Diabetes Mellitus Risk, Glucose Intolerance, Glycemic Control, Healthy Subjects, Postprandial Hyperglycemia
Conditions
Keywords
seaweed, Ascophyllum, blood glucose, insulin, postprandial, hyperglycemia
Brief summary
The study is designed to determine whether seaweed extract added to a carbohydrate-rich meal, can lower blood glucose levels after its consumption, and hence lower its glycaemic index, and if this effect is mediated through effects on insulin. It is designed as an acute, randomised, cross-over, controlled, three-arm dietary intervention trial in healthy subjects. Participants will be asked to consume either white bread, white bread with lower dose of seaweed extract or white bread with higher dose of seaweed extract.The effects on plasma glucose levels and levels of insulin will be determined over 3 hours after the consumption.
Detailed description
It has been shown in a large number of in vitro studies that seaweed extracts act as potent inhibitors of enzymes of carbohydrate digestion suggesting their potential to modulate postprandial glycaemic response and prevent the damaging effects of hyperglycaemic state. However, the results from human trials are limited and inconsistent. The investigators confirmed that the in vitro inhibitory effects of seaweed extracts depend on the type, level and ratio of bioactive compounds, and optimised the composition of the extract to obtain the most potent one, to be tested in the proposed study. The present study will determine whether the seaweed extract added to a carbohydrate-rich meal, can lower blood glucose levels after its consumption, and hence lower its glycaemic index, and if this effect is mediated through effects on insulin or determined by the individual levels of digestive enzymes. Healthy volunteers will be asked to consume three different meals: (1) white bread; (2) white bread with the lower dose (LD) of the extract; (3) white bread with the higher dose (HD) of the extract The levels of glucose and insulin will be measured in plasma isolated from blood samples obtained before and up to 3 hours after the consumption of each meal. Additional measurements taken at the screening will include blood pressure values and blood lipids levels. All participants will be characterized for the activity of salivary a-amylase.
Interventions
DIETARY_SUPPLEMENTSeaweed extract LD and white bread
109g of white bread with 0.5g of seaweed extract
DIETARY_SUPPLEMENTSeaweed extract HD and white bread
109g of white bread with 1g of seaweed extract
DIETARY_SUPPLEMENTWhite bread
109g of white bread
Sponsors
University College Dublin
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
PREVENTION
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)
Masking description
physically incorporated in the intervention
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
Yes
Inclusion criteria
* 18-65 years old * Healthy
Exclusion criteria
* Smoking * Diagnosis of any chronic illness (including diabetes, hypertension, gastrointestinal diseases etc.) * On long term prescribed medication (except contraceptives) * Pregnant or lactating * On a special diet or dietary regimen (for weight management or if regularly consuming fruit extract supplements) * Allergy to fruits vegetables or pollen * Unwillingness to follow dietary recommendations or record the diet during recommended period * Donated blood 4 weeks before or intend to donate blood during the study or 4 weeks after the last study samples * Participation in another research project in parallel which also involves dietary intervention (e.g. taking vitamin supplements) or requires sampling of blood
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Changes in maximal incremental plasma glucose level (iCmax) between baseline and endpoint within intervention groups vs. control. | Baseline, 15 min, 30 min, 45 min, 60 min, 90 min, 120 min, 150 min, 180 min | The incremental glucose levels will be determined for each time point (at 15, 30, 45, 60, 90, 120, 150 and 180 min) as the change in plasma glucose levels after the consumption of both levels of seaweed extracts concomitantly with white bread, or white bread only, compared to the glucose levels before the consumption of test meals (baseline value, t=0min). |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Changes in area under the curve of incremental plasma glucose levels (iAUC) in the intervention group vs. control | Baseline, 15 min, 30 min, 45 min, 60 min, 90 min, 120 min, 150 min, 180 min | The glucose iAUC will be determined from all incremental plasma glucose levels at the defined time points (0, 15, 30, 45, 60, 90, 120, 150 and 180 min) after the consumption of test and control meals based on trapezoid rule. |
| Changes in plasma insulin levels between baseline and endpoint within the intervention group vs. control | Baseline, 15 min, 30 min, 45 min, 60 min, 90 min, 120 min, 150 min, 180 min | nsulin levels measured at the baseline and at each time point (at 15, 30, 45, 60, 90,120, 150 and 180 min) after the consumption of test and control meals. |
Countries
Ireland
Outcome results
None listed