Study to Determine Ethnic Differences in the Glycaemic Response to Nutritional Formula Drinks
Condition: Diabetes; Impaired Glucose Tolerence
Study type: Interventional

Summary: 
      Nutritional formula drinks are widely consumed in Asia especially by those having chronic
      illnesses such as diabetes. Therefore, gauging the impact of nutritional formulas on blood
      glucose levels is very important. Asia is home to three predominant ethnic groups- Chinese,
      Malay and Indians. It is still unknown if the blood glucose response to nutritional formulas
      differs between ethnic groups. Therefore the aim of this study is to observe if there are
      ethnic differences in the blood glucose response to nutritional formula drinks.
    

Detailed description: 
      Nutritional formulas are commonly consumed by individuals both to supplement their food
      intake and as total meal replacers. Consumption rates of nutritional formulas are increasing
      also in Asia. Very little is known about differences in the glycaemic response to nutritional
      formulas between different ethnic groups. The aim of the current study is to determine the
      glycaemic response (GR) and glycaemic index (GI) to three nutrition formulas in Chinese,
      Indian and Malay subjects.

      The study will have a randomised, non-blind, between-subjects, crossover design. The subjects
      will return for six test sessions. At three random sessions subjects will test the reference
      food and on the remaining three sessions they will consume the test foods (Diasip, Isocal,
      Protinex). The first test session will be a glucose test session (for subjects requiring
      glucose tests). The reference food will be anhydrous glucose (50 g) dissolved in 250 ml of
      water. The test foods will be portions of the nutritional formulas containing 50 g of
      available carbohydrates. Subjects who have previously taken part in GI studies at the CNRC
      and who have already completed three reference glucose tests will have to complete only the
      three test food sessions. However, they may be asked to do one, two or all three of the
      glucose tests if their previous test results are old (> 3 months) or are not within the
      required precision (CV <30%). This aspect will be at the discretion of the investigator and
      communicated to the participant at the time of briefing (before consenting).

      The primary measurement in the study will be the glycaemic response. This will be measured
      using finger-prick blood samples. The fingers in the non-dominant hand will be used. To
      encourage blood flow the hand will be warmed using warm water or a hot towel beforehand if
      required. The finger will then be disinfected using a sterile wipe. Blood will be obtained by
      finger prick using a single-use lancing device. To minimise plasma dilution fingertips will
      not be squeezed to extract blood but gently massaged starting from the base of the hand
      moving towards the tips. The first two drops of expressed blood will be discarded and the
      next drop (5 μL) will be used for testing. Blood glucose in the sample will be measured using
      the HemoCue® 201+ Glucose analyser (HemoCue Ltd, Dronfield, UK).

      The participants will arrive at the laboratory between 8:30-9 am following a 10 hour
      overnight fast. They will be instructed not to partake in intense level sports and avoid
      alcohol consumption on the evening prior to a test session. Following a 10 minute rest two
      blood samples will be obtained five minutes apart for determining baseline blood glucose
      levels. If the two baseline blood glucose values are far apart a further 1-2 blood samples
      may be taken until two stable values are obtained. The study session will be terminated if
      stable values cannot be obtained or if baseline blood glucose levels are above 6 mmol/L.
      After obtaining acceptable baseline blood glucose values they will be given either the
      standard or test food to consume. They will be asked to consume the drink at a comfortable
      pace within 10 minutes. Further blood samples will be obtained at 15, 30, 45, 60, 90, 120,
      150 and 180 minutes for blood glucose measurements. Mandatory sampling will be carried out up
      to 120 minutes. If the blood glucose level has not reached baseline levels by the end of 120
      minutes further samples may be taken at 150 and 180 minutes. During the entire testing period
      the participants will be instructed to remain rested and in the laboratory.
    

Intervention name(s): Liquid-based Nutritional Formulae and liquid glucose
Intervention type(s): Dietary Supplement
Other intervention name(s): Diasip; Protinex; Isocal; liquid glucose
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: Glycaemic response; Glycaemic Index; Nutritional formula; Asia; Ethnic differences; Chinese; Malay; Indian