Effect of a Beverage Comprised of Compounds From Olives on Post-prandial Blood Glucose Responses in Healthy Volunteers

Summary

Consumption of carbohydrate containing foods or sugary drinks brings about changes to the blood glucose levels. After a meal or drink, blood glucose rises 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 in healthy people.

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.

Research has shown that diets that give rise to a high glucose response are associated with a number of abnormalities like increased risk of metabolic syndrome. Metabolic syndrome mostly comprises of insulin resistance and glucose intolerance which gives an increased risk of type 2 diabetes. 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. 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. Laboratory 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.

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 pomegranate polyphenols together with different carbohydrate sources which will define the 6 different interventions. The blood glucose response of bread will be determined initially as a control reference. All meals will be consumed in random order.

Analysis will be done by measuring blood glucose response after consumption of the control reference meal and the test meal containing polyphenols and then determining the incremental area under the glucose curve.

THE SIX DIFFERENT INTERVENTIONS MAY OR MAY NOT BE COMBINED FOR PURPOSES OF PUBLISHING RESULTS. EACH INTERVENTION WILL AIM TO HAVE AT LEAST 10 PARTICIPANTS.

Conditions

• Hyperglycemia

Interventions

OTHER

Control (study 1)

Control meal will comprise of 50 g glucose dissolved in 200 ml water, to which the response of the test meals will be compared to

OTHER

Test (study 1)

The test meal will comprise 50 g glucose in 200 ml water plus 50 mg oleuropein from olives

OTHER

Control (study 2)

Control meal will comprise 109 g white bread to give 50 g available carbohydrate and 200 ml water, to which the response of the test meals will be compared to

DIETARY_SUPPLEMENT

Test (study 2)

The test meal will comprise 109 g white bread plus 50 mg oleuropein from olives dissolved in 200 ml water

OTHER

Control (study 3)

Control meal will comprise whole-meal bread to give 50 g available carbohydrate and 200 ml water, to which the response of the test meals will be compared to

DIETARY_SUPPLEMENT

Test (study 3)

The test meal will comprise whole-meal bread plus 50 mg oleuropein from olives dissolved in 200 ml water

OTHER

Control (study 4)

Control meal will comprise 50 g sucrose in 200 ml water, to which the response of the test meals will be compared to

DIETARY_SUPPLEMENT

Test (study 4)

The test meal will comprise 50 g sucrose in 200 ml water plus 50 mg oleuropein from olives

OTHER

Control (study 5)

Control meal will comprise 25 g sucrose in 200 ml water, to which the response of the test meals will be compared to

OTHER

Test (study 5)

The test meal will comprise 25 g sucrose in 200 ml water plus 160 mg oleuropein from olives

OTHER

Control (study 6)

Normal diet 3 days prior to the visit day and 109 g bread with 200 ml water on the study day

OTHER

Test (study 6)

High carbohydrate diet (23% fat, 55% carbohydrates and 22% protein) 3 days prior to the visit day and 109 g bread with 200 ml water on the study day

OTHER

Control (study 7)

Normal diet 3 days prior to the visit day and 109 g bread with 200 ml water on the study day

OTHER

Test (study 7)

High fat diet (44% fat, 34% carbohydrates and 22% protein) 3 days prior to the visit day and 109 g bread with 200 ml water on the study day

Sponsors & Collaborators

• University of Leeds

  lead OTHER

Principal Investigators

• Gary Williamson · University of Leeds

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

NONE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Max Age

65 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2016-07-31

Primary Completion

2017-08-31

Completion

2017-09-30