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.
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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
300 mg capsule of Grape Seed Extract; 1 capsule will be consumed for an acute post-prandial study day and 1 capsule will be consumed daily for 30 days.
300 mg capsule of maltodextrin; 1 capsule will be consumed for an acute post-prandial study day and 1 capsule will be consumed daily for 30 days.
VA Hospital, Mather
Mather, California, United States
Changes in insulin resistance
Insulin resistance will be assessed by comparing the baseline fasting insulin concentration to the fasting insulin concentration after intervention period of 30 days; the Homeostatic Model Assessment (HOMA) value will be utilized for comparisons.
Time frame: Baseline and 30 days
Changes in oxidized LDL (oxLDL) concentrations
Changes in oxLDL concentrations will be assessed by ELISA methodology. Changes in the 24 hour post-prandial response will be assessed at one hour intervals during the post-prandial study days, after capsule consumption and eating 3 high fat meals.
Time frame: Baseline and 24 hour post-prandial response
Changes in oxidative stress
Changes in the 24 hour post-prandial oxidative stress response will be assessed at one hour intervals during the post-prandial study days, after capsule consumption and eating 3 high fat meals. Changes in oxidative stress will be assessed by measuring cytokine production using ELISA methodology.
Time frame: Baseline and 24 hour post-prandial response
Changes in vascular stress
Changes in oxidative stress will be assessed by flow mediated dialysis (FMD). Changes will be assessed at baseline and one hour after capsule consumption and eating a high fat breakfast meal.
Time frame: Baseline and 1 hour post-prandial
Changes in insulin response
Changes in the 24 hour post-prandial insulin response will be assessed at one hour intervals during the post-prandial study days, after capsule consumption and eating 3 high fat meals.
Time frame: Baseline and 24 hour post-prandial response
Changes in oxidized LDL (oxLDL) concentrations
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.
QUADRUPLE
Enrollment
19
Changes in oxLDL concentrations will be assessed by ELISA methodology. Changes in the 24 hour post-prandial response will be assessed at one hour intervals during the post-prandial study days, after capsule consumption and eating 3 high fat meals. The response from the baseline visit will be compared to the response obtained during the day 30 visit.
Time frame: Baseline and 30 days
Changes in insulin response
Changes in the 24 hour post-prandial insulin response will be assessed at one hour intervals during the post-prandial study days, after capsule consumption and eating 3 high fat meals. The response from the baseline visit will be compared to the response obtained during the day 30 visit.
Time frame: Baseline and 30 days
Changes in oxidative stress
Changes in the 24 hour post-prandial oxidative stress response will be assessed at one hour intervals during the post-prandial study days, after capsule consumption and eating 3 high fat meals. Changes in oxidative stress will be assessed by measuring cytokine production using ELISA methodology. The response from the baseline visit will be compared to the response obtained during the 30 day visit.
Time frame: Baseline and 30 days
Changes in vascular stress
Changes in oxidative stress will be assessed by flow mediated dialysis (FMD). Changes will be assessed at baseline and one hour after capsule consumption and eating a high fat breakfast meal. Results obtained during the first post-prandial study visit will be compared to those obtained 30 days later.
Time frame: Baseline and 30 days