Adiponectin : An indicator for metabolic syndrome

Our research group would like to thank all subjects who took part in current study. The project was financially supported by the Iran University of Medical Sciences. (93-02-27-24976)Peer reviewedPublisher PD

Effects of Bitter Substances on Energy Intake and Blood Glucose, and Associated Gastrointestinal Functions, in Healthy Humans

The studies in this thesis investigated whether specific bitter compounds, administered intraduodenally or intragastrically, reduce postprandial blood glucose and/or energy intake in healthy humans, by modulating GI functions, e.g. gut hormones, gut motility and gastric emptying. The key findings of the studies are: 1. Slow intraduodenal infusion of quinine, providing doses of 37.5, 75 and 225 mg, over 60 min, did not affect antropyloroduodenal motility, plasma CCK or energy intake, possibly because the delivery rate was insufficient to activate duodenal bitter taste receptors (Chapter 2). 2. Intragastric bolus administration of quinine, at doses of 275 and 600 mg, slightly stimulated insulin, and, in response to a mixed-nutrient drink, consumed 30 min later, lowered plasma glucose, associated with markedly increased insulin and modest increases in glucagon and GLP-1, but did not slow gastric emptying, suggesting that, in this study paradigm, postprandial blood glucose lowering was primarily due to insulin (Chapter 3). 3. Both intragastric and intraduodenal administration of quinine (600 mg), administered 60 min or 30 min, respectively, before consumption of a mixed-nutrient drink, markedly stimulated C-peptide and reduced plasma glucose, both alone and following the drink, and slowed gastric emptying, with no difference between the routes of administration. The data suggest that, intragastric quinine, when allowed sufficient time to interact with intestinal bitter-taste receptors, reduces blood glucose, by stimulating insulin and slowing gastric emptying, comparably with intraduodenal quinine (Chapter 4). 4. Intraduodenal administration of a bitter extract from hops flowers, Humulus lupulus L., only had a modest, and transient, effect to stimulate pyloric pressure, and a delayed effect to stimulate PYY (~ 60 min post-administration), but did not affect antral or duodenal pressures, CCK or energy intake. While the intragastric study part needs to be completed, it appears that intragastric delivery of hops extract may have a more potent, and persistent, effect to stimulate pyloric pressure than intraduodenal delivery. While these findings may suggest that bitter hops extract, in contrast to quinine, may have a greater effect on gastric bitter receptors, the study will need to be completed to draw more definitive conclusions (Chapter 5). In conclusion, the research presented in this thesis has established that bitter compounds, including quinine and hops extract, vary in their potency, and effects, on GI functions, i.e. secretion of gut hormones, modulation of gut motility and/or gastric emptying, that are associated with regulation of energy intake and/or blood glucose. Quinine had potent glucose-lowering effects, mediated by both gastric emptying and stimulation of glucoregulatory hormones, including insulin, while the role of GLP-1 is less clear. In contrast, the effects of hops extract remain less clear. Further research is warranted to investigate the suitability of these, and other, bitter compounds as novel and effective management or treatment strategies for type 2 diabetes and/or obesity.Thesis (Ph.D.) -- University of Adelaide, Adelaide Medical School, 202

Gastrointestinal Sensing of Meal-Related Signals in Humans, and Dysregulations in Eating-Related Disorders

The upper gastrointestinal (GI) tract plays a critical role in sensing the arrival of a meal, including its volume as well as nutrient and non-nutrient contents. The presence of the meal in the stomach generates a mechanical distension signal, and, as gastric emptying progresses, nutrients increasingly interact with receptors on enteroendocrine cells, triggering the release of gut hormones, with lipid and protein being particularly potent. Collectively, these signals are transmitted to the brain to regulate appetite and energy intake, or in a feedback loop relayed back to the upper GI tract to further adjust GI functions, including gastric emptying. The research in this area to date has provided important insights into how sensing of intraluminal meal-related stimuli acutely regulates appetite and energy intake in humans. However, disturbances in the detection of these stimuli have been described in a number of eating-related disorders. This paper will review the GI sensing of meal-related stimuli and the relationship with appetite and energy intake, and examine changes in GI responses to luminal stimuli in obesity, functional dyspepsia and anorexia of ageing, as examples of eating-related disorders. A much better understanding of the mechanisms underlying these dysregulations is still required to assist in the development of effective management and treatment strategies in the future

Effects of Bitter Substances on GI Function, Energy Intake and Glycaemia-Do Preclinical Findings Translate to Outcomes in Humans?

Bitter substances are contained in many plants, are often toxic and can be present in spoiled food. Thus, the capacity to detect bitter taste has classically been viewed to have evolved primarily to signal the presence of toxins and thereby avoid their consumption. The recognition, based on preclinical studies (i.e., studies in cell cultures or experimental animals), that bitter substances may have potent effects to stimulate the secretion of gastrointestinal (GI) hormones and modulate gut motility, via activation of bitter taste receptors located in the GI tract, reduce food intake and lower postprandial blood glucose, has sparked considerable interest in their potential use in the management or prevention of obesity and/or type 2 diabetes. However, it remains to be established whether findings from preclinical studies can be translated to health outcomes, including weight loss and improved long-term glycaemic control. This review examines information relating to the effects of bitter substances on the secretion of key gut hormones, gastric motility, food intake and blood glucose in preclinical studies, as well as the evidence from clinical studies, as to whether findings from animal studies translate to humans. Finally, the evidence that bitter substances have the capacity to reduce body weight and/or improve glycaemic control in obesity and/or type 2 diabetes, and potentially represent a novel strategy for the management, or prevention, of obesity and type 2 diabetes, is explored

Association between Dietary Macronutrient Intake and Symptoms in Uninvestigated Dyspepsia: Evidence from a Population-Based, Cross-Sectional Study

(1) Background: Limited evidence from laboratory-based studies suggests that specific dietary macronutrients, particularly fat, can induce dyspeptic symptoms. Through a population-based study, we investigated the relationship between dietary macronutrients and dyspeptic symptoms and sought to determine macronutrient intake thresholds to predict or prevent dyspepsia and reduce symptoms in patients with dyspepsia. (2) Methods: A total of 4763 Iranian people were enrolled in this population-based, cross-sectional study. Uninvestigated dyspepsia (UD) and its symptoms, including postprandial fullness, early satiation, and epigastric pain, were evaluated using a modified Persian version of the Rome III criteria. The dietary intakes of participants were evaluated using a validated food–frequency questionnaire. Receiver operating characteristic (ROC) curve analysis was used to calculate threshold intakes of dietary macronutrients to prevent UD in the general population. The analysis was then repeated in those with UD to calculate intake thresholds for reducing UD symptoms. (3) Results: Early satiation occurred in 6.3% (n = 302), postprandial fullness in 8.0% (n = 384) and epigastric pain in 7.8% (n = 371) of participants. The prevalence of UD was 15.2%. Compared with individuals without UD, those with UD had a lower intake of carbohydrates (48.2% vs. 49.1%) and a higher intake of fats (38.3% vs. 37.4%), while protein and energy intakes did not differ. Higher dietary fat and protein intakes were associated with a higher prevalence of postprandial fullness and epigastric pain, respectively. Macronutrient intakes to predict UD in the general population were <49% of energy from carbohydrates, >14.7% from protein, and >37.7% from fats. Carbohydrate, protein, and fat intakes to prevent symptoms among those with UD were calculated to be >48.2%, <14.6%, and <38.6%, respectively. (4) Conclusion: Higher carbohydrate intake and lower fat or protein intakes were associated with a lower likelihood of UD. Prospective studies carefully manipulating dietary macronutrient composition are warranted to investigate the value of dietary changes to improve symptoms in people with UD

The effect of saffron (Crocus sativus L.) hydro-alcoholic extract on liver and renal functions in type 2 diabetic patients: A double-blinded randomized and placebo control trial

Background and aim: Uncontrolled diabetes causes liver and renal dysfunctions. Since, saffron may improve diabetes control and indicate renal and liver protection, this study purposed to illustrate for the first time the effects of saffron extract on some liver and renal functional parameters among diabetic patients. Materials and methods: In this double-blind clinical trial, 54 type 2 diabetic patients were randomly recruited to consume either 15 mg saffron extract (n = 27) or placebo capsules (n = 27) twice a day for 8 weeks. Alkaline phosphatase, aspartate and alanine amino transferase, uric acid, blood urea nitrogen, and creatinine of the patients as well as their physical activity, dietary intakes, anthropometric measures and blood pressure were measured. Data were analyzed by SPSS.18 software. Results: Uric acid and blood urea nitrogen were significantly decreased in the saffron group (P < 0.05), however, there were no significant differences between the two groups at the end of the study (p = 0.29 and 0.14, respectively). Moreover, changes in other profiles, including liver enzymes, were not statistically significant in the two groups. Also, no significant changes in blood pressure, dietary intakes, and physical activity were seen among the two groups. Conclusion: Saffron hydro-alcoholic extract did not considerably improve renal and liver functions in T2DM patients in an 8-week randomized clinical trials. The results deserved further investigations with more accurate methods to confirm