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Efficacy of Polyphenols From Milk and Dark Chocolate

This study has been completed.
Information provided by (Responsible Party):
Nestlé Identifier:
First received: August 6, 2007
Last updated: July 12, 2013
Last verified: July 2013
Dark chocolate is one of the richest sources of polyphenols though it has been hypothesised that the bioavailability and therefore probably the bioefficacy of epicatechin from milk chocolate was reduced compared to dark. This study is designed to compare milk and dark chocolate as a source of polyphenols with a control "chocolate" for improving a risk biomarker for vascular disease.

Condition Intervention
No Disease Dietary Supplement: Dark Chocolate Dietary Supplement: Milk Chocolate Dietary Supplement: Control (polyphenol-free) "Chocolate"

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single Blind (Investigator)
Primary Purpose: Basic Science
Official Title: Efficacy of Polyphenols From Milk and Dark Chocolate

Further study details as provided by Nestlé:

Primary Outcome Measures:
  • Change in Reactive Hyperemia Index (RHI) From Baseline (20 Min Before Product Intake) to 2 Hours Following Product Intake [ Time Frame: Baseline and 2 hours ]
    Value of RHI at 2 hours minus value at baseline. RHI reflects the endothelial function of a vessel at the distal phalanx of a finger, i.e. the capacity of the vessel to dilate after an ischemia. RHI is the increase of blood flow following the occlusion of the brachial artery during 5 minutes by the inflation of an armcuff. RHI was measured by peripheral arterial tonometry using a fingerprobe connected to an EndoPat analyser.

Secondary Outcome Measures:
  • Change in Arterial Stiffness From Baseline (20 Min Before Product Intake) to Two Hours Following Product Intake [ Time Frame: baseline and 2 hours ]

    Value of arterial stiffness at 2 hours minus value at baseline. Arterial stiffness is also automatically calculated by peripheral arterial tonometry which consists in measuring the peripheral vessel endothelial response to an ischemia provoked by a 5-min occlusion of the humeral artery using an armcuff.

    An increase in arterial stiffness means an increase in the resistance of the vessel wall which reflects an impaired endothelial response to ischemia.

Enrollment: 6
Study Start Date: June 2008
Study Completion Date: April 2012
Primary Completion Date: June 2009 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: dark chocolate containing polyphenols
dark chocolate
Dietary Supplement: Dark Chocolate
1 portion
Experimental: Milk chocolate containing polyphenols
Bespoke milk chocolate
Dietary Supplement: Milk Chocolate
1 portion
Active Comparator: Control chocolate with no polyphenols
cocoa-free chocolate
Dietary Supplement: Control (polyphenol-free) "Chocolate"
one portion

Detailed Description:

Dark chocolate is one of the richest sources of polyphenols, for example, a standard 40g portion of dark chocolate contains 400-800 mg of polyphenols, compared to red wine (170 mg /100ml) or an apple (200 mg/piece). Cocoa polyphenols, most notably the catechins, can exist in both lipid and water-based environments (amphipathic), meaning they can spare both lipophilic and hydrophilic vitamins. There have been a number of human trials conducted using chocolate or cocoa and measuring various endpoints. Most have been conducted with dark chocolate. An article in Nature found that the bioavailability of epicatechin from milk chocolate was substantially reduced compared to dark, and even dark taken with a glass of milk (Serafini et al 2003). The hypothesis was that the milk proteins bind to polyphenols, making them unavailable. Subsequent studies have not been able to reproduce this, but none have been conducted using solid chocolate as the first study, all have been done using a drink matrix, which may completely alter the binding interactions of the polyphenols and protein. To this end, this study is designed to compare solid chocolates as a source of polyphenols for improving a risk biomarker for vascular disease.

This study is designed as a blinded, three arm crossover trial. The primary outcome measure is to compare endothelial function after consumption of 3 chocolates (1 milk, 1 dark, 1 polyphenol-free control) with a secondary outcome of arterial stiffness. All volunteers will take all chocolate types in a crossover design. Subjects will undergo medical screening, anthropometry, physical activity and dietary assessments before randomization for the order of consumption.


Ages Eligible for Study:   25 Years to 45 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • 25- 45 years, male and female
  • Healthy as determined by the medical questionnaire
  • Normal weight: BMI 19 - 25
  • Having given informed consent

Exclusion Criteria:

  • Intestinal or metabolic diseases/disorders such as diabetic, renal, hepatic, hypertension, pancreatic or ulcer, including lacto-intolerance.
  • Have had a major gastrointestinal surgery.
  • Have a regular consumption of medication.
  • Have an exceptionally high intake of chocolate or similarly high polyphenol foods.
  • Have a high and regular intake of vitamin supplements
  • Have an alcohol intake: > 2 units a day
  • Patient who cannot be expected to comply with treatment.
  • Smoker
  • Having a nut allergy
  • Unwilling to consume chocolate
  • Currently participating or having participated in another clinical trial during the last 3 weeks.
  • Having given blood in the past three weeks
  • More than 3 x 45 min of exercise per week
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT00513344

Nestle Research Center
Lausanne, Vaud, Switzerland, 1000
Sponsors and Collaborators
Principal Investigator: Karen A Cooper, PhD Nestlé
Study Director: Gary Williamson, PhD Nestlé
  More Information

Responsible Party: Nestlé Identifier: NCT00513344     History of Changes
Other Study ID Numbers: 06.38.MET
Study First Received: August 6, 2007
Results First Received: March 28, 2013
Last Updated: July 12, 2013

Keywords provided by Nestlé:
Endothelial function
Arterial stiffness
Dark chocolate
Milk chocolate
Polyphenols processed this record on July 21, 2017