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Cogan B, Cooper JA. Differential effects of nutritive and non-nutritive sweet mouth rinsing on appetite in adults with obesity. Appetite 2024; 193:107133. [PMID: 38000768 DOI: 10.1016/j.appet.2023.107133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 10/09/2023] [Accepted: 11/19/2023] [Indexed: 11/26/2023]
Abstract
BACKGROUND Excessive added sugar intake has been associated with obesity; however, the effect of dietary sweetness on energy intake (EI) and appetite in adults with and without obesity has not yet been determined. OBJECTIVE To assess the effect of mouth rinses with and without energy and sweetness on measures of appetite, and to compare responses between subjects with body mass index (BMI) between 18.5 and 24.9 kg/m2 or ≥30 kg/m2. METHODS In this randomized, double-blind crossover study, 39 subjects (age 23±5y; 17 male, 22 female; BMI 18.5-24.9 kg/m2: n = 21; ≥30 kg/m2: n = 18) performed modified sham-feeding (MSF) with a mouth rinse containing either sucrose, sucralose, maltodextrin, or water for 2min before expectorating the solution. Blood sampling and subjective appetite assessments occurred at baseline (-5) and 15, 30, 60, and 90min post-MSF. After, EI was assessed at a buffet meal and post-meal appetite ratings were assessed hourly for 3h. RESULTS Post-MSF ghrelin increased for water vs. maltodextrin (water: p = 0.03). Post-MSF cholecystokinin increased following maltodextrin-MSF (p = 0.03) and sucralose-MSF (p = 0.005) vs. sucrose for those with BMI:18.5-24.9 kg/m2 only. There was greater post-MSF desire to eat in response to water vs. sucrose (p = 0.03) and reduced fullness with sucralose for those with BMI≥30 vs. 18.5-24.9 kg/m2 (p < 0.001). There was no difference in EI at the buffet meal by mouth rinse (p = 0.98) or by BMI (p = 0.12). However, there was greater post-meal fullness following sucralose-MSF vs. water (p = 0.03) and sucrose (p = 0.004) for those with BMI≥30 vs. 18.5-24.9 kg/m2. CONCLUSION Sucralose rinsing led to greater cephalic phase CCK release in adults with a BMI:18.5-24.9 kg/m2 only; however, ghrelin responses to unsweetened rinses were energy-specific for all adults. As subsequent EI was unaffected, further investigation of cephalic phase appetite is warranted.
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Affiliation(s)
- Betsy Cogan
- Department of Nutritional Sciences, University of Georgia, Athens, GA, USA
| | - Jamie A Cooper
- Department of Kinesiology, University of Georgia, Athens, GA, USA.
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2
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Aukan MI, Coutinho S, Pedersen SA, Simpson MR, Martins C. Differences in gastrointestinal hormones and appetite ratings between individuals with and without obesity-A systematic review and meta-analysis. Obes Rev 2023; 24:e13531. [PMID: 36416279 PMCID: PMC10078575 DOI: 10.1111/obr.13531] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 08/26/2022] [Accepted: 10/27/2022] [Indexed: 11/24/2022]
Abstract
Determining if gastrointestinal (GI) hormone response to food intake differs between individuals with, and without, obesity may improve our understanding of obesity pathophysiology. A systematic review and meta-analysis of studies assessing the concentrations of GI hormones, as well as appetite ratings, following a test meal, in individuals with and without obesity was undertaken. Systematic searches were conducted in the databases MEDLINE, Embase, Cochrane Library, PsycINFO, Web of Science, and ClinicalTrials.gov. A total of 7514 unique articles were retrieved, 115 included in the systematic review, and 70 in the meta-analysis. The meta-analysis compared estimated standardized mean difference in GI hormones' concentration, as well as appetite ratings, between individuals with and without obesity. Basal and postprandial total ghrelin concentrations were lower in individuals with obesity compared with controls, and this was reflected by lower postprandial hunger ratings in the former. Individuals with obesity had a lower postprandial concentration of total peptide YY compared with controls, but no significant differences were found for glucagon-like peptide 1, cholecystokinin, or other appetite ratings. A large methodological and statistical heterogeneity among studies was found. More comprehensive studies are needed to understand if the differences observed are a cause or a consequence of obesity.
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Affiliation(s)
- Marthe Isaksen Aukan
- Obesity Research Group, Department of Clinical and Molecular Medicine, Faculty of Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.,Centre of Obesity and Innovation (ObeCe), Clinic of Surgery, St. Olav University Hospital, Trondheim, Norway
| | - Silvia Coutinho
- Obesity Research Group, Department of Clinical and Molecular Medicine, Faculty of Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.,Department of Public Health Nutrition at the Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo (UiO), Oslo, Norway
| | - Sindre Andre Pedersen
- Library Section for Research Support, Data and Analysis, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Melanie Rae Simpson
- Department of Public Health and Nursing, Norwegian University of Science and Technology, Trondheim, Norway.,Clinical Research Unit Central Norway, St. Olavs Hospital, Trondheim, Norway
| | - Catia Martins
- Obesity Research Group, Department of Clinical and Molecular Medicine, Faculty of Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.,Centre of Obesity and Innovation (ObeCe), Clinic of Surgery, St. Olav University Hospital, Trondheim, Norway.,Department of Nutrition Sciences, the University of Alabama at Birmingham (UAB), Birmingham, Alabama, USA
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3
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Macronutrient Sensing in the Oral Cavity and Gastrointestinal Tract: Alimentary Tastes. Nutrients 2021; 13:nu13020667. [PMID: 33669584 PMCID: PMC7922037 DOI: 10.3390/nu13020667] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 02/09/2021] [Accepted: 02/16/2021] [Indexed: 02/07/2023] Open
Abstract
There are numerous and diverse factors enabling the overconsumption of foods, with the sense of taste being one of these factors. There are four well established basic tastes: sweet, sour, salty, and bitter; all with perceptual independence, salience, and hedonic responses to encourage or discourage consumption. More recently, additional tastes have been added to the basic taste list including umami and fat, but they lack the perceptual independence and salience of the basics. There is also emerging evidence of taste responses to kokumi and carbohydrate. One interesting aspect is the link with the new and emerging tastes to macronutrients, with each macronutrient having two distinct perceptual qualities that, perhaps in combination, provide a holistic perception for each macronutrient: fat has fat taste and mouthfeel; protein has umami and kokumi; carbohydrate has sweet and carbohydrate tastes. These new tastes can be sensed in the oral cavity, but they have more influence post- than pre-ingestion. Umami, fat, kokumi, and carbohydrate tastes have been suggested as an independent category named alimentary. This narrative review will present and discuss evidence for macronutrient sensing throughout the alimentary canal and evidence of how each of the alimentary tastes may influence the consumption of foods.
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4
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Costanzo A, Russell CG, Lewin S, Keast R. A Fatty Acid Mouth Rinse Decreases Self-Reported Hunger and Increases Self-Reported Fullness in Healthy Australian Adults: A Randomized Cross-Over Trial. Nutrients 2020; 12:nu12030678. [PMID: 32131518 PMCID: PMC7146224 DOI: 10.3390/nu12030678] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 02/27/2020] [Accepted: 02/28/2020] [Indexed: 12/21/2022] Open
Abstract
Fatty acid (FA) chemoreception in the oral cavity, known as fat taste, may trigger a satiety response that is homologous to FA chemoreception in the gastrointestinal tract. In addition, individuals with an impaired fat taste sensitivity are more likely to have an impaired satiety response. This study aimed to assess the effect of an FA mouth rinse on self-reported appetite, and to determine if the effect is modified by fat taste sensitivity. Thirty-one participants (age, 32.0 ± 8.4 y; body mass index (BMI), 26.1 ± 8.1 kg/m2) were studied on four separate days to evaluate the effect of a 20 mM oleic acid (OA) mouth rinse (in duplicate) compared to a control (in duplicate) on self-reported appetite by using a visual analogue scale (VAS) every 30 min for three hours following a standardized low-fat breakfast. The area under the curve ratings for fullness were greater (p = 0.003), and those for hunger were lower (p = 0.002) following the OA rinse compared to the control. The effect of the OA rinse was greater in individuals who were hypersensitive to fat taste compared to moderately sensitive and hyposensitive individuals for fullness (p < 0.010) and hunger (p < 0.010) ratings. In summary, an OA mouth rinse decreases self-reported hunger and increases self-reported fullness, particularly in those who are more sensitive to fat taste. FA receptors in the oral cavity may be potential targets to regulate appetite.
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5
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Al-Najim W, Docherty NG, le Roux CW. Food Intake and Eating Behavior After Bariatric Surgery. Physiol Rev 2018; 98:1113-1141. [PMID: 29717927 DOI: 10.1152/physrev.00021.2017] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Obesity is an escalating global chronic disease. Bariatric surgery is a very efficacious treatment for obesity and its comorbidities. Alterations to gastrointestinal anatomy during bariatric surgery result in neurological and physiological changes affecting hypothalamic signaling, gut hormones, bile acids, and gut microbiota, which coalesce to exert a profound influence on eating behavior. A thorough understanding of the mechanisms underlying eating behavior is essential in the management of patients after bariatric surgery. Studies investigating candidate mechanisms have expanded dramatically in the last decade. Herein we review the proposed mechanisms governing changes in eating behavior, food intake, and body weight after bariatric surgery. Additive or synergistic effects of both conditioned and unconditioned factors likely account for the complete picture of changes in eating behavior. Considered application of strategies designed to support the underlying principles governing changes in eating behavior holds promise as a means of optimizing responses to surgery and long-term outcomes.
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Affiliation(s)
- Werd Al-Najim
- Diabetes Complications Research Centre, Conway Institute, School of Medicine and Medical Sciences, University College Dublin , Dublin , Ireland ; Department of Gastrosurgical Research and Education, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg , Gothenburg , Sweden ; and Investigative Science, Imperial College London , London , United Kingdom
| | - Neil G Docherty
- Diabetes Complications Research Centre, Conway Institute, School of Medicine and Medical Sciences, University College Dublin , Dublin , Ireland ; Department of Gastrosurgical Research and Education, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg , Gothenburg , Sweden ; and Investigative Science, Imperial College London , London , United Kingdom
| | - Carel W le Roux
- Diabetes Complications Research Centre, Conway Institute, School of Medicine and Medical Sciences, University College Dublin , Dublin , Ireland ; Department of Gastrosurgical Research and Education, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg , Gothenburg , Sweden ; and Investigative Science, Imperial College London , London , United Kingdom
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6
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Dhillon J, Lee JY, Mattes RD. The cephalic phase insulin response to nutritive and low-calorie sweeteners in solid and beverage form. Physiol Behav 2017; 181:100-109. [PMID: 28899680 PMCID: PMC5634742 DOI: 10.1016/j.physbeh.2017.09.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 09/08/2017] [Accepted: 09/08/2017] [Indexed: 12/22/2022]
Abstract
The purpose of the study was to examine the role of the cephalic phase insulin response (CPIR) following exposure to nutritive and low-calorie sweeteners in solid and beverage form in overweight and obese adults. In addition, the role of learning on the CPIR to nutritive and low-calorie sweetener exposure was tested. Sixty-four overweight and obese adults (age: 18-50years, BMI: 24-37kg/m2, body fat percentage>25% for men and >32% for women) were sham-fed (at 2-minute intervals for 14min) a randomly assigned test load comprised of a nutritive (sucrose) or low-calorie sweetener (sucralose) in beverage or solid form in phase 1 of the study. A 2-3ml blood sample was collected before and 2, 6, 10, 14, 61, 91 and 121min after oral exposure for serum insulin and glucose analysis. During phase 2, participants underwent a 2-week training period to facilitate associative learning between the sensory properties of test loads and their post-ingestive effects. In phase 3, participants were retested for their cephalic phase responses as in phase 1. Participants were classified as responders if they demonstrated a positive insulin response (rise of serum insulin above baseline i.e. Δ insulin) 2min post-stimulus in phase 1. Among responders exposed to the same sweetener in Phases 1 and 3, the proportion of participants that displayed a rise of insulin with oral exposure to sucralose was significantly greater when the stimulus was in the solid form compared to the beverage form. Sucralose and sucrose exposure elicited similarly significant increases in serum insulin 2min after exposure and significant decreases after 2min in responders in both food forms. The solid food form elicited greater CPIR over 2, 6 and 10min than the beverage form. There was no effect of learning on insulin responses after training. The results indicate the presence of a significant CPIR in a subset of individuals with overweight or obesity after oral exposure to sucralose, especially when present in solid food form. Future studies must confirm the reliability of this response.
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Affiliation(s)
- Jaapna Dhillon
- Department of Nutrition Science, Purdue University, 226 Stone Hall, 700 W State Street, West Lafayette 47907, IN, USA.
| | - Janice Y Lee
- Department of Nutrition Science, Purdue University, 226 Stone Hall, 700 W State Street, West Lafayette 47907, IN, USA.
| | - Richard D Mattes
- Department of Nutrition Science, Purdue University, 226 Stone Hall, 700 W State Street, West Lafayette 47907, IN, USA.
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7
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A Review of the Evidence Supporting the Taste of Non‐esterified Fatty Acids in Humans. J AM OIL CHEM SOC 2016. [DOI: 10.1007/s11746-016-2885-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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8
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Carreiro AL, Dhillon J, Gordon S, Jacobs AG, Higgins KA, McArthur BM, Redan BW, Rivera RL, Schmidt LR, Mattes RD. The Macronutrients, Appetite, and Energy Intake. Annu Rev Nutr 2016; 36:73-103. [PMID: 27431364 PMCID: PMC4960974 DOI: 10.1146/annurev-nutr-121415-112624] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Each of the macronutrients-carbohydrate, protein, and fat-has a unique set of properties that influences health, but all are a source of energy. The optimal balance of their contribution to the diet has been a long-standing matter of debate. Over the past half century, thinking has progressed regarding the mechanisms by which each macronutrient may contribute to energy balance. At the beginning of this period, metabolic signals that initiated eating events (i.e., determined eating frequency) were emphasized. This was followed by an orientation to gut endocrine signals that purportedly modulate the size of eating events (i.e., determined portion size). Most recently, research attention has been directed to the brain, where the reward signals elicited by the macronutrients are viewed as potentially problematic (e.g., contribute to disordered eating). At this point, the predictive power of the macronutrients for energy intake remains limited.
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Affiliation(s)
- Alicia L Carreiro
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907
| | - Jaapna Dhillon
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907
| | - Susannah Gordon
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907
| | - Ashley G Jacobs
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907
| | - Kelly A Higgins
- Department of Food Science, Purdue University, West Lafayette, IN 47907
| | | | - Benjamin W Redan
- Department of Food Science, Purdue University, West Lafayette, IN 47907
| | - Rebecca L Rivera
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907
| | - Leigh R Schmidt
- Department of Food Science, Purdue University, West Lafayette, IN 47907
| | - Richard D Mattes
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907
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9
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Hsu TM, Suarez AN, Kanoski SE. Ghrelin: A link between memory and ingestive behavior. Physiol Behav 2016; 162:10-7. [PMID: 27072509 DOI: 10.1016/j.physbeh.2016.03.039] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 03/29/2016] [Accepted: 03/31/2016] [Indexed: 01/25/2023]
Abstract
Feeding is a highly complex behavior that is influenced by learned associations between external and internal cues. The type of excessive feeding behavior contributing to obesity onset and metabolic deficit may be based, in part, on conditioned appetitive and ingestive behaviors that occur in response to environmental and/or interoceptive cues associated with palatable food. Therefore, there is a critical need to understand the neurobiology underlying learned aspects of feeding behavior. The stomach-derived "hunger" hormone, ghrelin, stimulates appetite and food intake and may function as an important biological substrate linking mnemonic processes with feeding control. The current review highlights data supporting a role for ghrelin in mediating the cognitive and neurobiological mechanisms that underlie conditioned feeding behavior. We discuss the role of learning and memory on food intake control (with a particular focus on hippocampal-dependent memory processes) and provide an overview of conditioned cephalic endocrine responses. A neurobiological framework is provided through which conditioned cephalic ghrelin secretion signals in neurons in the hippocampus, which then engage orexigenic neural circuitry in the lateral hypothalamus to express learned feeding behavior.
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Affiliation(s)
- Ted M Hsu
- Human and Evolutionary Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA; Neuroscience Program, University of Southern California, Los Angeles, CA, USA
| | - Andrea N Suarez
- Human and Evolutionary Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Scott E Kanoski
- Human and Evolutionary Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA; Neuroscience Program, University of Southern California, Los Angeles, CA, USA.
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10
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Mishra AK, Dubey V, Ghosh AR. Obesity: An overview of possible role(s) of gut hormones, lipid sensing and gut microbiota. Metabolism 2016; 65:48-65. [PMID: 26683796 DOI: 10.1016/j.metabol.2015.10.008] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 08/31/2015] [Accepted: 10/01/2015] [Indexed: 12/15/2022]
Abstract
Obesity is one of the major challenges for public health in 21st century, with 1.9 billion people being considered as overweight and 600 million as obese. There are certain diseases such as type 2 diabetes, hypertension, cardiovascular disease, and several forms of cancer which were found to be associated with obesity. Therefore, understanding the key molecular mechanisms involved in the pathogenesis of obesity could be beneficial for the development of a therapeutic approach. Hormones such as ghrelin, glucagon like peptide 1 (GLP-1) peptide YY (PYY), pancreatic polypeptide (PP), cholecystokinin (CCK) secreted by an endocrine organ gut, have an intense impact on energy balance and maintenance of homeostasis by inducing satiety and meal termination. Glucose and energy homeostasis are also affected by lipid sensing in which different organs respond in different ways. However, there is one common mechanism i.e. formation of esterified lipids (long chain fatty acyl CoAs) and the activation of protein kinase C δ (PKC δ) involved in all these organs. The possible role of gut microbiota and obesity has been addressed by several researchers in recent years, indicating the possible therapeutic approach toward the management of obesity by the introduction of an external living system such as a probiotic. The proposed mechanism behind this activity is attributed by metabolites produced by gut microbial organisms. Thus, this review summarizes the role of various physiological factors such as gut hormone and lipid sensing involved in various tissues and organ and most important by the role of gut microbiota in weight management.
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Affiliation(s)
- Alok Kumar Mishra
- Centre for Infectious Diseases and Control, School of BioSciences and Technology, VIT University, Vellore, 632014, Tamil Nadu, India
| | - Vinay Dubey
- Centre for Infectious Diseases and Control, School of BioSciences and Technology, VIT University, Vellore, 632014, Tamil Nadu, India
| | - Asit Ranjan Ghosh
- Centre for Infectious Diseases and Control, School of BioSciences and Technology, VIT University, Vellore, 632014, Tamil Nadu, India.
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Abstract
Little is known about the effects of undernutrition on the specific muscles and neuronal circuits involved in mastication. The aim of this study was to document the effects of neonatal low-protein diet on masticatory efficiency. Newborn rats whose mothers were fed 17% (nourished (N), n 60) or 8% (undernourished (U), n 56) protein were compared. Their weight was monitored and their masticatory jaw movements were video-recorded. Whole-cell patch-clamp recordings were performed in brainstem slice preparations to investigate the intrinsic membrane properties and N-methyl-d-aspartate-induced bursting characteristics of the rhythmogenic neurons (N, n 43; U, n 39) within the trigeminal main sensory nucleus (NVsnpr). Morphometric analysis (N, n 4; U, n 5) were conducted on masseteric muscles serial cross-sections. Our results showed that undernourished animals had lower numbers of masticatory sequences (P=0·049) and cycles (P=0·045) and slower chewing frequencies (P=0·004) (N, n 32; U, n 28). Undernutrition reduced body weight but had little effect on many basic NVsnpr neuronal electrophysiological parameters. It did, however, affect sag potentials (P<0·001) and rebound firing (P=0·005) that influence firing pattern. Undernutrition delayed the appearance of bursting and reduced the propensity to burst (P=0·002), as well as the bursting frequency (P=0·032). Undernourished animals showed increased and reduced proportions of fibre type IIA (P<0·0001) and IIB (P<0·0001), respectively. In addition, their fibre areas (IIA, P<0·001; IIB, P<0·001) and perimeters (IIA, P<0·001; IIB, P<0·001) were smaller. The changes observed at the behavioural, neuronal and muscular levels suggest that undernutrition reduces chewing efficiency by slowing, weakening and delaying maturation of the masticatory muscles and the associated neuronal circuitry.
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Camilleri M. Peripheral mechanisms in appetite regulation. Gastroenterology 2015; 148:1219-33. [PMID: 25241326 PMCID: PMC4369188 DOI: 10.1053/j.gastro.2014.09.016] [Citation(s) in RCA: 142] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 09/09/2014] [Accepted: 09/15/2014] [Indexed: 12/13/2022]
Abstract
Peripheral mechanisms in appetite regulation include the motor functions of the stomach, such as the rate of emptying and accommodation, which convey symptoms of satiation to the brain. The rich repertoire of peripherally released peptides and hormones provides feedback from the arrival of nutrients in different regions of the gut from where they are released to exert effects on satiation, or regulate metabolism through their incretin effects. Ultimately, these peripheral factors provide input to the highly organized hypothalamic circuitry and vagal complex of nuclei to determine cessation of energy intake during meal ingestion, and the return of appetite and hunger after fasting. Understanding these mechanisms is key to the physiological control of feeding and the derangements that occur in obesity and their restoration with treatment (as shown by the effects of bariatric surgery).
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Affiliation(s)
- Michael Camilleri
- Clinical Enteric Neuroscience Translational and Epidemiological Research, Mayo Clinic College of Medicine, Rochester, Minnesota.
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13
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Keast RSJ, Costanzo A. Is fat the sixth taste primary? Evidence and implications. ACTA ACUST UNITED AC 2015. [DOI: 10.1186/2044-7248-4-5] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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14
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Zhu Y, Hsu WH, Hollis JH. Modified sham feeding of foods with different macronutrient compositions differentially influences cephalic change of insulin, ghrelin, and NMR-based metabolomic profiles. Physiol Behav 2014; 135:135-42. [DOI: 10.1016/j.physbeh.2014.06.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 06/10/2014] [Accepted: 06/11/2014] [Indexed: 12/25/2022]
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15
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Tucker RM, Mattes RD, Running CA. Mechanisms and effects of "fat taste" in humans. Biofactors 2014; 40:313-26. [PMID: 24591077 DOI: 10.1002/biof.1162] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 02/18/2014] [Indexed: 12/11/2022]
Abstract
Evidence supporting a "taste" cue from fat in the oral cavity continues to accrue. The proposed stimuli for fat taste, non-esterified fatty acids (NEFA), are released from food through hydrolytic rancidity and lipase activity derived from foods or saliva. NEFA must then be released from the food matrix, negotiate the aqueous environment to reach taste cell surfaces, and interact with receptors such as CD36 and GPR120 or diffuse across cell membranes to initiate a taste signal. Knowledge of these processes in non-gustatory tissues should inform understanding of taste responses to NEFA. Additionally, downstream effects of oral triglyceride exposure have been observed in numerous studies. Data specific to effects of NEFA versus triglyceride are scarce, but modified sham feeding trials with triglyceride document cephalic phase responses including elevations in serum lipids and insulin as well as potential, but debated, effects on gut peptides, appetite, and thermogenesis. In this review, we highlight the mechanisms by which NEFA migrate to and interact with taste cells, and then we examine physiological responses to oral fat exposure.
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Affiliation(s)
- Robin M Tucker
- Department of Nutrition Science, Purdue University, West Lafayette, IN, USA
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16
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Duca FA, Sakar Y, Covasa M. The modulatory role of high fat feeding on gastrointestinal signals in obesity. J Nutr Biochem 2014; 24:1663-77. [PMID: 24041374 DOI: 10.1016/j.jnutbio.2013.05.005] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 05/13/2013] [Accepted: 05/28/2013] [Indexed: 01/03/2023]
Abstract
The gastrointestinal (GI) tract is a specialized sensory system that detects and responds to constant changes in nutrient- and bacterial-derived intestinal signals, thus contributing to controls of food intake. Chronic exposure to dietary fat causes morphological, physiological and metabolic changes leading to disruptions in the regulatory feeding pathways promoting more efficient fat absorption and utilization, blunted satiation signals and excess adiposity. Accumulating evidence demonstrates that impaired gastrointestinal signals following long-term high fat consumption are, at least partially, responsible for increased caloric intake. This review focuses on the role of dietary fat in modulating oral and post-oral chemosensory signaling elements responsible for lipid detection and responses, including changes in sensitivity to satiation signals, such as GLP-1, PYY and CCK and their impact on food intake and weight gain. Furthermore, the influence of the gut microbiota on mechanisms controlling energy regulation in the face of excessive fat exposure will be explored. The profound influence of dietary fats on altering complex regulatory feeding pathways can result in dysregulation of body weight and development of obesity, while restoration or manipulation of satiation signaling may prove an effective tool in prevention and treatment of obesity.
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Affiliation(s)
- Frank A Duca
- INRA, UMR 1319 Micalis, F-78352 Jouy-en-Josas, France; AgroParis Tech, UMR 1319, F-78352 Jouy-en-Josas, France; University Pierre and Marie Curie, 75006 Paris, France
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Chewing thoroughly reduces eating rate and postprandial food palatability but does not influence meal size in older adults. Physiol Behav 2014; 123:62-6. [DOI: 10.1016/j.physbeh.2013.10.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2013] [Revised: 09/25/2013] [Accepted: 10/07/2013] [Indexed: 01/22/2023]
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Mathus-Vliegen EMH, de Groot GH. Fasting and meal-induced CCK and PP secretion following intragastric balloon treatment for obesity. Obes Surg 2013; 23:622-33. [PMID: 23224567 DOI: 10.1007/s11695-012-0834-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Satiety is centrally and peripherally mediated by gastrointestinal peptides and the vagal nerve. We aimed to investigate whether intragastric balloon treatment affects satiety through effects on fasting and meal-stimulated cholecystokinin (CCK) and pancreatic polypeptide (PP) secretion. METHODS Patients referred for obesity treatment were randomised to 13 weeks of sham treatment followed by 13 weeks of balloon treatment (group 1; sham/balloon) or to twice a 13-week period of balloon treatment (group 2; balloon/balloon). Blood samples were taken for fasting and meal-stimulated CCK and PP levels at the start (T0) and after 13 (T1) and 26 (T2) weeks. Patients filled out visual analogue scales (VAS) to assess satiety. RESULTS Forty-two patients (35 females, body weight 125.1 kg, BMI 43.3 kg/m(2)) participated. In group 1, basal CCK levels decreased but meal-stimulated response remained unchanged after 13 weeks of sham treatment. In group 2, basal and meal-stimulated CCK levels decreased after 13 weeks of balloon treatment. At the end of the second 13-week period, when group 1 had their first balloon treatment, they duplicated the initial 13-week results of group 2, whereas group 2 continued their balloon treatment and reduced meal-stimulated CCK release. Both groups showed reduced meal-stimulated PP secretions at T1 and T2 compared to T0. Changes in diet composition and VAS scores were similar. Improvements in glucose homeostasis partly explained the PP results. CONCLUSIONS The reduced CCK and PP secretion after balloon positioning was unexpected and may reflect delayed gastric emptying induced by the balloon. Improved glucose metabolism partly explained the reduced PP secretion. Satiety and weight loss were not adversely influenced by these hormonal changes.
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Affiliation(s)
- Elisabeth M H Mathus-Vliegen
- Department of Gastroenterology and Hepatology, Academic Medical Centre, University of Amsterdam, Meibergdreef 9, 1105, AZ, Amsterdam, the Netherlands.
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Alterations in gut hormones after laparoscopic sleeve gastrectomy: a prospective clinical and laboratory investigational study. Ann Surg 2013; 257:647-54. [PMID: 23108120 DOI: 10.1097/sla.0b013e31826e1846] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE To evaluate the effect of laparoscopic sleeve gastrectomy (LSG) on fasting and meal-stimulated release of the gut hormones ghrelin, pancreatic polypeptide (PP), peptide-YY (PYY), glucagon-like peptide-1 (GLP-1), and amylin and of the adipocytokine leptin. BACKGROUND Mounting evidence suggests that the mechanisms of weight loss and the improvement in glucose metabolism seen after LSG are related not only to gastric restriction but also to neurohormonal changes. METHODS : Fasting and postprandial levels at 60 and 120 minutes after a standard test meal of the above peptides and glucose metabolism indices were evaluated in 15 consecutive morbidly obese (MO) subjects before and 6 and 12 months after LSG. As study controls, 15 lean subjects matched for age and sex were also assessed. RESULTS Body mass index values notably decreased at 6 and 12 months (P < 0.01), postoperatively. In addition, an overall improvement of the glycemic profile of MO patients was noted. After LSG, markedly decreased fasting and postprandial levels of ghrelin, amylin, and leptin were observed. A significant postprandial increase of PYY and GLP-1 levels was also noted postoperatively. Interestingly, significantly increased levels of PP were noted only at 60 minutes postprandially after LSG. CONCLUSIONS LSG markedly improved glucose homeostasis and generated significant changes in ghrelin, PP, PYY, GLP-1, amylin, and leptin levels. These multiple hormonal actions may have several beneficial effects on the underlying mechanism of weight loss, demonstrating that LSG could be more than just a restrictive bariatric operation.
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Increasing the number of masticatory cycles is associated with reduced appetite and altered postprandial plasma concentrations of gut hormones, insulin and glucose. Br J Nutr 2012. [PMID: 23181989 DOI: 10.1017/s0007114512005053] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
To determine the influence of masticatory efficiency on postprandial satiety and glycaemic response, twenty-one healthy males were recruited for this randomised cross-over trial. The participants consumed a fixed amount of pizza provided in equal-sized portions by chewing each portion either fifteen or forty times before swallowing. Subjective appetite was measured by appetite questionnaires at regular intervals for 3 h after the meal and plasma samples were collected for the measurement of selected satiety-related hormones, glucose, insulin and glucose-dependent insulinotropic peptide (GIP) concentrations. An ad libitum meal was provided shortly after the last blood sample was drawn and the amount eaten recorded. Compared with fifteen chews, chewing forty times per portion resulted in lower hunger (P= 0·009), preoccupation with food (P= 0·005) and desire to eat (P= 0·002). Meanwhile, plasma concentrations of glucose (P= 0·024), insulin (P< 0·001) and GIP (P< 0·001) were higher following the forty-chews meal. Chewing forty times before swallowing also resulted in a higher plasma cholecystokinin concentration (P= 0·045) and a trend towards a lower ghrelin concentration (P= 0·051). However, food intake at the subsequent test meal did not differ (P= 0·851). The results suggest that a higher number of masticatory cycles before swallowing may provide beneficial effects on satiety and facilitate glucose absorption.
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Abstract
The sensory properties of foods and beverages are primary determinants of food choice. Some flavor components have an inherent hedonic valence that influences ingestive behavior. However, these hedonic impressions may be modified and others newly formed through their association with the post-ingestive consequences of food and beverage consumption. Flavor-active compounds, including spices, also modify digestive, absorptive and metabolic processes through direct activation of signaling pathways or via neurally-mediated cephalic phase responses. These may modify energy balance through effects on food digestion, energy absorption and metabolism. Thus, collectively, flavor has the potential to modify energy balance. Attempts to purposefully augment energy and nutrient intake have largely focused on the aging population where flavor fortification is posited to correct for diminishing sensory function. Evidence of efficacy is not strong, possibly due to methodological issues such as low statistical power and failure to match documented sensory limitations with the nature of the intervention. More rigorous testing should determine the viability of this therapeutic application of food flavors. The use of flavor compounds for weight reduction has yielded mixed results. Most trials have delivered the compounds via capsule precluding assessment of flavor to outcomes. Work with red pepper suggests there is an independent, albeit subtle, sensory effect on substrate oxidation coupled with a more general reduction of appetite and enhancement of energy expenditure. Flavor active compounds hold some promise for being more a part of the solution than the problem of disordered eating and unhealthy weight.
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Affiliation(s)
- Richard D Mattes
- Purdue University, Department of Nutrition Science, Stone Hall, Rm. 212, 700 West State Street, West Lafayette, IN 47907-2059, USA.
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Suzuki K, Jayasena CN, Bloom SR. Obesity and appetite control. EXPERIMENTAL DIABETES RESEARCH 2012; 2012:824305. [PMID: 22899902 PMCID: PMC3415214 DOI: 10.1155/2012/824305] [Citation(s) in RCA: 123] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 06/20/2012] [Indexed: 01/01/2023]
Abstract
Obesity is one of the major challenges to human health worldwide; however, there are currently no effective pharmacological interventions for obesity. Recent studies have improved our understanding of energy homeostasis by identifying sophisticated neurohumoral networks which convey signals between the brain and gut in order to control food intake. The hypothalamus is a key region which possesses reciprocal connections between the higher cortical centres such as reward-related limbic pathways, and the brainstem. Furthermore, the hypothalamus integrates a number of peripheral signals which modulate food intake and energy expenditure. Gut hormones, such as peptide YY, pancreatic polypeptide, glucagon-like peptide-1, oxyntomodulin, and ghrelin, are modulated by acute food ingestion. In contrast, adiposity signals such as leptin and insulin are implicated in both short- and long-term energy homeostasis. In this paper, we focus on the role of gut hormones and their related neuronal networks (the gut-brain axis) in appetite control, and their potentials as novel therapies for obesity.
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Affiliation(s)
- Keisuke Suzuki
- Section of Investigative Medicine, Imperial College London, Commonwealth Building, Du Cane Road, London W12 0NN, UK
| | - Channa N. Jayasena
- Section of Investigative Medicine, Imperial College London, Commonwealth Building, Du Cane Road, London W12 0NN, UK
| | - Stephen R. Bloom
- Section of Investigative Medicine, Imperial College London, Commonwealth Building, Du Cane Road, London W12 0NN, UK
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Abstract
Obesity is one of the major challenges to human health worldwide; however, there are currently no effective pharmacological interventions for obesity. Recent studies have improved our understanding of energy homeostasis by identifying sophisticated neurohumoral networks which convey signals between the brain and gut in order to control food intake. The hypothalamus is a key region which possesses reciprocal connections between the higher cortical centres such as reward-related limbic pathways, and the brainstem. Furthermore, the hypothalamus integrates a number of peripheral signals which modulate food intake and energy expenditure. Gut hormones, such as peptide YY, pancreatic polypeptide, glucagon-like peptide-1, oxyntomodulin, and ghrelin, are modulated by acute food ingestion. In contrast, adiposity signals such as leptin and insulin are implicated in both short- and long-term energy homeostasis. In this paper, we focus on the role of gut hormones and their related neuronal networks (the gut-brain axis) in appetite control, and their potentials as novel therapies for obesity.
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Cardona Cano S, Merkestein M, Skibicka KP, Dickson SL, Adan RAH. Role of ghrelin in the pathophysiology of eating disorders: implications for pharmacotherapy. CNS Drugs 2012; 26:281-96. [PMID: 22452525 DOI: 10.2165/11599890-000000000-00000] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Ghrelin is the only known circulating orexigenic hormone. It increases food intake by interacting with hypothalamic and brainstem circuits involved in energy balance, as well as reward-related brain areas. A heightened gut-brain ghrelin axis is an emerging feature of certain eating disorders such as anorexia nervosa and Prader-Willi syndrome. In common obesity, ghrelin levels are lowered, whereas post-meal ghrelin levels remain higher than in lean individuals. Agents that interfere with ghrelin signalling have therapeutic potential for eating disorders, including obesity. However, most of these drugs are only in the preclinical phase of development. Data obtained so far suggest that ghrelin agonists may have potential in the treatment of anorexia nervosa, while ghrelin antagonists seem promising for other eating disorders such as obesity and Prader-Willi syndrome. However, large clinical trials are needed to evaluate the efficacy and safety of these drugs.
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Suzuki K, Jayasena CN, Bloom SR. The gut hormones in appetite regulation. J Obes 2011; 2011:528401. [PMID: 21949903 PMCID: PMC3178198 DOI: 10.1155/2011/528401] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Accepted: 07/25/2011] [Indexed: 12/12/2022] Open
Abstract
Obesity has received much attention worldwide in association with an increased risk of cardiovascular diseases, diabetes, and cancer. At present, bariatric surgery is the only effective treatment for obesity in which long-term weight loss is achieved in patients. By contrast, pharmacological interventions for obesity are usually followed by weight regain. Although the exact mechanisms of long-term weight loss following bariatric surgery are yet to be fully elucidated, several gut hormones have been implicated. Gut hormones play a critical role in relaying signals of nutritional and energy status from the gut to the central nervous system, in order to regulate food intake. Cholecystokinin, peptide YY, pancreatic polypeptide, glucagon-like peptide-1, and oxyntomodulin act through distinct yet synergistic mechanisms to suppress appetite, whereas ghrelin stimulates food intake. Here, we discuss the role of gut hormones in the regulation of food intake and body weight.
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Affiliation(s)
- Keisuke Suzuki
- Section of Investigative Medicine, Imperial College London, London W12 0NN, UK
| | - Channa N. Jayasena
- Section of Investigative Medicine, Imperial College London, London W12 0NN, UK
| | - Stephen R. Bloom
- Section of Investigative Medicine, Imperial College London, London W12 0NN, UK
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Li J, Zhang N, Hu L, Li Z, Li R, Li C, Wang S. Improvement in chewing activity reduces energy intake in one meal and modulates plasma gut hormone concentrations in obese and lean young Chinese men. Am J Clin Nutr 2011; 94:709-16. [PMID: 21775556 DOI: 10.3945/ajcn.111.015164] [Citation(s) in RCA: 123] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Mastication is the first step in ingesting food, but the effects of mastication on energy intake and gut hormones in both obese and lean subjects have not been extensively evaluated. OBJECTIVE The current study aimed to compare the differences in chewing activities between obese and lean subjects and to examine the effects of chewing on energy intake and gut hormone concentrations in both obese and lean subjects. DESIGN Sixteen lean and 14 obese young men participated in the current research. In study 1, we investigated whether the chewing factors of obese subjects were different from those of lean subjects. In study 2, we explored the effects of chewing on energy intake. A test meal consisting of 2200 kJ (68% of energy as carbohydrate, 21% of energy as fat, and 11% of energy as protein) was then consumed on 2 different sessions (15 chews and 40 chews per bite of 10 g of food) by each subject to assess the effects of chewing on plasma gut hormone concentrations. RESULTS Compared with lean participants, obese participants had a higher ingestion rate and a lower number of chews per 1 g of food. However, obese participants had a bite size similar to that of lean subjects. Regardless of status, the subjects ingested 11.9% less after 40 chews than after 15 chews. Compared with 15 chews, 40 chews resulted in lower energy intake and postprandial ghrelin concentration and higher postprandial glucagon-like peptide 1 and cholecystokinin concentrations in both lean and obese subjects. CONCLUSION Interventions aimed at improving chewing activity could become a useful tool for combating obesity. This trial was registered at chictr.org as ChiCTR-OCC-10001181.
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Affiliation(s)
- Jie Li
- Department of Nutrition and Food Hygiene, School of Public Health, Harbin Medical University, China
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The neuropeptide Y system: Pathophysiological and therapeutic implications in obesity and cancer. Pharmacol Ther 2011; 131:91-113. [DOI: 10.1016/j.pharmthera.2011.03.011] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2011] [Accepted: 03/07/2011] [Indexed: 12/28/2022]
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Stewart JE, Feinle-Bisset C, Keast RSJ. Fatty acid detection during food consumption and digestion: Associations with ingestive behavior and obesity. Prog Lipid Res 2011; 50:225-33. [PMID: 21356242 DOI: 10.1016/j.plipres.2011.02.002] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Accepted: 02/22/2011] [Indexed: 12/28/2022]
Abstract
The inability of humans to adequately regulate fat consumption is a salient contributor to the development of obesity. The macronutrients, fat, protein and carbohydrate, within foods are detected at various stages of consumption, during which their digestive products, fatty acids, amino acids and sugars, interact with chemosensory cells within the oral epithelium (taste receptor cells) and gastrointestinal (GI) tract (enteroendocrine cells). This chemoreception initiates functional responses, including taste perception, peptide secretion and alterations in GI motility, that play an important role in liking of food, appetite regulation and satiety. This review will summarize the available evidence relating to the oral and GI regulation of fat intake and how chemoreception at both locations is associated with digestive behavior, satiety and weight regulation.
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Affiliation(s)
- Jessica E Stewart
- Centre for Physical Activity and Nutrition Research, Sensory Science Group, School of Exercise and Nutrition Sciences, Deakin University, Burwood, Victoria, Australia
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Oral fatty acid signaling and intestinal lipid processing: support and supposition. Physiol Behav 2011; 105:27-35. [PMID: 21324328 DOI: 10.1016/j.physbeh.2011.02.016] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2010] [Revised: 02/04/2011] [Accepted: 02/08/2011] [Indexed: 01/22/2023]
Abstract
There is increasing recognition that specialized processes once thought to be relatively isolated to the oral cavity (e.g., taste) and intestine (e.g., nutrient absorption) are better characterized as common and continuous. This is exemplified by accumulating evidence linking oral detection of dietary fats to their intestinal processing. This review first summarizes this literature focusing on purported gustatory signaling by free fatty acid stimulation and enterocyte lipid storage and mobilization in humans. It then willfully speculates on the possible functions of this integrated system. It is proposed that it may aid absorption of fat soluble nutrients, enhance acute energy intake, sustain intestinal function during long inter-meal intervals, modulate appetite and/or detoxify ingested compounds including free fatty acids.
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Suzuki K, Simpson KA, Minnion JS, Shillito JC, Bloom SR. The role of gut hormones and the hypothalamus in appetite regulation. Endocr J 2010; 57:359-72. [PMID: 20424341 DOI: 10.1507/endocrj.k10e-077] [Citation(s) in RCA: 186] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The World Health Organisation has estimated that by 2015 approximately 2.3 billion adults will be overweight and more than 700 million obese. Obesity is associated with an increased risk of diabetes, cardiovascular events, stroke and cancer. The hypothalamus is a crucial region for integrating signals from central and peripheral pathways and plays a major role in appetite regulation. In addition, there are reciprocal connections with the brainstem and higher cortical centres. In the arcuate nucleus of the hypothalamus, there are two major neuronal populations which stimulate or inhibit food intake and influence energy homeostasis. Within the brainstem, the dorsal vagal complex plays a role in the interpretation and relaying of peripheral signals. Gut hormones act peripherally to modulate digestion and absorption of nutrients. However, they also act as neurotransmitters within the central nervous system to control food intake. Peptide YY, pancreatic polypeptide, glucagon-like peptide-1 and oxyntomodulin suppress appetite, whilst ghrelin increases appetite through afferent vagal fibres to the caudal brainstem or directly to the hypothalamus. A better understanding of the role of these gut hormones may offer the opportunity to develop successful treatments for obesity. Here we review the current understanding of the role of gut hormones and the hypothalamus on food intake and body weight control.
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Affiliation(s)
- Keisuke Suzuki
- Section of Investigative Medicine, Imperial College London, London, UK
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Mattes RD. Oral Fat Exposure Pattern and Lipid Loading Effects on the Serum Triacylglycerol Concentration of Humans. CHEMOSENS PERCEPT 2009; 2:180-185. [PMID: 20352072 DOI: 10.1007/s12078-009-9062-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Orosensory exposure to dietary fat elicits an early, transient spike (first phase; minutes 0-60) and augmented, more sustained postprandial (second phase; minutes 120-360) elevation of serum triacylglycerol (TAG) in humans. To assess the physiological significance of these effects, TAG concentrations were monitored following manipulation of the oral exposure pattern and accompanying lipid load. Fifteen healthy adults participated in a randomized, 6-arm, crossover design study. Conditions consisted of ingestion of 30-g loads of safflower oil, provided as capsules to bypass oral stimulation, followed by 15 min of oral stimulation (mastication and expectoration) with full-fat or nonfat cream cheese (conditions 1 and 2); the same oral load ingested intermittently with oral stimulation by both food forms (conditions 3 and 4); and 10-g lipid loads ingested with intermittent oral stimulation by both food forms (conditions 5 and 6). Blood was collected via an indwelling catheter and TAG was measured at minutes -15, 0, 10, 20, 30, 40, 50, 60, 120, 240, and 360 relative to the onset of sensory stimulation. Testing was conducted weekly. Sequential (lipid loading followed by oral stimulation) and intermittent (intermixed lipid loading and oral stimulation) conditions led to comparable TAG responses. Significant first- and second-phase TAG concentration increases were observed with the 30-g loads, but not the 10-g loads. TAG responses to the full-fat and nonfat stimuli were similar. These data support the veracity of the earlier literature based on sequential oral exposure regimens and indicate that TAG responses reflect an interaction between oral fat signaling and gut lipid content. The augmentation of TAG associated specifically with dietary fat exposure, as compared to a nonfat food matched on other sensory properties, may only occur with higher fat loads.
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Affiliation(s)
- Richard D Mattes
- Department of Foods and Nutrition, Purdue University, 212 Stone Hall, 700 W State Street, West Lafayette, IN 47907-2059, USA
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Abstract
Taste is a chemical sense that aids in the detection of nutrients and guides food choice. A limited number of primary qualities comprise taste. Accumulating evidence has raised a question about whether fat should be among them. Most evidence indicates triacylglycerol is not an effective taste stimulus, though it clearly contributes sensory properties to foods by carrying flavor compounds and altering texture. However, there is increasing anatomical, electrophysiological, animal behavior, imaging, metabolic, and psychophysical evidence that free fatty acids are detectable when non-taste cues are minimized. Free fatty acids varying in saturation and chain length are detectable, suggesting the presence of multiple transduction mechanisms and/or a nonspecific mechanism in the oral cavity. However, confirmation of "fatty" as a taste primary will require additional studies that verify these observations are taste specific. Oral exposure to free fatty acids likely serves as a warning signal to discourage intake and influences lipid metabolism.
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Samra R. Fats and Satiety. Front Neurosci 2009. [DOI: 10.1201/9781420067767-c15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Neary MT, Batterham RL. Gut hormones: implications for the treatment of obesity. Pharmacol Ther 2009; 124:44-56. [PMID: 19560488 DOI: 10.1016/j.pharmthera.2009.06.005] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2009] [Accepted: 06/09/2009] [Indexed: 12/17/2022]
Abstract
Bariatric surgery is the only effective treatment for patients with morbid obesity. This is no solution to the present obesity pandemic however. Currently licensed non-surgical pharmaceuticals are of limited efficacy and alternatives are needed. Harnessing the body's own appetite-regulating signals is a desirable pharmacological strategy. The gastrointestinal tract has a prime role in sensing and signalling food intake to the brain. Gut hormones are key mediators of this information, including: peptide YY (PYY), pancreatic polypeptide (PP), glucagon-like peptide 1 (GLP-1), oxyntomodulin (OXM), ghrelin, amylin and cholecystokinin (CCK). This review summarises the latest knowledge regarding the physiological and pathophysiological role of gut hormones in regulating our food intake and how this knowledge could guide, or has guided, the development of weight-loss drugs. Up-to-date outcomes of clinical trials are evaluated and directions for the future suggested.
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Affiliation(s)
- Marianne T Neary
- Centre for Diabetes and Endocrinology, Department of Medicine, University College London, 5 University Street, London WC1E 6JJ, United Kingdom
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Lomenick JP, White JR, Smart EJ, Clasey JL, Anderson JW. Glucagon-like peptide 1 and pancreatic polypeptide responses to feeding in normal weight and overweight children. J Pediatr Endocrinol Metab 2009; 22:493-500. [PMID: 19694196 DOI: 10.1515/jpem.2009.22.6.493] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
BACKGROUND Glucagon-like peptide 1 (GLP-1) and pancreatic polypeptide (PP) are intestinal hormones that are involved in the post-prandial satiety response. We sought to assess meal-related changes in these hormones in young children and determine whether differences exist between normal weight (NW) and overweight (OW) children. METHODS Seven to 11-year-old healthy NW (n=20) and OW (n=12) volunteers were given a standardized breakfast and lunch following an overnight fast and had measurements of GLP-1 and PP over 9 hours. We characterized whether GLP-1 and PP changed from the pre-prandial to the post-prandial state and whether the serum levels corresponded to reported appetite. RESULTS GLP-1 did not increase after eating, did not decline prior to the next meal, and did not correspond to satiety ratings in either group. PP increased post-prandially in OW children after both breakfast and lunch, but in the NW group PP only increased after breakfast. PP levels did not decline in either group as the next meal approached. CONCLUSIONS In our study of school-age children, feeding had little effect on GLP-1 secretion and a variable effect on serum PP levels. Observed differences in the GLP-1 and PP responses between the NW and OW groups do not suggest there is an intrinsic abnormality in their secretion that causes weight gain.
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Hwang JJ, Chan JL, Ntali G, Malkova D, Mantzoros CS. Leptin does not directly regulate the pancreatic hormones amylin and pancreatic polypeptide: interventional studies in humans. Diabetes Care 2008; 31:945-51. [PMID: 18252898 PMCID: PMC2753255 DOI: 10.2337/dc07-2433] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Leptin and the pancreatic hormones amylin and pancreatic polypeptide are being evaluated alone or in combination for the treatment of obesity, but their physiological regulation has not yet been fully elucidated. Thus, we examined whether amylin and pancreatic polypeptide are regulated by caloric intake and/or short- and long-term energy deprivation and whether any potential regulation is mediated by changes in leptin levels. RESEARCH DESIGN AND METHODS We measured circulating levels of amylin and pancreatic polypeptide after 1) a 75-g glucose load in 28 healthy, normal-weight women, 2) 72-h complete energy deficiency (severe hypoleptinemia) with administration of either placebo or replacement-dose recombinant methionyl human leptin (r-metHuLeptin) in normal-weight men (n = 6) and women (n = 7), and 3) chronic mild energy deficiency (mild hypoleptinemia) in 7 women with hypothalamic amenorrhea before and after r-metHuLeptin administration for 3 months. RESULTS Amylin and pancreatic polypeptide levels increased 15 min after a 75-g glucose load and remained elevated at 60 and 120 min (P < 0.0001). Fasting for 72 h decreased leptin (to 21%) and amylin (to 67%) of baseline but not pancreatic polypeptide levels. Normalizing leptin levels with r-metHuLeptin did not alter the fasting-induced decrease in amylin and had no effect on pancreatic polypeptide levels. Neither amylin nor pancreatic polypeptide levels were different in leptin-deficient women with hypothalamic amenorrhea compared with weight-matched control subjects, and normalization of leptin levels with r-metHuLeptin treatment did not alter amylin or pancreatic polypeptide levels. CONCLUSIONS Circulating amylin levels increase after a glucose load and decrease in response to short-term complete fasting, but these changes are not mediated by leptin.
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Affiliation(s)
- Janice J Hwang
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
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Bradford B, Harvatine K, Allen M. Dietary Unsaturated Fatty Acids Increase Plasma Glucagon-Like Peptide-1 and Cholecystokinin and May Decrease Premeal Ghrelin in Lactating Dairy Cows. J Dairy Sci 2008; 91:1443-50. [DOI: 10.3168/jds.2007-0670] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Affiliation(s)
- Owais B. Chaudhri
- Department of Metabolic Medicine, Imperial College London, Hammersmith Hospital, London W12 0NN, United Kingdom;
| | - Victoria Salem
- Department of Metabolic Medicine, Imperial College London, Hammersmith Hospital, London W12 0NN, United Kingdom;
| | - Kevin G. Murphy
- Department of Metabolic Medicine, Imperial College London, Hammersmith Hospital, London W12 0NN, United Kingdom;
| | - Stephen R. Bloom
- Department of Metabolic Medicine, Imperial College London, Hammersmith Hospital, London W12 0NN, United Kingdom;
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Abstract
The current obesity epidemic is fuelled by the availability of highly palatable, calorie-dense food, and the low requirement for physical activity in our modern environment. If energy intake exceeds energy use, the excess calories are stored as body fat. Although the body has mechanisms that act to maintain body weight over time, they primarily defend against starvation and are less robust in preventing the development of obesity. Knowledge of this homeostatic system that controls body weight has increased exponentially over the last decade and has revealed new possibilities for the treatment of obesity and its associated comorbidities. One therapeutic target is the development of agents based on the gastrointestinal hormones that control appetite. This review discusses the hormones oxyntomodulin, peptide YY, glucagon-like peptide 1, pancreatic polypeptide, and ghrelin and their emerging potential as anti-obesity treatments.
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Affiliation(s)
- Owais B Chaudhri
- Department of Metabolic Medicine, Imperial College London, 6th Floor Commonwealth Building, Hammersmith Hospital, Du Cane Rd., London W12 0NN, UK
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41
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Field BCT, Wren AM, Cooke D, Bloom SR. Gut Hormones as Potential New Targets for Appetite Regulation and the Treatment of Obesity. Drugs 2008; 68:147-63. [DOI: 10.2165/00003495-200868020-00002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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42
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Samra RA, Anderson GH. Insoluble cereal fiber reduces appetite and short-term food intake and glycemic response to food consumed 75 min later by healthy men. Am J Clin Nutr 2007; 86:972-9. [PMID: 17921373 DOI: 10.1093/ajcn/86.4.972] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Insoluble fiber consumption is associated with reduced risk of obesity and diabetes, but its mechanisms of action are unknown. OBJECTIVE The objective was to describe the effect of insoluble fiber on appetite, short-term food intake, and blood glucose (BG) before and after a meal 75 min later in healthy men. DESIGN In a crossover design, high-fiber (HF; 33 g insoluble fiber) cereal, low-fiber (LF) cereal, white bread (WB), and water control were administered to young men after an overnight fast. Caloric treatments had similar energy, macronutrient content, volume, and weight. In the first experiment, subjective appetite and BG were measured at 15-min intervals before and after an ad libitum meal at 75 min. In the second experiment, a preset pizza meal (850 kcal) was consumed at 75 min. Appetite and blood glucose were measured for 150 min at fasting and at 15-min intervals before and after the fixed meal. RESULTS In experiment 1, ad libitum food intake was lower after the HF cereal and WB than after the LF cereal and water (937 +/- 86, 970 +/- 65, 1109 +/- 90, 1224 +/- 89 kcal, respectively; P < 0.001). Appetite was lower (P < 0.05) after the HF cereal than after the WB but not different from the LF cereal. The BG area under the curve (AUC) did not differ among the HF cereal, WB, and LF cereal from 0 to 75 min, but the postmeal BG increased after the WB and LF cereal but not after the HF cereal. In experiment 2, the HF cereal, but not the LF cereal or WB, increased fullness before and prevented an increase in the BG AUC after the preset meal (P < 0.05). CONCLUSION A serving of 33 g insoluble fiber reduced appetite, lowered food intake, and reduced glycemic response to a meal consumed 75 min later.
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Affiliation(s)
- Rania Abou Samra
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
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43
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Frecka JM, Hollis JH, Mattes RD. Effects of appetite, BMI, food form and flavor on mastication: almonds as a test food. Eur J Clin Nutr 2007; 62:1231-8. [PMID: 17637602 DOI: 10.1038/sj.ejcn.1602838] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVES To investigate the effects of appetitive sensations, body mass index (BMI) and physical/sensory properties of food (almonds) on masticatory indices and resultant pre-swallowing particle sizes. SUBJECTS/METHODS Twelve lean (BMI=22.2+/-0.3) and 12 obese (BMI=34.3+/-0.6) adults. After collecting appetitive ratings, electromyographic recordings were used to assess participants' microstructure of eating for five almond products (raw, dry unsalted roasted, natural sliced, roasted salted and honey roasted) under fasted and satiated conditions. Duplicate samples were masticated to the point of deglutition and then were expectorated and size sorted. RESULTS No statistically significant effects of BMI were detected for any of the mastication measures. Maximum and mean bite forces were greater under the fasted condition. Sliced almonds required lower bite force than did the other almond varieties. The pre-swallowing particle sizes were significantly greater for the sliced almonds than all other varieties. Both the number of chews and mastication time were negatively correlated with particle size. There were no significant effects of almond form or flavor on particle size. CONCLUSIONS These results do not support differences in masticatory performance between lean and obese individuals, nor effects of sensory properties. Instead, the physical form of foods as well as an individuals' appetitive state may have a greater influence on masticatory behavior. The health implications of these observations warrant further investigation.
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Affiliation(s)
- J M Frecka
- Department of Foods and Nutrition, Purdue University, 700 West State Street, West Lafayette, IN 47907, USA
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44
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Abstract
The neuropeptide Y system - comprising neuropeptide Y, peptide YY, pancreatic polypeptide and the Y receptors through which they act (Y1, Y2, Y4, Y5 and y6) - has been at the center of attention with regards to regulation of feeding behavior and its possible involvement in obesity. In the past, research has focused mainly on the orexigenic and obesogenic action of this system, with Y1 and Y5 receptors being prime candidates as mediators of neuropeptide Y-induced hyperphagia and obesity. However, in recent years, the role of other members of the neuropeptide Y family, peptide YY, pancreatic polypeptide and the Y2 and Y4 receptors through which they predominantly act, have commanded increasing attention on account of their effects to mediate satiety and promote weight loss via actions in key brain structures, such as the arcuate nucleus of the hypothalamus and the brain stem. This review focuses on the role of peptide YY- and pancreatic polypeptide-like compounds as possible antiobesity drugs, taking into account their effects, not only on energy balance, but also in the regulation of bone formation, and highlights potential benefits of using Y2 and/or Y4 antagonists (as opposed to agonists such as peptide YY or pancreatic polypeptide) in the treatment of obesity.
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Affiliation(s)
- En-Ju D Lin
- a Research Officer, The Garvan Institute of Medical Research, Neuroscience Research Program, 384 Victoria Street, Darlinghurst NSW 2010, Sydney, Australia.
| | - Lei Zhang
- b Research Officer, The Garvan Institute of Medical Research, Neuroscience Research Program, 384 Victoria Street, Darlinghurst NSW 2010, Sydney, Australia.
| | - Amanda Sainsbury
- c Research Fellow, The Garvan Institute of Medical Research, Neuroscience Research Program, 384 Victoria Street, Darlinghurst NSW 2010, Sydney, Australia.
| | - Herbert Herzog
- d Director of Neuroscience Research Program, The Garvan Institute of Medical Research, Neuroscience Research Program, 384 Victoria Street, Darlinghurst NSW 2010, Sydney, Australia.
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45
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Abstract
The role of gastrointestinal hormones in the regulation of appetite is reviewed. The gastrointestinal tract is the largest endocrine organ in the body. Gut hormones function to optimize the process of digestion and absorption of nutrients by the gut. In this capacity, their local effects on gastrointestinal motility and secretion have been well characterized. By altering the rate at which nutrients are delivered to compartments of the alimentary canal, the control of food intake arguably constitutes another point at which intervention may promote efficient digestion and nutrient uptake. In recent decades, gut hormones have come to occupy a central place in the complex neuroendocrine interactions that underlie the regulation of energy balance. Many gut peptides have been shown to influence energy intake. The most well studied in this regard are cholecystokinin (CCK), pancreatic polypeptide, peptide YY, glucagon-like peptide-1 (GLP-1), oxyntomodulin and ghrelin. With the exception of ghrelin, these hormones act to increase satiety and decrease food intake. The mechanisms by which gut hormones modify feeding are the subject of ongoing investigation. Local effects such as the inhibition of gastric emptying might contribute to the decrease in energy intake. Activation of mechanoreceptors as a result of gastric distension may inhibit further food intake via neural reflex arcs. Circulating gut hormones have also been shown to act directly on neurons in hypothalamic and brainstem centres of appetite control. The median eminence and area postrema are characterized by a deficiency of the blood-brain barrier. Some investigators argue that this renders neighbouring structures, such as the arcuate nucleus of the hypothalamus and the nucleus of the tractus solitarius in the brainstem, susceptible to influence by circulating factors. Extensive reciprocal connections exist between these areas and the hypothalamic paraventricular nucleus and other energy-regulating centres of the central nervous system. In this way, hormonal signals from the gut may be translated into the subjective sensation of satiety. Moreover, the importance of the brain-gut axis in the control of food intake is reflected in the dual role exhibited by many gut peptides as both hormones and neurotransmitters. Peptides such as CCK and GLP-1 are expressed in neurons projecting both into and out of areas of the central nervous system critical to energy balance. The global increase in the incidence of obesity and the associated burden of morbidity has imparted greater urgency to understanding the processes of appetite control. Appetite regulation offers an integrated model of a brain-gut axis comprising both endocrine and neurological systems. As physiological mediators of satiety, gut hormones offer an attractive therapeutic target in the treatment of obesity.
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Affiliation(s)
| | | | - Steve Bloom
- Department of Metabolic Medicine, Imperial College Faculty of MedicineHammersmith Hospital, Du Cane Road, London W12 ONN, UK
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Ernst A, Hellmich S, Bergmann A. Proneurotensin 1-117, a stable neurotensin precursor fragment identified in human circulation. Peptides 2006; 27:1787-93. [PMID: 16519961 DOI: 10.1016/j.peptides.2006.01.021] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2005] [Revised: 01/25/2006] [Accepted: 01/26/2006] [Indexed: 11/30/2022]
Abstract
Proneurotensin/neuromedin N (pro NT/NMN) is the common precursor of two biologically active peptides, neurotensin (NT) and neuromedin N (NMN). We have established antibodies against peptide sequences of the NT/NMN precursor and developed a sandwich immunoassay for the detection of pro NT/NMN immunoreactivity in human circulation. Endogenous pro NT/NMN immunoreactivity was enriched by affinity chromatography using antibodies against two different pro NT/NMN epitopes, and further purified by reversed phase HPLC. Mass spectrometry analysis revealed pro NT/NMN 1-117 as major pro NT/NMN immunoreactivity in human circulation. Pro NT/NMN 1-117 is detectable in serum from healthy individuals (n = 124; median 338.9 pmol/L). As known for NT, the release of pro NT/NMN 1-117 from the intestine into the circulation is stimulated by ingestion of an ordinary meal. Investigation of the pro NT/NMN 1-117 in vitro stability in human serum and plasma revealed that this molecule is stable for at least 48 h at room temperature. Since pro NT/NMN 1-117 is theoretically produced during precursor processing in stoichiometric amounts relative to NT and NMN, it could be a surrogate marker for the release of these bioactive peptides.
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Affiliation(s)
- A Ernst
- SphingoTec GmbH, Tulpenweg 6, D-16556 Borgsdorf, Germany.
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47
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Abstract
The chemical senses (taste, smell, and chemical irritation) convey information from the external to the internal environment. This information influences an organism's quality of life, safety, reproductive function, and, to the present point, nutritional status. To illustrate this role, the effects of chemosensory stimulation on food choice, gastrointestinal function, and energy balance will be briefly reviewed. Each role is achieved, in part, by the chemosensory cue initiating anticipatory responses for an impending homeostatic challenge, a meal.
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Affiliation(s)
- Richard D Mattes
- Department of Foods and Nutrition, Purdue University, 700 West State Street, West Lafayette, IN 47907-2059, USA.
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48
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Reinehr T, Enriori PJ, Harz K, Cowley MA, Roth CL. Pancreatic polypeptide in obese children before and after weight loss. Int J Obes (Lond) 2006; 30:1476-81. [PMID: 16702998 DOI: 10.1038/sj.ijo.0803393] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE Little is known concerning pancreatic polypeptide (PP) in weight loss and in childhood obesity. METHODS Fasting PP, leptin and insulin concentrations were determined in 38 obese children and compared with 35 lean children of the same age, gender and pubertal stage. Furthermore, changes of PP concentrations over a 1-year period were analyzed in the obese children participating in a weight loss intervention program. RESULTS Obese children had significantly (P<0.01) lower PP, and higher leptin and insulin levels compared to lean children. In multiple linear regression analysis, PP was significantly negatively correlated to body mass index (P<0.01), but not to leptin, insulin, age, gender and pubertal stage. Changes of PP did not significantly correlate to changes of insulin (r=0.07, P=0.343) and leptin (r=-0.02, P=0.459). The substantial weight loss in 17 children led to a significant (P<0.05) increase in PP and decrease in insulin and leptin. In the 21 children without substantial weight loss, there were no significant changes in PP, insulin and leptin. CONCLUSIONS PP concentrations are decreased in obese children and independent of age, gender, pubertal stage, leptin and insulin. The decrease of PP in obese children normalized after weight loss. Therefore, low PP concentrations reflect the overweight status, rather than cause it.
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Affiliation(s)
- T Reinehr
- Vestische Hospital for Children and Adolescents Datteln, University of Witten/Herdecke, Datteln, Germany.
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49
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Abstract
There is a growing worldwide epidemic of obesity. Obese people have a higher incidence of type 2 diabetes and cardiovascular disease, and hence present increasing social, financial and health burdens. Weight loss is always difficult to achieve through lifestyle changes alone, and currently licensed anti-obesity drug treatments, such as orlistat and sibutramine, if tolerated, only achieve modest weight loss. Therefore, there is a need to identify more potent pharmacological targets. In the last 10 years, discoveries of new hormones such as leptin and ghrelin, together with greater understanding of previously described hormones such as cholecystokinin (CCK), pancreatic polypeptide (PP), peptide YY (PYY) and glucagon-like peptide 1 (GLP-1), have led to a rapid increase in our knowledge of the regulation of energy balance. Among the most important factors, controlling appetite and satiety are peptide hormones released from the gut. In this paper, we provide a full up-to-date overview of the current state of knowledge of this field, together with the potential of these peptides as drugs, or as other therapeutic targets, in the treatment of obesity. Finally, we propose an integrated model to describe the complex interplay of these hormones in the broader physiology of energy balance.
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Affiliation(s)
- M S B Huda
- Diabetes and Endocrinology Research Group, University Hospital Aintree, Longmoor Lane, Liverpool, UK.
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50
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Abstract
Our knowledge of the physiological systems controlling energy homeostasis has increased dramatically over the last decade. The roles of peripheral signals from adipose tissue, pancreas, and the gastrointestinal tract reflecting short- and long-term nutritional status are now being described. Such signals influence central circuits in the hypothalamus, brain stem, and limbic system to modulate neuropeptide release and hence food intake and energy expenditure. This review discusses the peripheral hormones and central neuronal pathways that contribute to control of appetite.
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Affiliation(s)
- Sarah Stanley
- Endocrine Unit, Imperial College Faculty of Medicine, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
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