The Impact of Low Glycaemic Index (GI) Biscuits on Postprandial Glycaemia Using the Continuous Glucose Monitoring System (CGMS™) (Biscuit Study (BIS) Study)
Condition: Diabetes Mellitus, Type 2; Diabetes
MeSH terms: Diabetes Mellitus; Diabetes Mellitus, Type 2
Study type: Interventional

Summary: 
      To investigate whether low glycaemic index (GI) biscuits have the greatest impact on the
      post-meal glucose response and on the overall 24 hour blood glucose control, using the
      continuous glucose monitoring system (CGMS™)
    

Detailed description: 
      The study was a randomized, non-blinded, crossover design. Randomization conducted using
      www.randomizer.org. Each participant came for two test sessions (each of 3 days- Days 0, 1
      and 2) with each session separated by at least three days (to avoid crossover effects). Test
      foods: The foods were Control and Test [Low glycemic index (GI)] biscuits. The foods will
      vary in macronutrient, micronutrients and fibre contents. Screening session: Potential
      participants attend a first session for consenting and screening procedures. Subjects will be
      at the centre for the study between 8:00-9:00am, with screening session lasting approximately
      1 hour. Subjects will have to come following a 10-12 hour overnight fast each day.
      Fingerprick blood sample (5μl) is required for the screening session (to establish fasting
      glucose concentration). Screening questionnaire: The screening questionnaire will include
      contact information, demographic, general health details, and physical activity level. This
      information will be used to determine whether the participant is eligible for the study, as
      well as to check for any possible confounders that may influence the study outcomes.
      Anthropometric measurements: Body weight and body composition will be measured using
      bioelectrical impedance analysis (Tanita scale). Height will be measured using a stadiometer
      in order to calculate participants' BMI. Waist circumference will be measured at the minimum
      circumference between the iliac crest and the rib cage. Hip circumference will be measured at
      the maximum protuberance of the buttocks. Biceps and triceps skinfold measurements will also
      be taken. Blood pressure will also be measured. Blood pressure: Blood pressure will be
      measured using an Omron blood pressure monitor (Model HEM-907) at baseline. Participants will
      be seated for five minutes before blood pressure is measured. Measurements will be taken in
      duplicate and the averaged results will be recorded. (approximately 1 teaspoon or 5 ml) will
      be collected from subject via passive drooling (only once during). Start of test session (Day
      0-Day 2) Day 0 If subject is eligible, subjects will be enrolled into the study. Subject will
      undergo the insertion of the Continuous Glucose Monitoring System (CGMS™) sensor the day
      before the test day (Day 0) to allow for the monitor to stabilize overnight. Medtronic's
      iPro2 Professional CGMS, designed to gain more complete insights into the glycaemic profiles
      of a person. The CGMS sensor will be inserted into the adipose tissue in the abdominal area
      by trained researchers and nurses. Subjects will have to wait in the laboratory for 1 hour
      after insertion for the sensor to be stabilized. After 1 hour the inserted CGMS sensor will
      be calibrated against a manual finger-prick blood glucose sample (5 μL, a small drop). Manual
      calibration using finger-prick blood samples will need to be carried out before every meal
      and before bed in the night (5 μL each for before dinner and before sleeping). The
      calibrations before dinner and bed will have to be carried out the subjects at home.
      Therefore, the subjects will be provided with a finger-prick blood glucose test kit to take
      home and instructed on how to correctly use it and measure blood glucose values. Calibration
      finger pricks will be made using disposable individual lancets. This may cause minimal
      discomfort. The volume of blood taken each time will be 5 μL (a small drop). For Day 0,
      subjects will be provided a standard dinner meal to be consumed at home at 7pm. Afterwhich,
      they will be asked to not eat and drink anything except water after 10:30 pm. They will also
      be instructed to arrive at the CNRC the following morning in an overnight fasted state. On
      the evenings before the test sessions, subject will be reminded to have no strenuous physical
      activities and no consumption of alcoholic beverages. Day 1 On the test Day 1, participants
      will be asked to attend the testing sessions after an overnight fast of ten to twelve hours,
      and arrive between 8:00-9:00am, with each session lasting approximately 4 hours. One fasting
      blood sample will be collected by fingerprick for calibration of the CGMS glucose meter (5
      μL, a small drop). Then, an indwelling catheter will be inserted into a vein in the forearm.
      Subsequently, a blood sample will be taken from a cannula to measure baseline values.
      Immediately after that, participants will be served a test breakfast, where they will be
      asked to consume within 15 minutes. Following the test breakfast meal, further blood samples
      will be taken (from the cannula) for the next 15, 30, 45, 60, 90, 120, 150, 180 minutes. The
      blood samples collected at each timepoint will be measured for insulin and metabolic
      biomarkers related to the intake of the test meal ingredients. The amount of blood that will
      be collected at every time point will be about 1.2 teaspoon of blood (approximately 6 ml),
      the accumulative amount per test session will not be more than 11 teaspoons of blood
      (approximately 55 ml), and the accumulative amount for the entire study duration will not be
      more than 22 teaspoons of blood (approximately 110 ml), by cannula. For the fingerprick
      calibration, 5 μL is taken after insertion of sensor, before each meal and before sleeping.
      So a total of 9 fingerpricks will be taken for one test session. Therefore, a total of 18
      fingerpricks for the entire two sessions. (approximately 90 μL equivalent to approximately
      1/5 of a teaspoon). A standard lunch will then be served and afterwhich the cannula is
      removed. Subjects will take a fingerprick blood glucose (5 μL, a small drop) for calibration
      of the CGMS before their standard lunch meal. Subjects are to consume the entire lunch meal
      in 15 minutes. After lunch, participants will be provided with their snack and dinner meal to
      be consumed at home and they will leave the research facility. Before snack, dinner and
      before sleeping, participants are to take their own fingerprick blood glucose for calibration
      of the CGMS.Day 2 Participants will return the following day, Day 2, between 8:00-9:00am.
      Participants will have the CGMS sensor removed. A final fingerprick (5 μL, a small drop) for
      calibration purposes will be done 15 minutes before removal of the sensor. This marks the end
      of one session and participant will return for the next session after 3 days of washout
      period. Participants attend a total of about 15 hours for two sessions (including one
      screening visit lasting around 1 hour). Participants will spend approximately 1 hour for
      screening session, 1 hour for Day 0, 4 hours for Day 1 and about half hour on Day 2. This
      will repeat for the next session. All test and standard meals in the research facility will
      be served with 250ml of water. All the study diets will be prepared in the CNRC food
      preparation kitchen and will use locally sourced ingredients and food purchased from local
      supermarkets and food distributors.
    

Intervention name(s): Biscuit 1 Control; Biscuit 2 Test
Intervention type(s): Other; Other
Intervention description(s): Consumption of control biscuit of a higher glycaemic index at one session during breakfast and afternoon snack; Consumption of test biscuit of a lower glycaemic index at one session during breakfast and afternoon snack
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Other