The Effect of Lactisole on the Responses to Glucose Solution

Study Overview
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Brief Summary
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The purpose of the study is to determine whether the sweet taste receptors in the gut are involved in sensing sweet substances and controlling appetite and the amount we eat. Lactisole is a substance commonly used in food products to reduce the perceived sweetness of certain sugars and sweeteners. The aim of this study is to investigate whether the responses to a glucose solution, intragastrically administered to healthy male and female volunteers, is affected by the presence of lactisole in the gut. Understanding the mechanisms by which nutrients are initially detected in the gut and how they influence food intake is critical to the development of novel food products that could reduce food consumption.

Detailed Description
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Obesity is epidemically prevalent and a major risk factor for chronic diseases making it fundamental to understand the pathways controlling food intake. During the course of a meal and afterwards the gut and brain communicate to control how full the eater feels and thus control the amount of food eaten. The information relayed from the gut to the brain regarding ingested nutrients is of increasing importance and understanding the mechanisms by which nutrient molecules are initially detected in the gut and how they signal to the brain to influence food intake is critical to the development of novel food products that could induce fullness and reduce food consumption. Increasing our understanding of how nutrients are sensed in the gut and how this may influence subsequent food intake provides promising targets for obesity prevention and treatment. Recent discoveries have shown that sweet taste receptors similar to those located in the tongue are present in the gut. It is suggested that theses receptors are involved in the way nutrients are sensed and may play an important role in appetite control and food intake.

Official Title
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Study of the Effect of Lactisole on the Responses to Intragastric Glucose Solution

Conditions
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Blood Glucose, Appetite, Therapeutic Uses, Hormones

Intervention / Treatment
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* Other: Lactisole
* Dietary Supplement: Lactisole
* Dietary Supplement: Lactisole
* Dietary Supplement: Lactisole


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Aged between 18-45 years BMI between 18-25kg/m2 General good health Exclusion Criteria: Underweight or Overweight (Body Mass Index <19 or >25 kg.m-2) Females who are pregnant or breastfeeding Currently taking medication (except females taking oral contraceptive) Smokers Currently dieting or have experienced a weight change +/- 3kg in past 6 months Metabolic disorders (eg. Type 2 diabetes) History of gastrointestinal disorders Participation in other research in past 3 months

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Lactisole-Glucose<br> | Other: Lactisole<br>* A pre-infusion of lactisole solution (0.25mg/ml) is administered as a bolus (1ml/kg bodyweight)via intragastric tube. After 15 minutes a 1M glucose solution is administered as a bolus via intragastric tube.<br>|
| Active Comparator: Lactisole-water<br> | Dietary Supplement: Lactisole<br>* A pre-infusion of lactisole solution (0.25mg/ml)is administered as a bolus (1ml/kg body weight) via intragastric tube. After 15 minutes tap water will be administered as a bolus via the intragastric tube.<br>|
| Placebo Comparator: Water-Glcuose<br> | Dietary Supplement: Lactisole<br>* A pre-infusion of tap water(is administered as a bolus (1ml/kg bodyweight)via intragastric tube. After 15 minutes a 1M glucose solution is administered as a bolus via intragastric tube.<br>|
| Placebo Comparator: Water-Water<br> | Dietary Supplement: Lactisole<br>* A pre-infusion of tap water is administered as a bolus (1ml/kg bodyweight)via intragastric tube. After 15 minutes tap water is administered as a bolus via intragastric tube.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Blood glucose |  | Blood samples will be collected at baseline and 5, 15 and 30 minute intervals until 150 minutes after the glucose infusion | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Subjective appetite ratings | Participants will be asked to complete visual analogue scale questionnaire (VAS) up to a total of 6 times for the duration of each study | 30 minute intervals | 
| Gastric emptying rate | In order to assess gastric emptying, a stable isotope of carbon, in the form of 13Csodium acetate will be added to the test meal. This is absorbed only once it has passed through the stomach into the duodenum. It is then metabolised and exhaled in the breath as 13Clabelled carbon dioxide (CO2) where it can be measured. | Breath samples are collected at 5, 15 and 30 minute intervals up to a total of 10 times until 150 minutes | 
| Energy intake | Energy intake will be assessed by an ad libitum test meal provided at the end of each study and food diaries completed for the remainder of the day |  | 
| Gut hormones | Blood samples will be processed to examine hormone levels of GLP-1, PYY, and insulin. | Blood samples will be collected at baseline, 5, 15 and 30 minute intervals until 150 minutes after glucose infusion. |