Postprandial Responses to Hydroxytyrosol-enriched Bread

Study Overview
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Brief Summary
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The amelioration of postprandial glucose and insulin responses to bread is of great importance since it may have significant beneficial effects on health. A number of studies have shown that hydroxytyrosol may have positive metabolic effects. However, this compound presents high hydrophilicity which constitutes the major barrier to its potential application in foods. Microencapsulation arises as a technological strategy to protect it and increase its stability. Alpha-cyclodextrin besides being a great carrier molecule, seems to also be beneficial to postprandial glucose levels. Enrichment of bread with encapsulated hydroxytyrosol could examine potential postprandial benefits. Ten healthy normoglycemic subjects will participate in the study and will be provided with either a solution of glucose (reference food) or white wheat bread or wheat bread enriched with a-cyclodextrin or wheat bread enriched with hydroxytyrosol encapsulated in a-cyclodextrin, with 1-week intervals in amounts that yielded 50 g of available carbohydrates. Venous blood samples will be collected before consumption and at 30, 45, 60, 90, 120 and 180 min postprandially. Postprandial glucose, insulin and appetite-related hormone responses as well as glycemic index (GI) and subjective appetite ratings will be evaluated.

Official Title
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Postprandial Responses of Healthy Subjects to Wheat Bread Enriched With Encapsulated Hydroxytyrosol

Conditions
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Postprandial Responses

Intervention / Treatment
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* Other: Enriched wheat bread


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Normal body mass index Stable body weight for at least 3 months before enrollment Normal exercise, eating and drinking habits Exclusion Criteria: Pregnancy and lactation Chronic medical illness (diabetes mellitus, cardiovascular disease, chronic liver, kidney, polycystic ovary syndrome or untreated thyroid disease) Use of nutritional supplements History of drug and/or alcohol abuse Psychiatric disease

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 40 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Glucose Solution<br> | Other: Enriched wheat bread<br>* Either 50g of glucose dissolved in 250mL water or white wheat bread or wheat bread enriched with 5mg a-cyclodextrin or wheat bread enriched with a 5mg mixture of a-cyclodextrin and encapsulated hydroxytyrosol (per 50g of available carbohydrates).<br>|
| Active Comparator: Wheat bread enriched with a-cyclodextrin<br> | Other: Enriched wheat bread<br>* Either 50g of glucose dissolved in 250mL water or white wheat bread or wheat bread enriched with 5mg a-cyclodextrin or wheat bread enriched with a 5mg mixture of a-cyclodextrin and encapsulated hydroxytyrosol (per 50g of available carbohydrates).<br>|
| Experimental: Wheat bread enriched with hydroxytyrosol encapsulated in a-cyclodextrin<br> | Other: Enriched wheat bread<br>* Either 50g of glucose dissolved in 250mL water or white wheat bread or wheat bread enriched with 5mg a-cyclodextrin or wheat bread enriched with a 5mg mixture of a-cyclodextrin and encapsulated hydroxytyrosol (per 50g of available carbohydrates).<br>|
| Placebo Comparator: White wheat bread<br> | Other: Enriched wheat bread<br>* Either 50g of glucose dissolved in 250mL water or white wheat bread or wheat bread enriched with 5mg a-cyclodextrin or wheat bread enriched with a 5mg mixture of a-cyclodextrin and encapsulated hydroxytyrosol (per 50g of available carbohydrates).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Glycaemic Index | Glycaemic Index of the enriched breads | Change between preprandial glucose measurements until 120 minutes postprandially | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Insulin Response | Insulin Responses of the volunteers to the enriched breads (by a sandwich ELISA method, using a commercially available human insulin kit) | Change between preprandial insulin measurements until 180 minutes postprandially | 
| Appetite ratings | Appetite ratings after the consumption of the enriched breads (evaluation of subjective appetite ratings, use of visual analogue scales) | Change between preprandial subjective appetite measurements until 180 minutes postprandially | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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hydroxytyrosol, a-cyclodextrin, bread, glycaemic index, appetite