Clinical trial NCT01889368: Effect of a Grape Seed Extract (GSE) on Insulin Resistance
Official title: Effect of a Grape Seed Extract (GSE) on Insulin Resistance
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Metabolic Syndrome
Keywords: Insulin resistance
Central adiposity
Elevated blood pressure
Vascular reactivity
Elevated triglycerides
Low high-density lipoprotein (HDL)
Lead sponsor: University of California, Davis
Sponsor class: OTHER
Collaborators: name: Illinois Institute of Technology
First posted: 2013-06-28
Enrollment: 19
Sex: ALL
Minimum age (years): 20
Maximum age (years): 70
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: BASIC_SCIENCE

Brief summary: In people with the metabolic syndrome, the investigators hypothesize that administration of a single 300 mg dose of a grape seed extract (GSE) will reduce insulin resistance (how well cells in the body can take up and use glucose), oxidative stress, and the amount of oxidized LDL in the blood during a 24 hour period. These measurements will be assessed at hourly intervals during the 24 hour study day protocol. Additionally, the investigators hypothesize that daily administration of 300 mg of GSE for 30 days will decrease baseline insulin resistance, oxidative stress, and the level of oxidized LDL in the blood.

Detailed description: In people with the metabolic syndrome, the investigators hypothesize that administration of a single 300 mg dose of a grape seed extract (GSE) will reduce insulin resistance (how well cells in the body can take up and use glucose), oxidative stress, and the amount of oxidized LDL in the blood during a 24 hour period. Each of these can be elevated after eating high fat meals, which are commonly found in the average Western diet. To better assess the impact of these high fat eating patterns, three standardized high fat meals will be served during the study day: breakfast, lunch, and dinner. Measurements in the blood will be assessed at hourly intervals during the 24 hour study day protocol. Additionally, the investigators hypothesize that daily administration of 300 mg of GSE for 30 days will decrease baseline insulin resistance, oxidative stress, and the level of oxidized LDL in the blood when this 24 hour study day protocol is repeated and breakfast, lunch, and dinner are again served.

Insulin resistance will be measured using a comparison of insulin and glucose levels in the blood. Oxidative stress, a measure of inflammation, will be measured by cytokines levels in the blood. The level of oxidized LDL will be measured in the blood. The investigators also plan to undertake a subsidiary pharmacokinetic study on the various polymers which are known to be present in grape seed extracts to determine their bio-availability and their relationship to the biological effects observed.

Eligibility criteria: Inclusion Criteria

* Metabolic Syndrome, based on subject meeting at least 3 of the following criteria:
* Abdominal obesity with waist circumference \> 40 inches in men or \> 35 inches in women,
* Pre-hypertension with blood pressure \> 135/85,
* Fasting blood glucose levels above 110 mg/dl,
* Plasma triglyceride levels in excess of 150 mg/dl,
* HDL levels below 40 mg/dl in men or 50 mg/dl in women.

Exclusion Criteria:

* Any known systemic disease,
* Diabetes,
* Alcohol consumption \> 1-2 drinks/week,
* Taking any medications or supplements that will affect metabolism, their ability to exercise or oxidative status,
* Smokers,
* Female subjects having abnormal menstrual cycles, taking oral contraceptives, pregnant or lactating.

Primary outcomes:
measure: Changes in insulin resistance
timeFrame: Baseline and 30 days
Secondary outcomes:
measure: Changes in oxidized LDL (oxLDL) concentrations
timeFrame: Baseline and 24 hour post-prandial response
measure: Changes in oxidative stress
timeFrame: Baseline and 24 hour post-prandial response
measure: Changes in vascular stress
timeFrame: Baseline and 1 hour post-prandial
measure: Changes in insulin response
timeFrame: Baseline and 24 hour post-prandial response
measure: Changes in oxidized LDL (oxLDL) concentrations
timeFrame: Baseline and 30 days
measure: Changes in insulin response
timeFrame: Baseline and 30 days
measure: Changes in oxidative stress
timeFrame: Baseline and 30 days
measure: Changes in vascular stress
timeFrame: Baseline and 30 days
Other outcomes:
Locations:
city: Mather
country: United States
facility: VA Hospital, Mather
state: California
Study officials:
affiliation: University of California, Davis
name: Chulani T Kappagoda, MD, PhD
role: PRINCIPAL_INVESTIGATOR
References: