Effects of Seaweed Extract on Postprandial Response to White Bread

Not Applicable

Active, not recruiting

• Conditions: Glucose Intolerance; Postprandial Hyperglycemia; Diabetes Mellitus Risk; Glycemic Control; Healthy Subjects
• Interventions: Dietary Supplement: White bread; Dietary Supplement: Seaweed extract HD and white bread; Dietary Supplement: Seaweed extract LD and white bread

• Registration Number: NCT05460884
• Lead Sponsor: University College Dublin

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.

Study Timeline

• Study Start: 2020-09-12
• Study First Submitted: 2022-07-13
• Study First Submitted QC: 2022-07-13
• Study First Posted: 2022-07-15
• Status Verified: 2023-02
• Last Update Submitted: 2023-02-17
• Last Update Posted: 2023-02-21
• Primary Completion: 2023-10-31
• Study Completion: 2023-10-31

Recruitment & Eligibility

• Status: ACTIVE_NOT_RECRUITING
• Sex: All
• Target Recruitment: 20

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

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Control	White bread	Participants will consume 109 g of white bread
Experimental 2: Seaweed extract at higher dose (HD) and white bread	Seaweed extract HD and white bread	Participants will consume 109 g of white bread with 1g of seaweed extract
Experimental 1: Seaweed extract at lower dose (LD) and white bread	Seaweed extract LD and white bread	Participants will consume 109 g of white bread with 0.5g of seaweed extract

Primary Outcome Measures

Name	Time	Method
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 Outcome Measures

Name	Time	Method
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.
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.

Trial Locations

Locations (1)

Institute of Food and Health Volunteer Suite; Science Center South, UCD; 🇮🇪 Dublin, Dublin 2, Ireland