Effect of a Grape Seed Extract (GSE) on Insulin Resistance
Condition: Metabolic Syndrome
MeSH terms: Metabolic Syndrome; Insulin Resistance
Study type: Interventional

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.
    

Intervention name(s): Grape Seed Extract; Placebo
Intervention type(s): Dietary Supplement; Dietary Supplement
Intervention description(s): 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.
Other intervention name(s): MegaNatural Gold; Maltodextrin
Intervention MeSH terms: Grape Seed Extract
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Basic Science
Keywords: Insulin resistance; Central adiposity; Elevated blood pressure; Vascular reactivity; Elevated triglycerides; Low high-density lipoprotein (HDL)