Investigating Inter-individual Variability in Glycemic and Insulin Responses

Study Overview
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Brief Summary
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This study aims to test the following hypothesis in healthy lean young men: There are differences in glycemic response (GR) and insulin response (IR) between Chinese, Malay and Asian-Indian There are differences in GI values to the same food between ethnic groups There are ethnic differences postprandial GR and IR for high vs low GI foods Mastication, salivary amylase activity, gastric emptying rate and gut microbiota composition influences inter-individual glycemic and insulinemic variability Ethnic differences in mastication, salivary amylase activity, gastric emptying rate and gut microbiota composition determines the inter-ethnic glycemic and insulinemic variability

Detailed Description
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There is extensive evidence that numerous biological digestive factors varies between individuals and influence postprandial glycemic response (GR) and insulin response (IR), which are well established risk factors that precipitate the development of Type 2 diabetes mellitus (T2DM). However, no study to date has measured and compared physiological parameters such as mastication, salivary amylase activity, gastric emptying rates and gut microbiota in a multi-ethnic Asian population, with varying prevalence of obesity and T2DM. The aim of this study is to investigate ethnic differences in GR and IR as well as the GI values of foods. Additionally, we aim to examine how physiological digestive factors contribute to inter-ethnic and inter-individual variability in GR and IR. The study outcomes can potentially explain, in part, the varying susceptibility to obesity, T2DM and DM control between Chinese, Malays and Asian-Indians in Singapore, as reflected by the differences in prevalence of obesity, T2DM and DM control among the three local ethnic groups.

Official Title
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Investigating Inter-individual Variability in Glycemic and Insulin Responses

Conditions
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Hyperglycemia, Insulin Sensitivity

Intervention / Treatment
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* Other: Jasmine rice
* Other: Parboiled basmati rice


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Be willing and able to comply with study procedures and given written informed consent Chinese/Malay/Indian males, aged 21-40 years old Body mass index (BMI) between 18.5 - 24.9 kg/m2 Fasting blood glucose between 4 - 6 mmol/L Sedentary adults, with <1 episode of exercise per week Not have a history of food allergies or food intolerances Be a non-smoker Drinks less than 3 units of alcohol per day Not taking antibiotics for the past 3 weeks Exclusion Criteria: Subjects with known chronic diseases, including diabetes, untreated hypertension, renal impairment, gastrointestinal problems, and other significant medical conditions BMI <18.5 kg/m2 or >25 kg/m2 Fasting blood glucose ≥7.0mmol/l Alcohol consumption >3 drinks / day Use of medications known to affect glucose metabolism Recent changes in weight of >5% over the past 3 months Significant changes in diet over the past 3 months History of eating disorders or irregular eating habits Taking antibiotics medications over the past 3 weeks

Ages Eligible for Study
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Minimum Age: 21 Years
Maximum Age: 40 Years

Sexes Eligible for Study
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Male

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: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| No Intervention: Glucose<br>Glucose anhydrous 50g dissolved in 250ml water | |
| Active Comparator: Jasmine rice<br>50g available carbohydrate portion | Other: Jasmine rice<br>* Standardised rice:cooking liquid ratio for 50g available carbohydrate portion<br>|
| Active Comparator: Parboiled basmati rice<br>50g available carbohydrate portion | Other: Parboiled basmati rice<br>* Standardised rice:cooking liquid for 50g available carbohydrate portion<br>* Other names: Dreamrice;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Postprandial glycemic and insulin responses | Capillary bloods will be obtained using finger-pricks | Every 15 mins in the first hour and every 30 mins for the next 2 hours after food consumption | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Physiological digestive functions | They include: measurement of mastication rate, salivary amylase activity, gastric emptying rate and gut microbiota composition | Up to 5 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Glycemic response, Insulin response, Mastication, Salivary alpha-amylase, Gastric emptying, Metagenome, Ethnic differences, Inter-individual variability