Investigating Inter-individual Variability in Glycemic and Insulin Responses

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

Study Overview

• Status: Completed
• Conditions: Hyperglycemia; Insulin Sensitivity
• Intervention / Treatment: Other: Jasmine rice; Other: Parboiled basmati rice

Detailed Description

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.

• Study Type: Interventional
• Enrollment (Actual): 75
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Singapore
  • Singapore, Singapore, 117599
    • Clinical Nutrition Research Centre

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 21 years to 40 years (ADULT)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: Male

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: BASIC_SCIENCE
• Allocation: RANDOMIZED
• Interventional Model: CROSSOVER
• Masking: NONE

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
NO_INTERVENTION: Glucose; Glucose anhydrous 50g dissolved in 250ml water
ACTIVE_COMPARATOR: Jasmine rice; 50g available carbohydrate portion	Other: Jasmine rice; Standardised rice:cooking liquid ratio for 50g available carbohydrate portion
ACTIVE_COMPARATOR: Parboiled basmati rice; 50g available carbohydrate portion	Other: Parboiled basmati rice; Standardised rice:cooking liquid for 50g available carbohydrate portion; Other Names: Dreamrice

What is the study measuring?

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

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Glycemic index values	Derivation of the glycemic index values of foods using postprandial glycemic response to reference food and test foods.	180 mins

Collaborators and Investigators

• Sponsor: Singapore Institute for Clinical Sciences
• Investigators: Principal Investigator: Yung S Lee, A/Prof, Singapore Institute for Clinical Sciences

Publications and helpful links

General Publications

• Tan VM, Ooi DS, Kapur J, Wu T, Chan YH, Henry CJ, Lee YS. The role of digestive factors in determining glycemic response in a multiethnic Asian population. Eur J Nutr. 2016 Jun;55(4):1573-81. doi: 10.1007/s00394-015-0976-0. Epub 2015 Jul 10.
• Tan VM, Wu T, Henry CJ, Lee YS. Glycaemic and insulin responses, glycaemic index and insulinaemic index values of rice between three Asian ethnic groups. Br J Nutr. 2015 Apr 28;113(8):1228-36. doi: 10.1017/S0007114515000586. Epub 2015 Mar 19.
• Ooi DS, Tan VM, Ong SG, Chan YH, Heng CK, Lee YS. Differences in AMY1 Gene Copy Numbers Derived from Blood, Buccal Cells and Saliva Using Quantitative and Droplet Digital PCR Methods: Flagging the Pitfall. PLoS One. 2017 Jan 26;12(1):e0170767. doi: 10.1371/journal.pone.0170767. eCollection 2017.

Study record dates

Study Major Dates

• Study Start (ACTUAL): March 1, 2013
• Primary Completion (ACTUAL): June 1, 2014
• Study Completion (ACTUAL): June 1, 2014

Study Registration Dates

• First Submitted: March 4, 2013
• First Submitted That Met QC Criteria: March 4, 2013
• First Posted (ESTIMATE): March 5, 2013

Study Record Updates

• Last Update Posted (ACTUAL): March 14, 2019
• Last Update Submitted That Met QC Criteria: March 12, 2019
• Last Verified: March 1, 2019

More Information

Terms related to this study

• Keywords: Gastric emptying; Glycemic response; Insulin response; Metagenome; Mastication; Ethnic differences; Inter-individual variability; Salivary alpha-amylase
• Additional Relevant MeSH Terms: Glucose Metabolism Disorders; Metabolic Diseases; Hyperinsulinism; Hyperglycemia; Insulin Resistance
• Other Study ID Numbers: 2012/01149