Effects of Carbohydrase-inhibiting Polyphenols on Glycaemic Response in Vivo

This study is currently recruiting participants. (see Contacts and Locations)
Verified March 2014 by University of Leeds
Sponsor:
Information provided by (Responsible Party):
Hilda Nyambe, University of Leeds
ClinicalTrials.gov Identifier:
NCT01994135
First received: November 19, 2013
Last updated: March 27, 2014
Last verified: March 2014
  Purpose

Consumption of carbohydrate containing foods or sugary drinks brings about changes to the blood glucose levels. After a meal or drink, blood glucose levels rise until it reaches a peak concentration usually after 30 minutes. When the body senses the increase in blood glucose, a hormonal process involving insulin takes place to ensure that the glucose is taken up from the blood for storage and where it is needed for energy in the body. This process then brings about a decrease in the concentration of glucose until it reaches approximately the starting concentration. The original concentration of glucose is attained approximately 2 hours after eating or drinking a carbohydrate food or sugary drink respectively.

Different carbohydrates and sugary drinks have different effects on blood glucose response depending on the amount as well as the type of carbohydrate. Those that give rise to a high glucose response compared to a reference carbohydrate (usually glucose) are said to be high glycaemic index (GI) foods and those with a lower glucose response compared to a reference carbohydrate (usually glucose) are said to be low glycaemic index (GI) foods.(1)

Research has shown that diets that give rise to a high glucose response are associated with a number of abnormalities like increased metabolic syndrome (2). Metabolic syndrome mostly comprises of insulin resistance and glucose intolerance which gives an increased risk of type 2 diabetes. (3) It also gives rise to other conditions like high blood pressure (arterial hypertension), elevated blood insulin levels (hyper-insulinemia), elevated amounts of fat in the liver (fatty hepatosis) and elevated amounts of lipids in the blood (dyslipidemia). After type 2 diabetes become clinically apparent, the risk of cardiovascular disease also rises. (4) Research has also shown that foods/drinks which raise blood glucose levels gradually (low GI) rather than rapidly (high GI) have health benefits which include reducing the risk of metabolic syndrome (5). In vitro studies have shown that polyphenols found in fruits, vegetables and plant based foods have a positive effect on carbohydrate metabolism and can lower the blood glucose levels. (6)

This research will determine whether the presence of polyphenols in the diet has any lowering effect on the blood glucose levels and hence the glycaemic index of foods. This will be determined by asking volunteers to consume polyphenol rich drink/food together with white bread and determine the glycaemic response. The GI of bread will be determined initially as a reference.

Analysis will be done by measuring blood glucose response to white bread alone as reference and then to white bread with test sample containing polyphenols and then determine GI and see how the GI of bread will be affected. Other analyses to be done are plasma insulin, glucagon, gastric inhibitory polypeptide (GIP) and glucagon like peptides-1 (GLP-1) as they all relate to glycaemic response.

Study hypothesis is that glucose metabolism will be affected.


Condition Intervention
Hyperglycaemia
Other: Reference food
Other: Test food dose 1
Other: Test food dose 2

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double Blind (Subject, Outcomes Assessor)
Primary Purpose: Basic Science

Resource links provided by NLM:


Further study details as provided by University of Leeds:

Primary Outcome Measures:
  • Changes in Incremental Area Under the Curve for glucose, insulin, GIP and GLP-1 will be determined [ Time Frame: Blood will be collected at different time points within 3 hours, twice a week, for two weeks per volunteer ] [ Designated as safety issue: No ]

Estimated Enrollment: 24
Study Start Date: March 2014
Estimated Primary Completion Date: December 2016 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: Reference food
The reference food is white bread
Other: Reference food
Reference food will be used to which test food samples will be compared to.
Experimental: Test food dose 1
Test food dose 1 response will be compared to reference test food
Other: Test food dose 1
Experimental: Test food dose 2
Test food dose 2 response will be compared to reference test food as well as to test food dose 1
Other: Test food dose 2

  Eligibility

Ages Eligible for Study:   18 Years to 75 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Group 1 - Healthy subjects

Not diabetic Fasting glucose (blood glucose level before breakfast) 3.9 -5.9mmol/L Not on long term prescribed medication (except contraceptives) Not pregnant or lactating Not on special diet (for losing weight or fruit extracts supplements) Aged 18-75

Group 2 - Metabolic syndrome risk group

Not diabetic With fasting glucose (blood glucose level before breakfast) in the range of 6.0 - 8.0mmol/l Not on long term prescribed medication (except contraceptives) Not pregnant or lactating Not on special diet (for losing weight or fruit extracts) Aged 18-75

Exclusion Criteria:

  • Group 1 - Healthy subjects

Not healthy Diabetic Fasting glucose (blood glucose level before breakfast) 3.9 -5.9mmol/L On long term prescribed medication (except contraceptives) Pregnant or lactating On special diet (for losing weight or fruit extracts supplements) Aged below 18years or above 75years

Group 2 - Metabolic syndrome risk group

Not diabetic With fasting glucose (blood glucose level before breakfast) above 8.0mmol/l On long term prescribed medication (except contraceptives) Pregnant or lactating On special diet (for losing weight or fruit extracts) Aged below 18years or above 75 years

  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01994135

Contacts
Contact: Hilda Nyambe +44 1133432957 fs07hs@leeds.ac.uk

Locations
United Kingdom
School of Food Science and Nutrition Recruiting
Leeds, West Yorkshire, United Kingdom, LS2 9JT
Contact: Hilda Nyambe    +44 1133432957    fs07hs@leeds.ac.uk   
Principal Investigator: Hilda Nyambe         
Sponsors and Collaborators
University of Leeds
Investigators
Study Chair: Gary Williamson University of Leeds
Principal Investigator: Hilda Nyambe University of Leeds
  More Information

No publications provided

Responsible Party: Hilda Nyambe, PhD candidate, University of Leeds
ClinicalTrials.gov Identifier: NCT01994135     History of Changes
Other Study ID Numbers: MEEC 12-037
Study First Received: November 19, 2013
Last Updated: March 27, 2014
Health Authority: United Kingdom: University of Leeds

Additional relevant MeSH terms:
Hyperglycemia
Glucose Metabolism Disorders
Metabolic Diseases

ClinicalTrials.gov processed this record on September 15, 2014