None listed
Conditions
Brief summary
The key research question is whether the reduction in hypoglycaemic response following a kiwifruit pre-load prior to a Weet-bix™ meal improves exercise performance. Our previous research has shown that ingestion of kiwifruit 30 minutes prior to Weet-Bix™ substantially reduces glycaemic response peak height when compared to Weet-Bix™ fed alone or WeetBix consumed at the same time as kiwifruit and reduces the hypoglycaemic state that commonly occurs after eating available carbohydrates. We hypothesise that the increase in available glucose in the circulation will fuel muscles and therefore improve the exercise performance. Standard glycaemic response testing protocols will be used, with an exercise intervention of 30 minutes cycling at 135 minutes after the last test meal. The available carbohydrate of all foods will be determined in-house before the trial to ensure all test diets contain 40 g of available carbohydrate. The test foods will be as follows: 1. Weet-Bix™: containing moistened with 180 ml water 2. Kiwifruit 30 minutes prior to Weet-Bix™ 3. Weet-Bix™ 30 minutes prior to another portion of Weet-Bix™: Weet-Bix™ A randomised cross-over design will be used in which all participants receive each diet once, with a minimum of a week separating each trial day. Blood glucose response will be measured at nine time points over a 195 minute period via finger prick. Additional capillary blood samples will be taken at eight time points over this period for measurement of insulins, glucagon and interleukin 6 and three venous blood samples will be taken at baseline, 120 mins (pre-exercise) and 165 mins (post-exercise) after the second test meal for measurements of oxidative stress. Exercise performance will be measured by cardiopulmonary parameters, power output, exercise duration and ratings of perceived exertion. We will also collect measures of hunger via a visual analogue questionnaire and mood with a perceived mood state questionnaire at baseline, 120 mins and 165 mins.
Interventions
Each participant will receive each intervention listed below on a trial day, to consume within 10 minutes, in a randomised order separated by at least one week. Participants will
1. Weet-Bix™: containing 40 g available carbohydrate moistened with 180 ml water
2. Kiwifruit 30 minutes prior to Weet-Bix™: Weet-Bix™ (20 g available carbohydrate) and kiwifruit (20 g available carbohydrate)
3. Weet-Bix™ 30 minutes prior to another portion of Weet-Bix™: Weet-Bix™ (20 g x 2 available carbohydrate) moist
Each participant will receive each intervention listed below on a trial day, to consume within 10 minutes, in a randomised order separated by at least one week. Participants will 1. Weet-Bix™: containing 40 g available carbohydrate moistened with 180 ml water 2. Kiwifruit 30 minutes prior to Weet-Bix™: Weet-Bix™ (20 g available carbohydrate) and kiwifruit (20 g available carbohydrate) 3. Weet-Bix™ 30 minutes prior to another portion of Weet-Bix™: Weet-Bix™ (20 g x 2 available carbohydrate) moistened with 180 ml water. 135 minutes after the dietary intervention, exercise performance (power output, time and distance) will be assessed with a 30 minute cycle.
Sponsors
The New Zealand Institute for Plant & Food Research
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 55 Years
Healthy volunteers
Yes
Inclusion criteria
• Age: Aged between 18 and 55. • Sex: Male or female. • Glucose tolerance: No history of diabetes or evidence of glucose intolerance in a preliminary screening test. • HBA1c <40 mmol/mol • BMI: Volunteers have a body mass index between 18.5 and 30 kg/m2 • Health: Healthy as gauged by self-assessment and result on the General Health Questionnaire. • Agreement: Participant 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 (Greater than or equal to 6.0mmol/l fasting glucose, International Diabetes Federation recommendation) and HbA1c greater than 40 mmol/mol. Non-fasting: Having consumed anything apart from water in the twelve hours prior to the test. Allergic or intolerant kiwifruit or wheat Pregnant or breastfeeding or planning to get pregnant in the near future. Long term chronic illnesses requiring treatment, such as cancer and cardiovascular disease. Gut conditions or drugs effecting gut transit time, such as irritable bowel syndrome, peptic ulcers and laxatives. Habitual Physical Activity questionnaire sports index greater than 4, assessed by a Baecke questionnaire. Participants will be excluded if they are unwilling or unable to provide informed consent or comply with the study procedures. Participants that have health conditions that impair their ability to perform the exercises or may be aggravated by the exercises in this study (e.g. injury, hernia, back or joint pain, cardiovascular and breathing problems). Participants that have Type I or II diabetes or are pre-diabetic (ii) blood borne diseases (e.g. hepatitis), (iii) clinically diagnosed high/low blood pressure, (iv) recent bacterial or viral illness or (v) are taking medication that affects the properties of blood (e.g. blood clotting).
Outcome results
None listed