101
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Wu T, Thazhath SS, Marathe CS, Bound MJ, Jones KL, Horowitz M, Rayner CK. Comparative effect of intraduodenal and intrajejunal glucose infusion on the gut-incretin axis response in healthy males. Nutr Diabetes 2015; 5:e156. [PMID: 25985092 PMCID: PMC4450461 DOI: 10.1038/nutd.2015.6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 03/22/2015] [Accepted: 04/05/2015] [Indexed: 02/07/2023] Open
Abstract
The region of enteral nutrient exposure may be an important determinant of postprandial incretin hormone secretion and blood glucose homoeostasis. We compared responses of plasma glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), insulin and glucagon, and blood glucose to a standardised glucose infusion into the proximal jejunum and duodenum in healthy humans. Ten healthy males were evaluated during a standardised glucose infusion (2 kcal min(-1) over 120 min) into the proximal jejunum (50 cm post pylorus) and were compared with another 10 healthy males matched for ethnicity, age and body mass index who received an identical glucose infusion into the duodenum (12 cm post pylorus). Blood was sampled frequently for measurements of blood glucose and plasma hormones. Plasma GLP-1, GIP and insulin responses, as well as the insulin:glucose ratio and the insulinogenic index 1 (IGI1) were greater (P<0.05 for each) after intrajejunal (i.j.) than intraduodenal glucose infusion, without a significant difference in blood glucose or plasma glucagon. Pooled analyses revealed direct relationships between IGI1 and the responses of GLP-1 and GIP (r=0.48 and 0.56, respectively, P<0.05 each), and between glucagon and GLP-1 (r=0.70, P<0.001). In conclusion, i.j. glucose elicits greater incretin hormone and insulin secretion than intraduodenal glucose in healthy humans, suggesting regional specificity of the gut-incretin axis.
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Affiliation(s)
- T Wu
- Discipline of Medicine, The University of Adelaide, Royal Adelaide Hospital, Adelaide, South Australia, Australia
- Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, South Australia, Australia
| | - S S Thazhath
- Discipline of Medicine, The University of Adelaide, Royal Adelaide Hospital, Adelaide, South Australia, Australia
- Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, South Australia, Australia
| | - C S Marathe
- Discipline of Medicine, The University of Adelaide, Royal Adelaide Hospital, Adelaide, South Australia, Australia
- Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, South Australia, Australia
| | - M J Bound
- Discipline of Medicine, The University of Adelaide, Royal Adelaide Hospital, Adelaide, South Australia, Australia
- Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, South Australia, Australia
| | - K L Jones
- Discipline of Medicine, The University of Adelaide, Royal Adelaide Hospital, Adelaide, South Australia, Australia
- Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, South Australia, Australia
| | - M Horowitz
- Discipline of Medicine, The University of Adelaide, Royal Adelaide Hospital, Adelaide, South Australia, Australia
- Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, South Australia, Australia
| | - C K Rayner
- Discipline of Medicine, The University of Adelaide, Royal Adelaide Hospital, Adelaide, South Australia, Australia
- Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, South Australia, Australia
- Discipline of Medicine, The University of Adelaide, Royal Adelaide Hospital, Level 6, Eleanor Harald Building, North Terrace, Adelaide 5000, South Australia, Australia. E-mail:
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102
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Tsuda T. Possible abilities of dietary factors to prevent and treat diabetes via the stimulation of glucagon-like peptide-1 secretion. Mol Nutr Food Res 2015; 59:1264-73. [PMID: 25707985 DOI: 10.1002/mnfr.201400871] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 02/01/2015] [Accepted: 02/09/2015] [Indexed: 12/22/2022]
Abstract
There is a pressing need for countermeasures against diabetes, which has increased in incidence, becoming a global issue. Glucagon-like peptide-1 (GLP-1), a molecule secreted in enteroendocrine L cells in the lower small and large intestines, is thought to be one of the most important molecular targets for the prevention and treatment of diabetes. There has been increasing interest in the possible ability of dietary factors to treat diabetes via modulating GLP-1 secretion. There is thought to be a close relationship between incretin and diet, and the purported best approach for using dietary factors to increase GLP-1 activity is promotion of secretion of endogenous GLP-1. It have been reported that nutrients as well as various non-nutrient dietary factors can function as GLP-1 secretogogues. Here, we present our findings on the GLP-1 secretion-stimulating functions of two dietary factors, curcumin and extract of edible sweet potato leaves, which contain caffeoylquinic acid derivatives. However, it is necessary to reveal in greater detail the stimulation of GLP-1 secretion by dietary factors for preventing and treating diabetes. It is desirable to clarify the exact GLP-1 secretory pathway, the effect of metabolites derived from dietary factors in gut lumen, and the relationship between incretin and meal.
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Affiliation(s)
- Takanori Tsuda
- College of Bioscience and Biotechnology, Chubu University, Kasugai, Aichi, Japan
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103
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Phillips LK, Deane AM, Jones KL, Rayner CK, Horowitz M. Gastric emptying and glycaemia in health and diabetes mellitus. Nat Rev Endocrinol 2015; 11:112-28. [PMID: 25421372 DOI: 10.1038/nrendo.2014.202] [Citation(s) in RCA: 175] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The rate of gastric emptying is a critical determinant of postprandial glycaemia and, accordingly, is fundamental to maintaining blood glucose homeostasis. Disordered gastric emptying occurs frequently in patients with longstanding type 1 diabetes mellitus and type 2 diabetes mellitus (T2DM). A complex bidirectional relationship exists between gastric emptying and glycaemia--gastric emptying accounts for ∼35% of the variance in peak postprandial blood glucose concentrations in healthy individuals and in patients with diabetes mellitus, and the rate of emptying is itself modulated by acute changes in glycaemia. Clinical implementation of incretin-based therapies for the management of T2DM, which diminish postprandial glycaemia, in part by slowing gastric emptying, is widespread. Other therapies for patients with T2DM, which specifically target gastric emptying include pramlintide and dietary-based treatment approaches. A weak association exists between upper gastrointestinal symptoms and the rate of gastric emptying. In patients with severe diabetic gastroparesis, pathological changes are highly variable and are characterized by loss of interstitial cells of Cajal and an immune infiltrate. Management options for patients with symptomatic gastroparesis remain limited in their efficacy, which probably reflects the heterogeneous nature of the underlying pathophysiology.
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Affiliation(s)
- Liza K Phillips
- Centre of Research Excellence in Translating Nutritional Science to Good Health, Discipline of Medicine, The University of Adelaide, Level 6 Eleanor Harrald Building, Royal Adelaide Hospital, Frome Road, Adelaide, SA 5005, Australia
| | - Adam M Deane
- Centre of Research Excellence in Translating Nutritional Science to Good Health, Discipline of Medicine, The University of Adelaide, Level 6 Eleanor Harrald Building, Royal Adelaide Hospital, Frome Road, Adelaide, SA 5005, Australia
| | - Karen L Jones
- Centre of Research Excellence in Translating Nutritional Science to Good Health, Discipline of Medicine, The University of Adelaide, Level 6 Eleanor Harrald Building, Royal Adelaide Hospital, Frome Road, Adelaide, SA 5005, Australia
| | - Chris K Rayner
- Centre of Research Excellence in Translating Nutritional Science to Good Health, Discipline of Medicine, The University of Adelaide, Level 6 Eleanor Harrald Building, Royal Adelaide Hospital, Frome Road, Adelaide, SA 5005, Australia
| | - Michael Horowitz
- Centre of Research Excellence in Translating Nutritional Science to Good Health, Discipline of Medicine, The University of Adelaide, Level 6 Eleanor Harrald Building, Royal Adelaide Hospital, Frome Road, Adelaide, SA 5005, Australia
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104
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Kuhre RE, Frost CR, Svendsen B, Holst JJ. Molecular mechanisms of glucose-stimulated GLP-1 secretion from perfused rat small intestine. Diabetes 2015; 64:370-82. [PMID: 25157092 DOI: 10.2337/db14-0807] [Citation(s) in RCA: 123] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Glucose is an important stimulus for glucagon-like peptide 1 (GLP-1) secretion, but the mechanisms of secretion have not been investigated in integrated physiological models. We studied glucose-stimulated GLP-1 secretion from isolated perfused rat small intestine. Luminal glucose (5% and 20% w/v) stimulated the secretion dose dependently, but vascular glucose was without significant effect at 5, 10, 15, and 25 mmol/L. GLP-1 stimulation by luminal glucose (20%) secretion was blocked by the voltage-gated Ca channel inhibitor, nifedipine, or by hyperpolarization with diazoxide. Luminal administration (20%) of the nonmetabolizable sodium-glucose transporter 1 (SGLT1) substrate, methyl-α-D-glucopyranoside (α-MGP), stimulated release, whereas the SGLT1 inhibitor phloridzin (luminally) abolished responses to α-MGP and glucose. Furthermore, in the absence of luminal NaCl, luminal glucose (20%) did not stimulate a response. Luminal glucose-stimulated GLP-1 secretion was also sensitive to luminal GLUT2 inhibition (phloretin), but in contrast to SGLT1 inhibition, phloretin did not eliminate the response, and luminal glucose (20%) stimulated larger GLP-1 responses than luminal α-MGP in matched concentrations. Glucose transported by GLUT2 may act after metabolization, closing KATP channels similar to sulfonylureas, which also stimulated secretion. Our data indicate that SGLT1 activity is the driving force for glucose-stimulated GLP-1 secretion and that KATP-channel closure is required to stimulate a full-blown glucose-induced response.
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Affiliation(s)
- Rune E Kuhre
- Novo Nordisk Foundation Center for Basic Metabolic Research and Department of Biomedical Sciences, the Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Charlotte R Frost
- Novo Nordisk Foundation Center for Basic Metabolic Research and Department of Biomedical Sciences, the Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Berit Svendsen
- Novo Nordisk Foundation Center for Basic Metabolic Research and Department of Biomedical Sciences, the Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Jens J Holst
- Novo Nordisk Foundation Center for Basic Metabolic Research and Department of Biomedical Sciences, the Panum Institute, University of Copenhagen, Copenhagen, Denmark
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105
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Thazhath SS, Wu T, Bound MJ, Checklin HL, Jones KL, Willoughby S, Horowitz M, Rayner CK. Changes in meal composition and duration affect postprandial endothelial function in healthy humans. Am J Physiol Gastrointest Liver Physiol 2014; 307:G1191-7. [PMID: 25342049 DOI: 10.1152/ajpgi.00323.2014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Endothelial function, measured by flow-mediated dilatation (FMD), predicts cardiovascular events and is impaired postprandially. The objective of this study was to evaluate the effects of changes in composition or duration of ingestion of a meal, which slows gastric emptying and/or small intestinal nutrient exposure, on postprandial endothelial function. Twelve healthy subjects (6 male, 6 female; 33 ± 6 yr) were each studied on three occasions, in a randomized crossover design. After an overnight fast, subjects consumed a [(13)C]octanoic acid-labeled mashed potato meal ("meal 1"), or meal 1 mixed with 9 g guar ("meal 2") within 10 min, or meal 1 divided into 12 equal portions over 60 min ("meal 3"). Brachial artery FMD was measured every 30 min for 120 min. Blood glucose, serum insulin, and gastric emptying (breath test) were evaluated for 240 min. Data are means ± SE. Compared with meal 1, meal 2 was associated with slower gastric emptying (half-emptying time 285 ± 27 vs. 208 ± 15 min, P < 0.05), lower postprandial blood glucose and insulin (P < 0.001 for both), and a delayed, but more sustained, suppression of FMD (P < 0.001). After meal 3, both glycemic increment and reduction in FMD were less than after meal 2 (P < 0.05 for both). The decrement in FMD was directly related to the increment in blood glucose (r = 0.46, P = 0.02). We conclude that, in health, postprandial FMD is influenced by perturbation of gastric emptying and the duration of meal consumption, which also impact on glycemia.
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Affiliation(s)
- Sony S Thazhath
- Discipline of Medicine, The University of Adelaide, Royal Adelaide Hospital, Adelaide, Australia; Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, Australia; and
| | - Tongzhi Wu
- Discipline of Medicine, The University of Adelaide, Royal Adelaide Hospital, Adelaide, Australia; Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, Australia; and
| | - Michelle J Bound
- Discipline of Medicine, The University of Adelaide, Royal Adelaide Hospital, Adelaide, Australia; Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, Australia; and
| | - Helen L Checklin
- Discipline of Medicine, The University of Adelaide, Royal Adelaide Hospital, Adelaide, Australia; Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, Australia; and
| | - Karen L Jones
- Discipline of Medicine, The University of Adelaide, Royal Adelaide Hospital, Adelaide, Australia; Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, Australia; and
| | - Scott Willoughby
- Discipline of Medicine, The University of Adelaide, Royal Adelaide Hospital, Adelaide, Australia; Centre for Heart Rhythm Disorders, The University of Adelaide and Royal Adelaide Hospital, Adelaide, Australia
| | - Michael Horowitz
- Discipline of Medicine, The University of Adelaide, Royal Adelaide Hospital, Adelaide, Australia; Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, Australia; and
| | - Christopher K Rayner
- Discipline of Medicine, The University of Adelaide, Royal Adelaide Hospital, Adelaide, Australia; Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, Australia; and
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106
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Araújo JR, Martel F, Keating E. Exposure to non-nutritive sweeteners during pregnancy and lactation: Impact in programming of metabolic diseases in the progeny later in life. Reprod Toxicol 2014; 49:196-201. [PMID: 25263228 DOI: 10.1016/j.reprotox.2014.09.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Revised: 07/11/2014] [Accepted: 09/15/2014] [Indexed: 12/11/2022]
Abstract
The nutritional environment during embryonic, fetal and neonatal development plays a crucial role in the offspring's risk of developing diseases later in life. Although non-nutritive sweeteners (NNS) provide sweet taste without contributing to energy intake, animal studies showed that long-term consumption of NSS, particularly aspartame, starting during the perigestational period may predispose the offspring to develop obesity and metabolic syndrome later in life. In this paper, we review the impact of NNS exposure during the perigestational period on the long-term disease risk of the offspring, with a particular focus on metabolic diseases. Some mechanisms underlying NNS adverse metabolic effects have been proposed, such as an increase in intestinal glucose absorption, alterations in intestinal microbiota, induction of oxidative stress and a dysregulation of appetite and reward responses. The data reviewed herein suggest that NNS consumption by pregnant and lactating women should be looked with particular caution and requires further research.
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Affiliation(s)
- João Ricardo Araújo
- Department of Biochemistry (U38-FCT), Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal.
| | - Fátima Martel
- Department of Biochemistry (U38-FCT), Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal
| | - Elisa Keating
- Department of Biochemistry (U38-FCT), Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal; Center for Biotechnology and Fine Chemistry, School of Biotechnology, Portuguese Catholic University, 4200-702 Porto, Portugal
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107
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Abstract
PURPOSE OF REVIEW The consumption of low-calorie beverages has increased worldwide, mainly because of their combination of sweet taste without adding significant calories to the diet. However, some epidemiological studies have linked the higher consumption of low-calorie beverages with increased body weight gain. RECENT FINDINGS Although a matter of debate, this paradoxical association between low-calorie beverages and weight gain has been attributed to their effect on the enteral-brain axis. More specifically, artificial sweeteners present in low-calorie beverages could induce appetite increase, probably due to an ambiguous psychobiological signal (uncoupling sweet taste from calorie intake) that confounds the appetite's regulatory mechanisms, promoting overeating and, ultimately, leading to weight gain. However, many studies do not support this assumption, and the mechanisms underlying the interaction between low-calorie beverages and the enteral-brain axis remain to be defined. SUMMARY The understanding of the effects of low-calorie drinks on the enteral-brain axis still remains in its infancy and needs to be unveiled. The consumption of low-calorie beverages reduces the calories from that drink, but compensatory phenomena may increase energy intake, and if so must be recognized and avoided.
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Affiliation(s)
- Adaliene V M Ferreira
- aNutrition Department, Universidade Federal de Minas Gerais bInterdisciplinary Laboratory of Medical Investigation, School of Medicine, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
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108
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Pereira MA, Odegaard AO. Artificially sweetened beverages--do they influence cardiometabolic risk? Curr Atheroscler Rep 2014; 15:375. [PMID: 24190652 DOI: 10.1007/s11883-013-0375-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The sweeteners in artificially sweetened beverages (ASB) are potent stimulators of sweetness on the palate, yet contain no energy. This "mismatch" between sweetness and energy in ASB has raised concern about metabolism and health. This article provides a review of the recent literature on the effect of ASB on cardiometabolic risk factors and disease. Physiologic mechanisms are discussed, as well as epidemiologic studies. Prospective studies of ASB intake and the risk of obesity, diabetes, and cardiovascular disease have revealed inconsistent results. Higher-quality studies suggest either no effect of ASB or perhaps a protective effect through replacement of calorically dense alternatives. Although some studies have reported that ASB may increase risk, these observations appear to be an artifact of reverse causality. The limited experimental evidence does not support an effect of ASB on obesity or chronic disease. Indeed, experimental studies in humans suggest ASB may be effective for weight loss when replacing sugar-sweetened beverages.
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Affiliation(s)
- Mark A Pereira
- Division of Epidemiology & Community Health, School of Public Health, University of Minnesota, Minneapolis, MN, USA,
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109
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Thazhath SS, Wu T, Young RL, Horowitz M, Rayner CK. Glucose absorption in small intestinal diseases. Expert Rev Gastroenterol Hepatol 2014; 8:301-12. [PMID: 24502537 DOI: 10.1586/17474124.2014.887439] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Recent developments in the field of diabetes and obesity management have established the central role of the gut in glucose homeostasis; not only is the gut the primary absorptive site, but it also triggers neurohumoral feedback responses that regulate the pre- and post-absorptive phases of glucose metabolism. Structural and/or functional disorders of the intestine have the capacity to enhance (e.g.: diabetes) or inhibit (e.g.: short-gut syndrome, critical illness) glucose absorption, with potentially detrimental outcomes. In this review, we first describe the normal physiology of glucose absorption and outline the methods by which it can be quantified. Then we focus on the structural and functional changes in the small intestine associated with obesity, critical illness, short gut syndrome and other malabsorptive states, and particularly Type 2 diabetes, which can impact upon carbohydrate absorption and overall glucose homeostasis.
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Affiliation(s)
- Sony S Thazhath
- Discipline of Medicine, The University of Adelaide, Royal Adelaide Hospital, Adelaide, SA, Australia
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110
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Davidson TL, Sample CH, Swithers SE. An application of Pavlovian principles to the problems of obesity and cognitive decline. Neurobiol Learn Mem 2014; 108:172-84. [PMID: 23887140 PMCID: PMC3899105 DOI: 10.1016/j.nlm.2013.07.014] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 07/12/2013] [Accepted: 07/15/2013] [Indexed: 12/18/2022]
Abstract
An enormous amount of research has been aimed at identifying biological and environmental factors that are contributing to the current global obesity pandemic. The present paper reviews recent findings which suggest that obesity is attributable, at least in part, to a disruption of the Pavlovian control of energy regulation. Within our framework, this disruption occurs when (a) consumption of sweet-tasting, but low calorie or noncaloric, foods and beverages reduces the ability of sweet tastes to predict the postingestive caloric consequences of intake and (b) consuming diets high in saturated fat and sugar (a.k.a., Western diet) impairs hippocampal-dependent learning and memory processes that are involved with the use of interoceptive "satiety" signals to anticipate when food and eating are not followed by appetitive postingestive outcomes. The paper concludes with discussion of a "vicious-cycle" model which links obesity to cognitive decline.
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Affiliation(s)
- T L Davidson
- American University, Washington, DC, United States.
| | - C H Sample
- American University, Washington, DC, United States
| | - S E Swithers
- Purdue University, West Lafayette, IN, United States
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111
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Wu T, Rayner CK, Young RL, Horowitz M. Gut motility and enteroendocrine secretion. Curr Opin Pharmacol 2013; 13:928-34. [PMID: 24060702 DOI: 10.1016/j.coph.2013.09.002] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 08/16/2013] [Accepted: 09/04/2013] [Indexed: 02/07/2023]
Abstract
The motility of the gastrointestinal (GI) tract is modulated by complex neural and hormonal networks; the latter include gut peptides released from enteroendocrine cells during both the interdigestive and postprandial periods. Conversely, it is increasingly recognised that GI motility is an important determinant of gut hormone secretion, in that the transit of luminal contents influences the degree of nutrient stimulation of enteroendocrine cells in different gut regions, as well as the overall length of gut exposed to nutrient. Of particular interest is the relationship between gallbladder emptying and enteroendocrine secretion. The inter-relationships between GI motility and enteroendocrine secretion are central to blood glucose homeostasis, where an understanding is fundamental to the development of novel strategies for the management of diabetes mellitus.
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Affiliation(s)
- Tongzhi Wu
- Discipline of Medicine, University of Adelaide, Royal Adelaide Hospital, Adelaide, South Australia, Australia; Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Australia
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112
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Young RL, Chia B, Isaacs NJ, Ma J, Khoo J, Wu T, Horowitz M, Rayner CK. Disordered control of intestinal sweet taste receptor expression and glucose absorption in type 2 diabetes. Diabetes 2013; 62:3532-41. [PMID: 23761104 PMCID: PMC3781477 DOI: 10.2337/db13-0581] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We previously established that the intestinal sweet taste receptors (STRs), T1R2 and T1R3, were expressed in distinct epithelial cells in the human proximal intestine and that their transcript levels varied with glycemic status in patients with type 2 diabetes. Here we determined whether STR expression was 1) acutely regulated by changes in luminal and systemic glucose levels, 2) disordered in type 2 diabetes, and 3) linked to glucose absorption. Fourteen healthy subjects and 13 patients with type 2 diabetes were studied twice, at euglycemia (5.2 ± 0.2 mmol/L) or hyperglycemia (12.3 ± 0.2 mmol/L). Endoscopic biopsy specimens were collected from the duodenum at baseline and after a 30-min intraduodenal glucose infusion of 30 g/150 mL water plus 3 g 3-O-methylglucose (3-OMG). STR transcripts were quantified by RT-PCR, and plasma was assayed for 3-OMG concentration. Intestinal STR transcript levels at baseline were unaffected by acute variations in glycemia in healthy subjects and in type 2 diabetic patients. T1R2 transcript levels increased after luminal glucose infusion in both groups during euglycemia (+5.8 × 10(4) and +5.8 × 10(4) copies, respectively) but decreased in healthy subjects during hyperglycemia (-1.4 × 10(4) copies). T1R2 levels increased significantly in type 2 diabetic patients under the same conditions (+6.9 × 10(5) copies). Plasma 3-OMG concentrations were significantly higher in type 2 diabetic patients than in healthy control subjects during acute hyperglycemia. Intestinal T1R2 expression is reciprocally regulated by luminal glucose in health according to glycemic status but is disordered in type 2 diabetes during acute hyperglycemia. This defect may enhance glucose absorption in type 2 diabetic patients and exacerbate postprandial hyperglycemia.
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Affiliation(s)
- Richard L. Young
- Nerve-Gut Research Laboratory, University of Adelaide, Adelaide, South Australia, Australia
- Discipline of Medicine, University of Adelaide, Adelaide, South Australia, Australia
- Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, South Australia, Australia
- Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia, Australia
- Corresponding author: Richard L. Young,
| | - Bridgette Chia
- Nerve-Gut Research Laboratory, University of Adelaide, Adelaide, South Australia, Australia
- Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Nicole J. Isaacs
- Discipline of Medicine, University of Adelaide, Adelaide, South Australia, Australia
| | - Jing Ma
- Discipline of Medicine, University of Adelaide, Adelaide, South Australia, Australia
- Department of Endocrinology and Metabolism, Shanghai Renji Hospital, Shanghai Jiaotong University, Shanghai, China
| | - Joan Khoo
- Discipline of Medicine, University of Adelaide, Adelaide, South Australia, Australia
- Department of Endocrinology, Changi General Hospital, Singapore
| | - Tongzhi Wu
- Discipline of Medicine, University of Adelaide, Adelaide, South Australia, Australia
- Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, South Australia, Australia
| | - Michael Horowitz
- Discipline of Medicine, University of Adelaide, Adelaide, South Australia, Australia
- Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, South Australia, Australia
| | - Christopher K. Rayner
- Discipline of Medicine, University of Adelaide, Adelaide, South Australia, Australia
- Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, South Australia, Australia
- Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia, Australia
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113
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Swithers SE. Artificial sweeteners produce the counterintuitive effect of inducing metabolic derangements. Trends Endocrinol Metab 2013; 24:431-41. [PMID: 23850261 PMCID: PMC3772345 DOI: 10.1016/j.tem.2013.05.005] [Citation(s) in RCA: 259] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 04/29/2013] [Accepted: 05/21/2013] [Indexed: 02/06/2023]
Abstract
The negative impact of consuming sugar-sweetened beverages on weight and other health outcomes has been increasingly recognized; therefore, many people have turned to high-intensity sweeteners like aspartame, sucralose, and saccharin as a way to reduce the risk of these consequences. However, accumulating evidence suggests that frequent consumers of these sugar substitutes may also be at increased risk of excessive weight gain, metabolic syndrome, type 2 diabetes, and cardiovascular disease. This paper discusses these findings and considers the hypothesis that consuming sweet-tasting but noncaloric or reduced-calorie food and beverages interferes with learned responses that normally contribute to glucose and energy homeostasis. Because of this interference, frequent consumption of high-intensity sweeteners may have the counterintuitive effect of inducing metabolic derangements.
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Affiliation(s)
- Susan E Swithers
- Department of Psychological Sciences and Ingestive Behavior Research Center, Purdue University, 703 Third Street, West Lafayette, IN 47907, USA.
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114
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Pepino MY, Tiemann CD, Patterson BW, Wice BM, Klein S. Sucralose affects glycemic and hormonal responses to an oral glucose load. Diabetes Care 2013; 36:2530-5. [PMID: 23633524 PMCID: PMC3747933 DOI: 10.2337/dc12-2221] [Citation(s) in RCA: 161] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Nonnutritive sweeteners (NNS), such as sucralose, have been reported to have metabolic effects in animal models. However, the relevance of these findings to human subjects is not clear. We evaluated the acute effects of sucralose ingestion on the metabolic response to an oral glucose load in obese subjects. RESEARCH DESIGN AND METHODS Seventeen obese subjects (BMI 42.3 ± 1.6 kg/m(2)) who did not use NNS and were insulin sensitive (based on a homeostasis model assessment of insulin resistance score ≤ 2.6) underwent a 5-h modified oral glucose tolerance test on two separate occasions preceded by consuming either sucralose (experimental condition) or water (control condition) 10 min before the glucose load in a randomized crossover design. Indices of β-cell function, insulin sensitivity (SI), and insulin clearance rates were estimated by using minimal models of glucose, insulin, and C-peptide kinetics. RESULTS Compared with the control condition, sucralose ingestion caused 1) a greater incremental increase in peak plasma glucose concentrations (4.2 ± 0.2 vs. 4.8 ± 0.3 mmol/L; P = 0.03), 2) a 20 ± 8% greater incremental increase in insulin area under the curve (AUC) (P < 0.03), 3) a 22 ± 7% greater peak insulin secretion rate (P < 0.02), 4) a 7 ± 4% decrease in insulin clearance (P = 0.04), and 5) a 23 ± 20% decrease in SI (P = 0.01). There were no significant differences between conditions in active glucagon-like peptide 1, glucose-dependent insulinotropic polypeptide, glucagon incremental AUC, or indices of the sensitivity of the β-cell response to glucose. CONCLUSIONS These data demonstrate that sucralose affects the glycemic and insulin responses to an oral glucose load in obese people who do not normally consume NNS.
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Affiliation(s)
- M Yanina Pepino
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, Missouri, USA.
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115
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Wu T, Bound MJ, Zhao BR, Standfield SD, Bellon M, Jones KL, Horowitz M, Rayner CK. Effects of a D-xylose preload with or without sitagliptin on gastric emptying, glucagon-like peptide-1, and postprandial glycemia in type 2 diabetes. Diabetes Care 2013; 36:1913-8. [PMID: 23359361 PMCID: PMC3687261 DOI: 10.2337/dc12-2294] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVE Macronutrient "preloads" can reduce postprandial glycemia by slowing gastric emptying and stimulating glucagon-like peptide-1 (GLP-1) secretion. An ideal preload would entail minimal additional energy intake and might be optimized by concurrent inhibition of dipeptidyl peptidase-4 (DPP-4). We evaluated the effects of a low-energy D-xylose preload, with or without sitagliptin, on gastric emptying, plasma intact GLP-1 concentrations, and postprandial glycemia in type 2 diabetes. RESEARCH DESIGN AND METHODS Twelve type 2 diabetic patients were studied on four occasions each. After 100 mg sitagliptin (S) or placebo (P) and an overnight fast, patients consumed a preload drink containing either 50 g D-xylose (X) or 80 mg sucralose (control [C]), followed after 40 min by a mashed potato meal labeled with (13)C-octanoate. Blood was sampled at intervals. Gastric emptying was determined. RESULTS Both peak blood glucose and the amplitude of glycemic excursion were lower after PX and SC than PC (P < 0.01 for each) and were lowest after SX (P < 0.05 for each), while overall blood glucose was lower after SX than PC (P < 0.05). The postprandial insulin-to-glucose ratio was attenuated (P < 0.05) and gastric emptying was slower (P < 0.01) after D-xylose, without any effect of sitagliptin. Plasma GLP-1 concentrations were higher after D-xylose than control only before the meal (P < 0.05) but were sustained postprandially when combined with sitagliptin (P < 0.05). CONCLUSIONS In type 2 diabetes, acute administration of a D-xylose preload reduces postprandial glycemia and enhances the effect of a DPP-4 inhibitor.
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Affiliation(s)
- Tongzhi Wu
- Discipline of Medicine, University of Adelaide, Royal Adelaide Hospital, Adelaide, Australia
- Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia
| | - Michelle J. Bound
- Discipline of Medicine, University of Adelaide, Royal Adelaide Hospital, Adelaide, Australia
- Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia
| | - Beiyi R. Zhao
- Discipline of Medicine, University of Adelaide, Royal Adelaide Hospital, Adelaide, Australia
- Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia
| | - Scott D. Standfield
- Discipline of Medicine, University of Adelaide, Royal Adelaide Hospital, Adelaide, Australia
- Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia
| | - Max Bellon
- Department of Nuclear Medicine, Royal Adelaide Hospital, Adelaide, Australia
| | - Karen L. Jones
- Discipline of Medicine, University of Adelaide, Royal Adelaide Hospital, Adelaide, Australia
- Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia
| | - Michael Horowitz
- Discipline of Medicine, University of Adelaide, Royal Adelaide Hospital, Adelaide, Australia
- Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia
| | - Christopher K. Rayner
- Discipline of Medicine, University of Adelaide, Royal Adelaide Hospital, Adelaide, Australia
- Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia
- Corresponding author: Chris K. Rayner,
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116
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Marathe CS, Rayner CK, Jones KL, Horowitz M. Glucagon-like peptides 1 and 2 in health and disease: a review. Peptides 2013; 44:75-86. [PMID: 23523778 DOI: 10.1016/j.peptides.2013.01.014] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Revised: 01/30/2013] [Accepted: 01/30/2013] [Indexed: 02/07/2023]
Abstract
The gut derived peptides, glucagon-like peptides 1 and 2 (GLP-1 and GLP-2), are secreted following nutrient ingestion. GLP-1 and another gut peptide, glucose-dependent insulinotropic polypeptide (GIP) are collectively referred to as 'incretin' hormones, and play an important role in glucose homeostasis. Incretin secretion shares a complex interdependent relationship with both postprandial glycemia and the rate of gastric emptying. GLP-1 based therapies are now well established in the management of type 2 diabetes, while recent literature has suggested potential applications to treat obesity and protect against cardiovascular and neurological disease. The mechanism of action of GLP-2 is not well understood, but it shows promise as an intestinotropic agent.
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Affiliation(s)
- Chinmay S Marathe
- Discipline of Medicine, University of Adelaide, Royal Adelaide Hospital, Adelaide, Australia.
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117
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Marathe CS, Rayner CK, Jones KL, Horowitz M. Relationships between gastric emptying, postprandial glycemia, and incretin hormones. Diabetes Care 2013; 36:1396-405. [PMID: 23613599 PMCID: PMC3631884 DOI: 10.2337/dc12-1609] [Citation(s) in RCA: 223] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 11/15/2012] [Indexed: 02/05/2023]
Affiliation(s)
- Chinmay S. Marathe
- Discipline of Medicine, University of Adelaide, Royal Adelaide Hospital, Adelaide, Australia
- Centre of Clinical Research Excellence in Nutritional Physiology, Interventions and Outcomes, University of Adelaide, Adelaide, Australia
| | - Christopher K. Rayner
- Discipline of Medicine, University of Adelaide, Royal Adelaide Hospital, Adelaide, Australia
- Centre of Clinical Research Excellence in Nutritional Physiology, Interventions and Outcomes, University of Adelaide, Adelaide, Australia
| | - Karen L. Jones
- Discipline of Medicine, University of Adelaide, Royal Adelaide Hospital, Adelaide, Australia
- Centre of Clinical Research Excellence in Nutritional Physiology, Interventions and Outcomes, University of Adelaide, Adelaide, Australia
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Liou AP. DIGESTIVE PHYSIOLOGY OF THE PIG SYMPOSIUM: G protein-coupled receptors in nutrient chemosensation and gastrointestinal hormone secretion1. J Anim Sci 2013; 91:1946-56. [DOI: 10.2527/jas.2012-5910] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Affiliation(s)
- A. P. Liou
- Obesity, Metabolism & Nutrition Institute and Gastrointestinal Unit, Massachusetts General Hospital, Boston 02114
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119
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Sakurai M, Nakamura K, Miura K, Takamura T, Yoshita K, Nagasawa SY, Morikawa Y, Ishizaki M, Kido T, Naruse Y, Suwazono Y, Sasaki S, Nakagawa H. Sugar-sweetened beverage and diet soda consumption and the 7-year risk for type 2 diabetes mellitus in middle-aged Japanese men. Eur J Nutr 2013; 53:251-8. [PMID: 23575771 DOI: 10.1007/s00394-013-0523-9] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Accepted: 04/02/2013] [Indexed: 12/17/2022]
Abstract
PURPOSE This cohort study investigated the association between sugar-sweetened beverage (SSB) and diet soda consumption and the incidence of type 2 diabetes in Japanese men. METHODS The participants were 2,037 employees of a factory in Japan. We measured consumption of SSB and diet soda using a self-administered diet history questionnaire. The incidence of diabetes was determined in annual medical examinations over a 7-year period. Hazard ratios (HRs) with 95 % confidence intervals (CIs) for diabetes were estimated after adjusting for age, body mass index, family history, and dietary and other lifestyle factors. RESULTS During the study, 170 participants developed diabetes. The crude incidence rates (/1,000 person-years) across participants who were rare/never SSB consumers, <1 serving/week, ≥ 1 serving/week and <1 serving/day, and ≥ 1 serving/day were 15.5, 12.7, 14.9, and 17.4, respectively. The multivariate-adjusted HR compared to rare/never SSB consumers was 1.35 (95 % CI 0.80-2.27) for participants who consumed ≥ 1 serving/day SSB. Diet soda consumption was significantly associated with the incident risk of diabetes (P for trend = 0.013), and multivariate-adjusted HRs compared to rare/never diet soda consumers were 1.05 (0.62-1.78) and 1.70 (1.13-2.55), respectively, for participants who consumed <1 serving/week and ≥ 1 serving/week. CONCLUSIONS Consumption of diet soda was significantly associated with an increased risk for diabetes in Japanese men. Diet soda is not always effective at preventing type 2 diabetes even though it is a zero-calorie drink.
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Affiliation(s)
- M Sakurai
- Department of Epidemiology and Public Health, Kanazawa Medical University, 1-1 Daigaku, Uchinada, Ishikawa, 920-0293, Japan,
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120
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Johnston CS, Trier CM, Fleming KR. The effect of peanut and grain bar preloads on postmeal satiety, glycemia, and weight loss in healthy individuals: an acute and a chronic randomized intervention trial. Nutr J 2013; 12:35. [PMID: 23537225 PMCID: PMC3620575 DOI: 10.1186/1475-2891-12-35] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Accepted: 03/15/2013] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Peanut consumption favorably influences satiety. This study examined the acute effect of peanut versus grain bar preloads on postmeal satiety and glycemia in healthy adults and the long-term effect of these meal preloads on body mass in healthy overweight adults. METHODS In the acute crossover trial (n = 15; 28.4 ± 2.9 y; 23.1 ± 0.9 kg/m2), the preload (isoenergetic peanut or grain bar with water, or water alone) was followed after 60 min with ingestion of a standardized glycemic test meal. Satiety and blood glucose were assessed immediately prior to the preload and to the test meal, and for two hours postmeal at 30-min intervals. In the parallel-arm, randomized trial (n = 44; 40.5 ± 1.6 y, 31.8 ± 0.9 kg/m2), the peanut or grain bar preload was consumed one hour prior to the evening meal for eight weeks. Body mass was measured at 2-week intervals, and secondary endpoints included blood hemoglobin A1c and energy intake as assessed by 3-d diet records collected at pre-trial and trial weeks 1 and 8. RESULTS Satiety was elevated in the postprandial period following grain bar ingestion in comparison to peanut or water ingestion (p = 0.001, repeated-measures ANOVA). Blood glucose was elevated one hour after ingestion of the grain bar as compared to the peanut or water treatments; yet, total glycemia did not vary between treatments in the two hour postprandial period. In the 8-week trial, body mass was reduced for the grain bar versus peanut groups after eight weeks (-1.3 ± 0.4 kg versus -0.2 ± 0.3 kg, p = 0.033, analysis of covariance). Energy intake was reduced by 458 kcal/d in the first week of the trial for the grain bar group as compared to the peanut group (p = 0.118). Hemoglobin A1c changed significantly between groups during the trial (-0.25 ± 0.07% and -0.18 ± 0.12% for the grain bar and peanut groups respectively, p = 0.001). CONCLUSIONS Compared to an isoenergetic peanut preload, consumption of a grain bar preload one hour prior to a standardized meal significantly raised postmeal satiety. Moreover, consumption of the grain bar prior to the evening meal was associated with significant weight loss over time suggesting that glycemic carbohydrate ingestion prior to meals may be a weight management strategy.
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Affiliation(s)
- Carol S Johnston
- School of Nutrition and Health Promotion, Arizona State University, Phoenix, AZ 85004, USA.
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121
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Powell DR, Smith M, Greer J, Harris A, Zhao S, DaCosta C, Mseeh F, Shadoan MK, Sands A, Zambrowicz B, Ding ZM. LX4211 increases serum glucagon-like peptide 1 and peptide YY levels by reducing sodium/glucose cotransporter 1 (SGLT1)-mediated absorption of intestinal glucose. J Pharmacol Exp Ther 2013; 345:250-9. [PMID: 23487174 DOI: 10.1124/jpet.113.203364] [Citation(s) in RCA: 140] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
LX4211 [(2S,3R,4R,5S,6R)-2-(4-chloro-3-(4-ethoxybenzyl)phenyl)-6-(methylthio)tetrahydro-2H-pyran-3,4,5-triol], a dual sodium/glucose cotransporter 1 (SGLT1) and SGLT2 inhibitor, is thought to decrease both renal glucose reabsorption by inhibiting SGLT2 and intestinal glucose absorption by inhibiting SGLT1. In clinical trials in patients with type 2 diabetes mellitus (T2DM), LX4211 treatment improved glycemic control while increasing circulating levels of glucagon-like peptide 1 (GLP-1) and peptide YY (PYY). To better understand how LX4211 increases GLP-1 and PYY levels, we challenged SGLT1 knockout (-/-) mice, SGLT2-/- mice, and LX4211-treated mice with oral glucose. LX4211-treated mice and SGLT1-/- mice had increased levels of plasma GLP-1, plasma PYY, and intestinal glucose during the 6 hours after a glucose-containing meal, as reflected by area under the curve (AUC) values, whereas SGLT2-/- mice showed no response. LX4211-treated mice and SGLT1-/- mice also had increased GLP-1 AUC values, decreased glucose-dependent insulinotropic polypeptide (GIP) AUC values, and decreased blood glucose excursions during the 6 hours after a challenge with oral glucose alone. However, GLP-1 and GIP levels were not increased in LX4211-treated mice and were decreased in SGLT1-/- mice, 5 minutes after oral glucose, consistent with studies linking decreased intestinal SGLT1 activity with reduced GLP-1 and GIP levels 5 minutes after oral glucose. These data suggest that LX4211 reduces intestinal glucose absorption by inhibiting SGLT1, resulting in net increases in GLP-1 and PYY release and decreases in GIP release and blood glucose excursions. The ability to inhibit both intestinal SGLT1 and renal SGLT2 provides LX4211 with a novel dual mechanism of action for improving glycemic control in patients with T2DM.
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Affiliation(s)
- David R Powell
- Lexicon Pharmaceuticals, Inc., 8800 Technology Forest Place, The Woodlands, TX 77381, USA.
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122
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Abstract
CONTEXT Non-nutritive sweeteners can bind to sweet-taste receptors present not only in the oral cavity, but also on enteroendocrine and pancreatic islet cells. Thus, these sweeteners may have biological activity by eliciting or inhibiting hormone secretion. Because consumption of non-nutritive sweeteners is common in the United States, understanding the physiological effects of these substances is of interest and importance. EVIDENCE ACQUISITION A PubMed (1960-2012) search was performed to identify articles examining the effects of non-nutritive sweeteners on gastrointestinal physiology and hormone secretion. EVIDENCE SYNTHESIS The majority of in vitro studies showed that non-nutritive sweeteners can elicit secretion of gut hormones such as glucagon-like peptide 1 and glucose-dependent insulinotropic peptide in enteroendocrine or islet cells. In rodents, non-nutritive sweeteners increased the rate of intestinal glucose absorption, but did not alter gut hormone secretion in the absence of glucose. Most studies in humans have not detected effects of non-nutritive sweeteners on gut hormones or glucose absorption. Of eight human studies, one showed increased glucose-stimulated glucagon-like peptide 1 secretion after diet soda consumption, and one showed decreased glucagon secretion after stevia ingestion. CONCLUSIONS In humans, few studies have examined the hormonal effects of non-nutritive sweeteners, and inconsistent results have been reported, with the majority not recapitulating in vitro data. Further research is needed to determine whether non-nutritive sweeteners have physiologically significant biological activity in humans.
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Affiliation(s)
- Rebecca J Brown
- National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892-1645, USA.
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123
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Swithers SE, Laboy AF, Clark K, Cooper S, Davidson TL. Experience with the high-intensity sweetener saccharin impairs glucose homeostasis and GLP-1 release in rats. Behav Brain Res 2012; 233:1-14. [PMID: 22561130 PMCID: PMC3378816 DOI: 10.1016/j.bbr.2012.04.024] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 04/09/2012] [Accepted: 04/15/2012] [Indexed: 12/26/2022]
Abstract
Previous work from our lab has demonstrated that experience with high-intensity sweeteners in rats leads to increased food intake, body weight gain and adiposity, along with diminished caloric compensation and decreased thermic effect of food. These changes may occur as a result of interfering with learned relations between the sweet taste of food and the caloric or nutritive consequences of consuming those foods. The present experiments determined whether experience with the high-intensity sweetener saccharin versus the caloric sweetener glucose affected blood glucose homeostasis. The results demonstrated that during oral glucose tolerance tests, blood glucose levels were more elevated in animals that had previously consumed the saccharin-sweetened supplements. In contrast, during glucose tolerance tests when a glucose solution was delivered directly into the stomach, no differences in blood glucose levels between the groups were observed. Differences in oral glucose tolerance responses were not accompanied by differences in insulin release; insulin release was similar in animals previously exposed to saccharin and those previously exposed to glucose. However, release of GLP-1 in response to an oral glucose tolerance test, but not to glucose tolerance tests delivered by gavage, was significantly lower in saccharin-exposed animals compared to glucose-exposed animals. Differences in both blood glucose and GLP-1 release in saccharin animals were rapid and transient, and suggest that one mechanism by which exposure to high-intensity sweeteners that interfere with a predictive relation between sweet tastes and calories may impair energy balance is by suppressing GLP-1 release, which could alter glucose homeostasis and reduce satiety.
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Affiliation(s)
- Susan E Swithers
- Department of Psychological Sciences, Purdue University, West Lafayette, IN 47907, USA.
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