal-containing proteins, although methods for their identification are still in development.

    更新日期:2019-11-01
  • Sulfur amino acid metabolism: pathways for production and removal of homocysteine and cysteine.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2004-06-11
    Martha H Stipanuk

    Tissue concentrations of both homocysteine (Hcy) and cysteine (Cys) are maintained at low levels by regulated production and efficient removal of these thiols. The regulation of the metabolism of methionine and Cys is discussed from the standpoint of maintaining low levels of Hcy and Cys while, at the same time, ensuring an adequate supply of these thiols for their essential functions. S-Adenosylmethionine coordinately regulates the flux through remethylation and transsulfuration, and glycine N-methyltransferase regulates flux through transmethylation and hence the S-adenosylmethionine/S-adenosylhomocysteine ratio. Cystathionine beta-synthase activity is also regulated in response to the redox environment, and transcription of the gene is hormonally regulated in response to fuel supply (insulin, glucagon, and glucocorticoids). The H2S-producing capacity of cystathionine gamma-lyase may be regulated in response to nitric oxide. Cys is substrate for a variety of anabolic and catabolic enzymes. Its concentration is regulated primarily by hepatic Cys dioxygenase; the level of Cys dioxygenase is upregulated in a Cys-responsive manner via a decrease in the rate of polyubiquitination and, hence, degradation by the 26S proteasome.

    更新日期:2019-11-01
  • Bioactive compounds in nutrition and health-research methodologies for establishing biological function: the antioxidant and anti-inflammatory effects of flavonoids on atherosclerosis.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2004-06-11
    P M Kris-Etherton,M Lefevre,G R Beecher,M D Gross,C L Keen,T D Etherton

    Identifying bioactive compounds and establishing their health effects are active areas of scientific inquiry. There are exciting prospects that select bioactive compounds will reduce the risk of many diseases, including chronic diseases such as cardiovascular disease. Recent findings have established that cardiovascular disease is a disease of inflammation, and consequently is amenable to intervention via molecules that have anti-inflammatory effects. In addition, research demonstrating adverse effects of oxidants on atherogenesis raises the possibility that antioxidants can confer cardioprotective effects. This review provides an overview of research approaches that can be used to unravel the biology and health effects of bioactive compounds. Because of the number of bioactive compounds and the diversity of likely biological effects, numerous and diverse experimental approaches must be taken to increase our understanding of the biology of bioactive compounds. Recognizing the complexity of this biology, sophisticated experimental designs and analytical methodologies must be employed to advance the field. The discovery of novel health effects of bioactive compounds will provide the scientific basis for future efforts to use biotechnology to modify/fortify foods and food components as a means to improve public health.

    更新日期:2019-11-01
  • Extracellular thiols and thiol/disulfide redox in metabolism.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2004-06-11
    Siobhan E Moriarty-Craige,Dean P Jones

    Many proteins present on cell surfaces and located in extracellular fluids contain cysteine and methionine residues that are subject to oxidation. These proteins, which include transporters, receptors, and enzymes, respond to variations in the extracellular thiol/disulfide redox environment. Changes in activity of these proteins can alter the ability of organs to function normally and influence processes such as nutritional absorption, secretory function, neurotransmission, and susceptibility to toxicants. In addition, extracellular redox can regulate tissue homeostasis through effects on cell proliferation, differentiation, apoptosis, and immune function. Consequently, extracellular redox can have important influences on health status and disease states and thus could be a target for nutritional interventions.

    更新日期:2019-11-01
  • Environmental factors that increase the food intake and consumption volume of unknowing consumers.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2004-06-11
    Brian Wansink

    Package size, plate shape, lighting, socializing, and variety are only a few of the environmental factors that can influence the consumption volume of food far more than most people realize. Although such environmental factors appear unrelated, they generally influence consumption volume by inhibiting consumption monitoring and by suggesting alternative consumption norms. For researchers, this review suggests that redirecting the focus of investigations to the psychological mechanisms behind consumption will raise the profile and impact of research. For health professionals, this review underscores how small structural changes in personal environments can reduce the unknowing overconsumption of food.

    更新日期:2019-11-01
  • Nutrient regulation of cell cycle progression.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2004-06-11
    Brenda L Bohnsack,Karen K Hirschi

    Cell replication is tightly controlled in normal tissues and aberrant during disease progression, such as in tumorigenesis. The replication of cells can be divided into four distinct phases: Gap 1 (G1), synthesis (S), gap 2 (G2), and mitosis (M). The progression from one phase to the next is intricately regulated and has many "checkpoints" that take into account cellular status and environmental cues. Among the modulators of cell cycle progression are specific nutrients, which function as energy sources or regulate the production and/or function of proteins needed to advance cells through a replicative cycle. In this review, we focus on the roles of specific nutrients (vitamin A, vitamin D, iron, folic acid, vitamin B12, zinc, and glucose) in the control of cell cycle progression and discuss how insights into the mechanisms by which these nutrients modulate this process can be and have been used to control aberrant cell growth in the treatment of prevalent pathologies.

    更新日期:2019-11-01
  • Secular trends in dietary intake in the United States.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2004-06-11
    Ronette R Briefel,Clifford L Johnson

    This review focuses on dietary intake and dietary supplement use among the U.S. population age 1-74 based on four National Health and Nutrition Examination Surveys conducted in 1971-74, 1976-80, 1988-94, and 1999-2000. Secular trends in intake of energy, macronutrients, cholesterol, sodium, calcium, iron, folate, zinc, vitamins A and C, fruits, vegetables, and grain products are summarized. During the 30-year period, mean energy intake increased among adults, and changed little among children age 1-19, except for an increase among adolescent females. Factors contributing to increases in energy intake include increases in the percentage of the population eating away from home (particularly at fast-food restaurants), larger portion sizes of foods and beverages, increased consumption of sweetened beverages, changes in snacking habits, and improved dietary methodology. Dietary supplement use increased among adult men and women, decreased among children age 1-5, and was stable for children age 6-11 and adolescents.

    更新日期:2019-11-01
  • Structure, function, and dietary regulation of delta6, delta5, and delta9 desaturases.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2004-06-11
    Manabu T Nakamura,Takayuki Y Nara

    Fatty acid desaturases introduce a double bond in a specific position of long-chain fatty acids, and are conserved across kingdoms. Degree of unsaturation of fatty acids affects physical properties of membrane phospholipids and stored triglycerides. In addition, metabolites of polyunsaturated fatty acids are used as signaling molecules in many organisms. Three desaturases, Delta9, Delta6, and Delta5, are present in humans. Delta-9 catalyzes synthesis of monounsaturated fatty acids. Oleic acid, a main product of Delta9 desaturase, is the major fatty acid in mammalian adipose triglycerides, and is also used for phospholipid and cholesteryl ester synthesis. Delta-6 and Delta5 desaturases are required for the synthesis of highly unsaturated fatty acids (HUFAs), which are mainly esterified into phospholipids and contribute to maintaining membrane fluidity. While HUFAs may be required for cold tolerance in plants and fish, the primary role of HUFAs in mammals is cell signaling. Arachidonic acid is required as substrates for eicosanoid synthesis, while docosahexaenoic acid is required in visual and neuronal functions. Desaturases in mammals are regulated at the transcriptional level. Reflecting overlapping functions, three desaturases share a common mechanism of a feedback regulation to maintain products in membrane phospholipids. At the same time, regulation of Delta9 desaturase differs from Delta6 and Delta5 desaturases because its products are incorporated into more diverse lipid groups. Combinations of multiple transcription factors achieve this sophisticated differential regulation.

    更新日期:2019-11-01
  • Iron, ferritin, and nutrition.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2004-06-11
    Elizabeth C Theil

    Ferritin, a major form of endogenous iron in food legumes such as soybeans, is a novel and natural alternative for iron supplementation strategies where effectiveness is limited by acceptability, cost, or undesirable side effects. A member of the nonheme iron group of dietary iron sources, ferritin is a complex with Fe3+ iron in a mineral (thousands of iron atoms inside a protein cage) protected from complexation. Ferritin illustrates the wide range of chemical and biological properties among nonheme iron sources. The wide range of nonheme iron receptors matched to the structure of the iron complexes that occurs in microorganisms may, by analogy, exist in humans. An understanding of the chemistry and biology of each type of dietary iron source (ferritin, heme, Fe2+ ion, etc.), and of the interactions dependent on food sources, genes, and gender, is required to design diets that will eradicate global iron deficiency in the twenty-first century.

    更新日期:2019-11-01
  • Vitamin B12 deficiency as a worldwide problem.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2004-06-11
    Sally P Stabler,Robert H Allen

    Pernicious anemia is a common cause of megaloblastic anemia throughout the world and especially in persons of European or African descent. Dietary deficiency of vitamin B12 due to vegetarianism is increasing and causes hyperhomocysteinemia. The breast-fed infant of a vitamin B12-deficient mother is at risk for severe developmental abnormalities, growth failure, and anemia. Elevated methylmalonic acid and/or total homocysteine are sensitive indicators of vitamin B12-deficient diets and correlate with clinical abnormalities. Dietary vitamin B12 deficiency is a severe problem in the Indian subcontinent, Mexico, Central and South America, and selected areas in Africa. Dietary vitamin B12 deficiency is not prevalent in Asia, except in vegetarians. Areas for research include intermittent vitamin B12 supplement dosing and better measurements of the bioavailability of B12 in fermented vegetarian foods and algae.

    更新日期:2019-11-01
  • Reprogramming of the immune system during zinc deficiency.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2004-06-11
    Pamela J Fraker,Louis E King

    Thymic atrophy, lymphopenia, and compromised cell- and antibody-mediated responses that cause increased rates of infections of longer duration are the immunological hallmarks of zinc deficiency (ZD) in humans and higher animals. As the deficiency advances, a reprogramming of the immune system occurs, beginning with the activation of the stress axis and chronic production of glucocorticoids that accelerate apoptosis among pre-B and -T cells. This reduces lymphopoiesis and causes atrophy of the thymus. In contrast, myelopoiesis is preserved, thereby providing protection for the first line of immune defense or innate immunity. Changes in gene expression for cytokines, DNA repair enzymes, zinc transporters, signaling molecules, etc., suggest that cells of the immune system are attempting to adapt to the stress of suboptimal zinc. Better understanding of the molecular and cellular changes made in response to inadequate zinc should lead to the development of immunotherapeutic interventions.

    更新日期:2019-11-01
  • Zinc and the risk for infectious disease.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2004-06-11
    Christa Fischer Walker,Robert E Black

    Zinc is an essential micronutrient for human growth, development, and immune function. Zinc deficiency impairs overall immune function and resistance to infection. Mild to moderate zinc deficiency can be best detected through a positive response to supplementation trials. Zinc supplementation has been shown to have a positive effect on the incidence of diarrhea (18% reduction, 95% CI: 7-28%) and pneumonia (41% reduction, 95% CI: 17-59%), and might lead to a decrease in the incidence of malaria. Zinc has also proven to decrease the duration of diarrhea by 15% (95% CI: 5-24%). Maternal zinc supplementation may lead to a decrease in infant infections. Studies assessing the role of zinc supplementation among persons with HIV, tuberculosis, and the common cold have not been conclusive. Two studies have shown zinc supplementation to decrease child mortality by more than 50%. Zinc clearly has an important role in infant and childhood infectious diseases; programs to increase the intake of zinc among deficient populations are needed.

    更新日期:2019-11-01
  • Nutrition and cancer prevention: a multidisciplinary perspective on human trials.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2004-06-11
    M R Forman,S D Hursting,A Umar,J C Barrett

    More than one million Americans were expected to be diagnosed with cancer in 2003 (7a). Compelling experimental, epidemiological, and clinical evidence indicates that many cancers are preventable, especially because diet and nutrition are key factors in the modulation of cancer risk. The road to nutritional intervention in cancer prevention has led to successful trials as well as trials that did not reach their intended endpoints. This chapter reviews four case studies of trials, with two ending in success and two ending in null findings or adverse effects. The goal is to identify lessons learned from all four case studies and from the investigations of the complexities inherent to nutritional intervention trials. Additional insights are presented by the research addressing potential mechanisms underlying the endpoints of human trials. Future progress in nutrition and cancer prevention will require expertise from multidisciplinary teams to develop new knowledge about specific nutrients and dietary modifications within a framework of interaction between animal and human research.

    更新日期:2019-11-01
  • Retinoic acid receptors and cancers.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2004-06-11
    Dianne Robert Soprano,Pu Qin,Kenneth J Soprano

    Studies utilizing experimental animals, epidemiological approaches, cellular models, and clinical trials all provide evidence that retinoic acid and some of its synthetic derivatives (retinoids) are useful pharmacological agents in cancer therapy and prevention. In this chapter, we first review the current knowledge of retinoic acid receptors (RARs) and their role in mediating the actions of retinoic acid. We then focus on a discussion of RARalpha and acute promyelocytic leukemia followed by a discussion of the role of RARs, in particular RARbeta expression, in other cancer types. Loss of normal RAR function in the presence of physiological levels of RA (either due to alterations in the protein structure or level of expression) is associated with a variety of different cancers. In some cases treatment with pharmacological doses of RA can be effective.

    更新日期:2019-11-01
  • Nutritional protection against skin damage from sunlight.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2004-06-11
    Helmut Sies,Wilhelm Stahl

    The concept of systemic photoprotection by dietary means is gaining momentum. Skin is continuously exposed to ultraviolet (UV) radiation, the major cause of skin disorders such as sunburn, photodamage, and nonmelanoma skin cancer. Most of the erythemal annual UV dose is encountered under nonvacation conditions, when no sunscreen is applied. In the absence of topically added compounds, skin protection depends solely on endogenous defense. Micronutrients can act as UV absorbers, as antioxidants, or can modulate signaling pathways elicited upon UV exposure. UV-induced erythema is a suitable parameter to assess photoprotection. Dietary protection is provided by carotenoids, tocopherols, ascorbate, flavonoids, or n-3 fatty acids, contributing to maintenance resistance as part of lifelong protection.

    更新日期:2019-11-01
  • Mammalian zinc transporters.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2004-06-11
    Juan P Liuzzi,Robert J Cousins

    New insights into mammalian zinc metabolism have been acquired through the identification and characterization of zinc transporters. These proteins all have transmembrane domains, and are encoded by two solute-linked carrier (SLC) gene families: ZnT (SLC30) and Zip (SLC39). There are at least 9 ZnT and 15 Zip transporters in human cells. They appear to have opposite roles in cellular zinc homeostasis. ZnT transporters reduce intracellular zinc availability by promoting zinc efflux from cells or into intracellular vesicles, while Zip transporters increase intracellular zinc availability by promoting extracellular zinc uptake and, perhaps, vesicular zinc release into the cytoplasm. Both the ZnT and Zip transporter families exhibit unique tissue-specific expression, differential responsiveness to dietary zinc deficiency and excess, and differential responsiveness to physiologic stimuli via hormones and cytokines.

    更新日期:2019-11-01
  • The critical role of the melanocortin system in the control of energy balance.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2004-06-11
    Randy J Seeley,Deborah L Drazen,Deborah J Clegg

    Animals have developed highly adaptive and redundant mechanisms to maintain energy balance by matching caloric intake to caloric expenditure. Recent evidence has pointed to a variety of peripheral signals that inform specific central nervous system (CNS) circuits about the status of peripheral energy stores as critical to the maintenance of energy balance. A critical component of these CNS circuits is the melanocortin system. Regulation of signaling by melanocortin 3 and melanocortin 4 receptors in the CNS is controlled via neuronal cell bodies in the arcuate nucleus of the hypothalamus that synthesize melanocortin receptor agonists such as alpha-melanocyte-stimulating hormone (alpha-MSH) or antagonists such as agouti-related protein (AgRP). The activity of these two populations of neurons is reciprocally regulated by a number of peripheral and central systems that influence energy balance. Further, increased melanocortin signaling via pharmacological or genetic means in the CNS causes potent reductions in food intake and weight loss. Decreased melanocortin signaling via pharmacological or genetic means results in increased food intake and weight gain. Reviewed here is the wide range of evidence that points to the melanocortin system as a critical node in the diverse neurocircuitry that regulates food intake and body weight.

    更新日期:2019-11-01
  • New insights into erythropoiesis: the roles of folate, vitamin B12, and iron.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2004-06-11
    Mark J Koury,Prem Ponka

    Erythropoiesis is the process in which new erythrocytes are produced. These new erythrocytes replace the oldest erythrocytes (normally about one percent) that are phagocytosed and destroyed each day. Folate, vitamin B12, and iron have crucial roles in erythropoiesis. Erythroblasts require folate and vitamin B12 for proliferation during their differentiation. Deficiency of folate or vitamin B12 inhibits purine and thymidylate syntheses, impairs DNA synthesis, and causes erythroblast apoptosis, resulting in anemia from ineffective erythropoiesis. Erythroblasts require large amounts of iron for hemoglobin synthesis. Large amounts of iron are recycled daily with hemoglobin breakdown from destroyed old erythrocytes. Many recently identified proteins are involved in absorption, storage, and cellular export of nonheme iron and in erythroblast uptake and utilization of iron. Erythroblast heme levels regulate uptake of iron and globin synthesis such that iron deficiency causes anemia by retarded production rates with smaller, less hemoglobinized erythrocytes.

    更新日期:2019-11-01
  • Developmental aspects and factors influencing the synthesis and status of ascorbic Acid in the pig.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2004-06-11
    D C Mahan,S Ching,K Dabrowski

    Ascorbic acid synthesis in the pig occurs at mid-pregnancy, but activity of the enzyme l-gulono-gamma-lactone oxidase (GLO) declines thereafter during gestation and remains low when the pig nurses the sow. During late gestation the ascorbic acid concentration in the fetus increases, but serum and liver ascorbic acid concentration in the sow declines without affecting the dam's liver GLO activity. It is presumed that as gestation progresses an increased amount of maternal ascorbic acid is transferred to the fetus and to the mammary gland. Colostrum and milk are rich sources of the vitamin and supply the nursing pig with ascorbic acid. The available data suggest that high amounts of ascorbic acid appear to suppress liver GLO activity in the pig. Upon weaning, when exogenous vitamin C is generally not provided, liver GLO activity and serum ascorbic acid increases. During the initial periods postweaning, some reports have indicated growth benefits of supplemental vitamin C. Body tissues differ in their concentrations of ascorbic acid, but tissues of high metabolic need generally have greater concentrations. The corpus luteum in the female, the testis in the male, and the adrenal glands in all pigs contain greater concentrations of the vitamin. Knockout genes preventing ascorbic acid synthesis in pigs have demonstrated poor skeletal and collagen formation and poor antioxidant protection. Under periods of stress ascorbic acid declines in the adrenal, but the pig rapidly recovers to its resting state once the stressor agent is removed. Although there are periods when supplemental vitamin C has been shown to promote pig performance (e.g., during high environmental stress and early postweaning), supplemental vitamin C has not been shown to routinely enhance pig performance.

    更新日期:2019-11-01
  • Molecular aspects of alcohol metabolism: transcription factors involved in early ethanol-induced liver injury.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2004-06-11
    Laura E Nagy

    Alcohol metabolism takes place primarily in the liver. Initial exposures to ethanol have a major impact on the hepatic redox state and intermediary metabolism as a consequence of ethanol metabolism via alcohol dehydrogenase. However, upon continued exposure to ethanol, the progression of liver injury involves ethanol metabolism via CYP2E1 and consequent oxidant stress, as well as potential direct effects of ethanol on membrane proteins that are independent of ethanol metabolism. Multiple organ systems contribute to liver injury, including the innate immune system and adipose tissue. In response to ethanol exposure, specific signal transduction pathways, including NFkappaB and the mitogen-activated protein kinase family members ERK1/2, JNK, and p38, are activated. These complex responses to ethanol exposure translate into activation of nuclear transcription factors and altered gene expression within the liver, leading to the development of steatosis and inflammation in the early stages of alcohol-induced liver injury.

    更新日期:2019-11-01
  • Isoflavones in soy infant formula: a review of evidence for endocrine and other activity in infants.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2004-06-11
    Aimin Chen,Walter J Rogan

    Soy infant formulas are widely used, but few studies have evaluated long-term safety or examined specific forms of toxicity, such as to the endocrine or immune systems. This review focuses on newer experimental studies of the effects on estrogen activity, immune function, and thyroid economy of genistein and daidzein, two isoflavones in soy infant formula, and existing human studies of soy formula use. In order to judge the likelihood that an endpoint seen in laboratory studies might occur in soy-fed infants, we examined the doses and the resulting serum or plasma concentrations from the laboratory studies and compared them with doses and concentrations seen in soy-fed infants. We also summarized the estimates of the potency of the isoflavone compounds relative to estradiol. Given the scarcity and inconsistency of existing human data and the substantial laboratory evidence of hormonal and other activity at doses relevant to the soy-fed infant, we conclude that more clinical and epidemiological study is warranted.

    更新日期:2019-11-01
  • Calcium and bone mineral metabolism in children with chronic illnesses.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2004-06-11
    S A Abrams,K O O'Brien

    Increased longevity and improved medical management of children with chronic illnesses has led to a focus on the short- and long-term consequences of these conditions on bone health. Bone loss is influenced by diet, malabsorption, and disease-related imbalances in bone turnover. It may be exacerbated by common medications, especially corticosteroids. Assessment of bone mass and quality, calcium absorption, kinetically derived rates of bone turnover, and biochemical markers of bone turnover have increased our knowledge of the pathophysiology of bone loss in these children as well as provided insights into possible therapeutic interventions. Increased intake of calcium and vitamin D, while useful, is unlikely to prevent or resolve bone loss in many chronically ill children. Emphasis on combination of nutritional interventions with exercise and newer bone-sparing therapies may be necessary.

    更新日期:2019-11-01
  • On becoming a nutritional biochemist.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2004-06-11
    Donald B McCormick

    Much of the science underlying nutrition has come from biochemical studies. This certainly is true in our understanding of the metabolism and function of such micronutrient cofactors as vitamins and metal ions. My own interest stems from an early desire to understand the molecular events in an organism and ultimately to know the fate of those nutrients that are needed to maintain life. My training in chemistry, biochemistry, and nutrition was helpful in gaining knowledge about the interface among these disciplines. My interests followed an understandable trail, beginning with those factors that cause plant galls and continuing through carbohydrate metabolism to vitamins. After all, from studying such pentitols as ribitol with Professor Touster at Vanderbilt University through indoctrination with enzymes, vitamins, and coenzymes with Professor Snell at the University of California-Berkeley, it was rational to begin my independent academic life investigating the enzymes that convert a ribityl-containing vitamin, namely riboflavin, to its operational flavocoenzymes. While at Cornell University, I encountered Professor Wright, who shared an interest in biotin. My realization that there was a similar need to determine the metabolism of lipoate followed logically. Interactions with inorganic chemists such as Professor Sigel at Basel University, as well as inorganic chemists at Cornell, led to an interest in metal ions. As summarized in this article, my colleagues and I are pleased to have contributed to both basic knowledge about cofactors and to have utilized much of this information in extensions to applications. Along the way, I have served by teaching, researching, and administrating at the universities that provided my positions in academe, and I have worked to share the load of numerous public and professional duties that are summarized herein. Altogether it has been an enjoyable career to be a nutritional biochemist. I recommend it for those who follow.

    更新日期:2019-11-01
  • Nutrition in the perioperative patient.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2003-10-07
    Lyn Howard,Christopher Ashley

    The association of malnutrition with surgical morbidity and mortality is well recognized. The question of whether this relationship is causal or simply an association in sick patients has been hotly debated. The field of nutrition support has grown out of the belief that correcting malnutrition will modify associated risks for poor outcome. It has been easier to substantiate this belief in some clinical situations than in others. The evidence for nutrition support during the perioperative period is reviewed and recommendations are made about where nutrition support is most useful and where it may be counterproductive. Some of the important unanswered questions about perioperative nutrition support are raised.

    更新日期:2019-11-01
  • Common endocrine control of body weight, reproduction, and bone mass.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2003-05-06
    Shu Takeda,Florent Elefteriou,Gerard Karsenty

    Bone mass is maintained constant between puberty and menopause by the balance between osteoblast and osteoclast activity. The existence of a hormonal control of osteoblast activity has been speculated for years by analogy to osteoclast biology. Through the search for such humoral signal(s) regulating bone formation, leptin has been identified as a strong inhibitor of bone formation. Furthermore, intracerebroventricular infusion of leptin has shown that the effect of this adipocyte-derived hormone on bone is mediated via a brain relay. Subsequent studies have led to the identification of hypothalamic groups of neurons involved in leptin's antiosteogenic function. In addition, those neurons or neuronal pathways are distinct from neurons responsible for the regulation of energy metabolism. Finally, the peripheral mediator of leptin's antiosteogenic function has been identified as the sympathetic nervous system. Sympathomimetics administered to mice decreased bone formation and bone mass. Conversely, beta-blockers increased bone formation and bone mass and blunted the bone loss induced by ovariectomy.

    更新日期:2019-11-01
  • Iron status and neural functioning.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2003-04-22
    John L Beard,James R Connor

    Iron deficiency in early life is associated with delayed development as assessed by a number of clinical trials using similar global scales of development; this poor development during infancy persists in most cases after iron therapy has corrected iron status. If iron deficiency occurs in preschool and older children, the consequences appear reversible with treatment. The biologic understanding of this relationship between development, brain iron status, and functioning is sparse though animal studies repeatedly demonstrate alterations in dopamine metabolism and in the myelination process. Dietary iron deficiency can rapidly deplete brain iron concentrations and repletion is able to normalize them. Residual alterations in striatal dopamine metabolism and myelin production persist if neonatal animals are used. Future studies with more specific measures of neurodevelopment in iron-deficient human infants, and animal models, will allow investigators to more clearly define causal roles of brain iron in neural development and functioning.

    更新日期:2019-11-01
  • Insights into the pathogenesis of galactosemia.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2003-04-22
    Nancy D Leslie

    In humans, the absence of galactose-1-phosphate uridyltransferase (GALT) leads to significant neonatal morbidity and mortality which are dependent on galactose ingestion, as well as long-term complications of primary ovarian failure and cognitive dysfunction, which are diet independent. The creation of a knockout mouse model for GALT deficiency was aimed at providing an organism in which metabolic challenges and gene manipulation could address the enigmatic pathophysiologic questions raised by humans with galactosemia. Instead, the mouse represents a biochemical phenotype without evidence of clinical morbidity. The similarities and differences between mice and humans with galactosemia are explored from metabolite, enzyme, and process points of view. The mouse both produces and oxidizes galactose in a manner similar to humans. It differs in brain accumulation of galactitol. Future directions for exploration of this enigmatic condition are discussed.

    更新日期:2019-11-01
  • In vivo measurement of fluxes through metabolic pathways: the missing link in functional genomics and pharmaceutical research.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2003-04-22
    Marc K Hellerstein

    In the postgenomic era of biology, much attention has been given to functional genomics, or the relation between genes and higher levels of organization in the cell. The latter are typically represented as mRNA, protein, or organic metabolite complements. The theme of this review is that the operational unit of function in complex biological systems is more properly seen as the fully assembled metabolic pathway in the whole organism. Due to the connectivity, interactions, and complexity of metabolic pathways, the measurement of components is an inadequate method for predicting phenotype. Measurement of the outputs of pathways (molecular fluxes) involves different tools than static measures of components, however. Here, we review recently developed stable isotope-mass spectrometric tools for measuring fluxes through metabolic pathways in vivo, focusing on the response to dietary macronutrients (carbohydrates and fats). Methods discussed include measurement of lipid dynamics, DNA replication, hepatic assembly of lipoproteins, and long-lived protein synthesis. Measuring fluxes through multiple pathways concurrently allows regulatory themes to emerge. Use of 2H2O-labeling is emerging as a particularly powerful approach for multiple concurrent biosynthetic flux measurements. Several examples demonstrate that pathway flux results are often unexpected and not predicted by classic biochemistry or the expression of genes and proteins.

    更新日期:2019-11-01
  • Dietary, evolutionary, and modernizing influences on the prevalence of type 2 diabetes.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2003-03-26
    Leslie Sue Lieberman

    An evolutionary perspective is used to elucidate the etiology of the current epidemic of type 2 diabetes estimated at 151 million people. Our primate legacy, fossil hominid, and hunting-gathering lifestyles selected for adaptive metabolically thrifty genotypes and phenotypes are rendered deleterious through modern lifestyles that increase energy input and reduce output. The processes of modernization or globalization include the availability and abundance of calorically dense/low-fiber/high-glycemic foods and the adoption of sedentary Western lifestyles, leading to obesity among both children and adults in developed and developing countries. These trends are projected to continue for a number of decades.

    更新日期:2019-11-01
  • Vitamin D and its analogs as regulators of immune activation and antigen presentation.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2003-03-26
    Matthew D Griffin,Nianzeng Xing,Rajiv Kumar

    It has been a little more than 20 years since the first appreciation that the biologically active hormonal form of the secosteroid vitamin D-classically categorized as a regulator of calcium/phosphorous metabolism and bone mineralization-can exert effects on cells of the immune system. Since then a substantial literature has accumulated to suggest that these effects are exerted on multiple immune cell types, are predominantly suppressive at pharmacologic levels, and are potent enough to have true therapeutic potential in the management or prevention of immune-mediated diseases. Less clear at present, however, are the physiological roles played by the vitamin D endocrine system in the regulation of normal and abnormal immune responses. In this review, an appraisal of the current understanding of vitamin D-mediated immune regulation is presented that emphasizes progress towards its clinical application as well as the manner in which emerging models of normal immune function may facilitate a more complete understanding of its physiologic significance.

    更新日期:2019-11-01
  • Diet and nutrition in poor and minority communities in the United States 100 years ago.
    Annu. Rev. Nutr. (IF 8.422) Pub Date : 2003-03-11
    Robert Dirks

    Atwater and his colleagues began studying food consumption in the closing years of the nineteenth century and from the very start devoted much effort to collecting data from poor and minority households. This paper reviews some of the fruits of these labors, particularly from the standpoint of what they contribute toward a better historical understanding of American food habits and nutrition. It surveys dietary data from African American, Appalachian white, Mexican American, native-born poor, and immigrant households. These data shed light on several areas of historical concern, including rural versus urban nutrition, seasonal hunger, class disparities, and food-habit change. I suggest the economically and culturally diverse sample of dietary patterns that comes to us as a legacy of the Atwater era sets the stage for a history of American food habits considerably more sophisticated than has been realized to date.

    更新日期:2019-11-01
Contents have been reproduced by permission of the publishers.
导出
全部期刊列表>>
2020新春特辑
限时免费阅读临床医学内容
ACS材料视界
科学报告最新纳米科学与技术研究
清华大学化学系段昊泓
自然科研论文编辑服务
加州大学洛杉矶分校
上海纽约大学William Glover
南开大学化学院周其林
课题组网站
X-MOL
北京大学分子工程苏南研究院
华东师范大学分子机器及功能材料
中山大学化学工程与技术学院
试剂库存
天合科研
down
wechat
bug