Clinical trial NCT01804738: Investigating Inter-individual Variability in Glycemic and Insulin Responses
Official title: Investigating Inter-individual Variability in Glycemic and Insulin Responses
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Hyperglycemia
Insulin Sensitivity
Keywords: Ethnic differences
Inter-individual variability
Glycemic response
Insulin response
Mastication
Salivary alpha-amylase
Gastric emptying
Metagenome
Lead sponsor: Institute for Human Development and Potential (IHDP), Singapore
Sponsor class: OTHER
First posted: 2013-03-05
Enrollment: 75
Sex: MALE
Minimum age (years): 21
Maximum age (years): 40
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: BASIC_SCIENCE

Brief summary: 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: 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.

Eligibility criteria: 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

Primary outcomes:
measure: Postprandial glycemic and insulin responses
timeFrame: Every 15 mins in the first hour and every 30 mins for the next 2 hours after food consumption
Secondary outcomes:
measure: Physiological digestive functions
timeFrame: Up to 5 hours
Other outcomes:
measure: Glycemic index values
timeFrame: 180 mins
Locations:
city: Singapore
country: Singapore
facility: Clinical Nutrition Research Centre
Study officials:
affiliation: Institute for Human Development and Potential (IHDP), Singapore
name: Yung S Lee, A/Prof
role: PRINCIPAL_INVESTIGATOR
References:
citation: 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.
citation: 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.
citation: 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.