None listed
Conditions
Brief summary
Kibbled grain breads are likely to have a lower glycaemic effect than white breads because they have a number of features associated with reduced blood glucose response such as dietary fibre, and plant structure that limits starch digestibility. The aim of the study is to establish the effect of two types of kibbled grain breads on blood glucose relative to the effect of a white bread reference. This study also determines the effect of intact grain structure on the postprandial blood glucose responses to bread with or without chewing. This will give us a measure of the in vivo relative glycaemic potency of the two bread types, which have been selected for possessing low glycaemic potency when estimated using validated in vitro methods. Standard glycaemic response testing protocols will be used. After an overnight fast, participants will consume a different one of each of nine bread samples delivering 40 g available carbohydrate, on nine occasions, each a week apart. The breads will be: 1) White bread, (2) Soy and purple wheat kibbled grain bread and (3) Purple wheat kibbled grain bread, each in three forms:(1) As normally masticated, (2) swallowed without chewing, and (3) swallowed after homogenizing, giving the 9 samples. A randomised repeated measures design will be used in this study. Blood glucose will be measured by finger prick sampling at 8-time points over a two hour period. Two blood samples will be taken at baseline and single blood samples over the 2 hour postprandial period. Blood glucose concentrations will be measured with a HemoCue® blood glucose meter, and changes from baseline will be plotted against time to obtain blood glucose response curves. These curves will be analysed to obtain information on the area under the curve and the distribution of the area to reveal the glycaemic impact characteristics of the bread samples.
Interventions
A randomised repeated measures design will be used in which each subject receives all diets in a random order.
The test foods will be as follows:
1. White bread: 105 g (Reference) plus 188 ml water (Treatment: Chew)
2. Soy-purple wheat kibbled bread: 163 g plus 150 ml water (Treatment: Chew)
3. Purple wheat kibbled bread: 125 g plus 171 ml water (Treatment: Chew)
4. White bread: 105 g (Reference) homogenized with 188 ml water (Treatment: Swallow)
5. Soy-purple wheat kibbled bread: 163 g homogen
A randomised repeated measures design will be used in which each subject receives all diets in a random order. The test foods will be as follows: 1. White bread: 105 g (Reference) plus 188 ml water (Treatment: Chew) 2. Soy-purple wheat kibbled bread: 163 g plus 150 ml water (Treatment: Chew) 3. Purple wheat kibbled bread: 125 g plus 171 ml water (Treatment: Chew) 4. White bread: 105 g (Reference) homogenized with 188 ml water (Treatment: Swallow) 5. Soy-purple wheat kibbled bread: 163 g homogenized with 150 ml water (Treatment: Swallow) 6. Purple wheat kibbled bread: 125 g homogenized with 171 ml water (Treatment: Swallow) 7. White bread: 105 g (Reference) plus 188 ml water (Treatment: Swallow without chewing) 8. Soy-purple wheat kibbled bread: 163 plus 150 ml water (Treatment: Swallow without chewing) 9. Purple wheat kibbled bread: 125 g plus 171 ml water (Treatment: Swallow without chewing). An additional 150 ml of water will be consumed with all diets. Foods given above contain approximately 40 g of available carbohydrate. The exact available carbohydrate content of all diets will be determined by in vitro digestive analysis prior to calculating the results. The breads will be prepared in the Plant & Food Research, food safe labs. Breads will be baked on every Friday and divided into required portions and frozen until testing so that all subjects are tested with kibbled grain and white breads that have had identical treatment. Respondents will be asked to come for the trial between Mondays to Fridays. The breads will be thawed to room temperature overnight before being served. Participants will be asked to ingest breads 1, 2, 3 and 7, 8, 9 with and without chewing respectively, which will take 6 sessions for the subject. Breads 4. 5, 6 will be thawed to room temperature (overnight), homogenized with 150 ml of water not more than 1 h before testing, and consumed in 3 sessions. The subjects will be given 300 ml of water to be consumed with all diets. On each test day the volunteers will be seated and asked to remain so for the duration of the test. Once each subject is relaxed and comfortable a baseline blood sugar measurement will be taken in duplicate for that day. Each subject will then be given a test food and instructed to consume the whole amount within a ten-minute period. Blood glucose testing will be by finger prick blood sampling. Samples will be thus be collected at 0 (baseline x 2), 15, 30, 45, 60, 90 and 120 minutes. Blood glucose will be measured immediately using a HemoCue® blood glucose meter. A visual analogue scale will be used to measure appetite over the two hours at 0, 30, 60, 90 and 120 mins. The washout period for this crossover study is 48 hours between each session.
Sponsors
The New Zealand Institute for Plant & Food Research Limited
Study design
Allocation
Randomised controlled trial
Intervention model
Crossover
Primary purpose
Prevention
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
18 Years to 65 Years
Healthy volunteers
Yes
Inclusion criteria
• Age: Aged between 18 and 65. • Sex: Male or female. • Glucose tolerance: No history of diabetes or evidence of glucose intolerance in a preliminary screening test (glycated haemoglobin below 40 mmol/mol ). • Gluten and soy tolerance: No history of intolerance towards gluten, soy and bread products. • BMI: Volunteers have a body mass index between 18 and 35 kg/m2 • Health: Healthy as gauged by self-assessment and result on the General Health Questionnaire. • Agreement: Subject having given written informed consent to comply with the conditions of the trial.
Exclusion criteria
• Glucose intolerance: Any history of diabetes or evidence of glucose intolerance in a preliminary test. • Gluten and soy intolerance: Any history of intolerance towards gluten, soy and bread products. • Non-fasting: Having consumed anything apart from water in the twelve hours prior to the test.
Outcome results
None listed