for males ages 30-50 (full criteria)
Healthy Volunteers
healthy people welcome
at UC Davis
study started
completion around
Principal Investigator
by Carl L. Keen, PhD (ucdavis)



This study aims to obtain data on the potential influence of Vine to Bar product(s) containing Chardonnay marc on cardiometabolic health. These initial studies will inform the design and timing of data collection for future dietary intervention trials that will examine the influence of Chardonnay marc intake on outcomes/biomarkers of both cardiometabolic health and the gut microbiome. This includes collecting data on the potential differences in response to the products based on the unique food matrix for each of the products that will be tested. Moreover, as there is a paucity of data on the influence of cocoa flavanol intake on vascular function beyond 4 hours post intake, the response of the selected outcomes will be assessed after 6 hours of flavanol intake. This is a time point that captures the increased circulating presence of microbial derived flavanol metabolites.

Official Title

Preclinical Trials to Determine the Range of Chardonnay Mark Intake for Improved Metabolic and Vascular Response.


The current set of trials will be of an acute (single intake, followed over 6 hours) that examines the postprandial response of individuals to the products. These preclinical trials will be conducted in the same individuals in an crossover design in order to limit individual variability, and keep the numbers small (5 individuals maximum), but still be able to assess the response to the different products.


Cardiovascular Diseases, Vascular Dilation, Oxidative Stress, Low Flavanol Cocoa Powder, High Flavanol Cocoa Powder, Vine to Bar Chocolate - 2 servings, Vine to Bar Chocolate - 1 serving, Vine to Bar Chocolate covered almonds, Two Servings of Vine to Bar Chocolate, One Serving of Vine to Bar Chocolate


You can join if…

Open to males ages 30-50

  • Screening or Visit 1 Reactive Hyperemia Index (RHI; EndoPAT 2000) < 2.0
  • Subject is willing and able to comply with the study protocols.
  • Subject is willing to participate in all study procedures
  • BMI 25.0 - 35 kg/m2

You CAN'T join if...

  • BMI ≥ 35 kg/m2
  • Indivduals that weight less than a 110 lbs
  • Donation of blood within the previous 30 days
  • Visit 1 Reactive Hyperemia Index (RHI; EndoPAT 2000) ≥ 2.0
  • 1 ug/ml and 3 ug/ml collagen screening maximal platelet aggregatory response of < 65%.
  • Platelet counts < 150,000 / ul
  • Anemia, which includes self report, or a screening hemoglobin and hematocrit that is less than the normal reference range or as diagnosed by study physician upon review of complete blood cell count reports.
  • Dislike or allergy for nuts, cocoa or grape products
  • Self-reported use of daily anticoagulation agents including aspirin, NSAIDs
  • Vegan, Vegetarians, food faddists or those consuming a non-traditional diet
  • Fruit consumption ≥ 3 cups/day
  • Vegetable consumption ≥ 4 cups/day
  • Nut intake ≥ 2 servings/ week
  • Coffee/tea ≥ 3 cups/day
  • Dark chocolate ≥ 3 oz/day
  • Self-reported restriction of physical activity due to a chronic health condition
  • Self-reported chronic/routine high intensity exercise
  • Self-reported diabetes
  • Blood pressure ≥ 140/90 mm Hg
  • Self-reported renal or liver disease
  • Self-reported heart disease, which includes cardiovascular events and stroke
  • Peripheral artery disease, Raynaud's syndrome
  • Inability to properly place or wear the PAT probes or abnormal measurements on pre- screening PAT
  • Self-reported cancer within past 5 years
  • Self-reported malabsorption
  • Currently taking prescription drugs or supplements.
  • Supplement use or unwillingness to stop any supplement use, including herbal, plant or botanical, fish oil, oil supplements a month prior to study enrollment.
  • Indications of substance or alcohol abuse within the last 3 years
  • smoking, vaping, cannabis use
  • Current enrollee in a clinical research study.


  • Academic Surge, University of California, Davis accepting new patients
    Davis California 95616 United States

Lead Scientist at University of California Health

  • Carl L. Keen, PhD (ucdavis)
    Professor, Nutrition, College of Agricultural and Environmental Sciences. Authored (or co-authored) 553 research publications


accepting new patients
Start Date
Completion Date
University of California, Davis
Study Type
Expecting 5 study participants
Last Updated