Effects of Polyphenols Found in Pomegranate Juice on Postprandial Blood Glucose in Vivo

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 commercially available food supplements together with white bread and then determining the glycaemic response. The blood glucose response of bread will be determined initially as a control reference. All 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.

Conditions

• Hyperglycaemia

Interventions

OTHER

Control without pomegranate juice

Control meal of 109 g white bread and 200 ml water (containing the same amount and type of sugars naturally present in pomegranate juice) to which the response of the test meal with pomegranate juice will be compared to.

OTHER

Test with pomegranate juice

The test meal will contain 109 g white bread and 200 ml of pomegranate juice whose response will be compared to that of the control meal.

Sponsors & Collaborators

• University of Leeds

  lead OTHER

Principal Investigators

• Gary Williamson · Professor and Chair of Functional foods

• Hilda Nyambe · Postgraduate research student

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

2015-11-30

Primary Completion

2016-03-31

Completion

2016-03-31

Countries

• United Kingdom

Study Locations