Dark Chocolate and Platelet Function in Humans

NCT ID: NCT01099150

Last Updated: 2012-04-17

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Clinical Phase

NA

Total Enrollment

42 participants

Study Classification

INTERVENTIONAL

Study Start Date

2009-03-31

Study Completion Date

2011-05-31

Brief Summary

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Cardiovascular disease is a major cause of mortality worldwide and responsible for one out of three global deaths. A main characteristic of cardiovascular disease is impaired blood flow and formation of blood clots. Platelets are clot-forming cells responsible for the prevention of bleeding. However, in disease conditions they may be overly activated, promoting blood clots and blockage of blood vessels.

Consumption of diets rich in fruits and vegetables decreases mortality from cardiovascular disease through a number of mechanisms, including the prevention of platelet clotting and aggregation. There is some evidence suggesting that platelet aggregation may be modulated through a group of compounds known as flavan-3-ols, which are found in various foods, and especially in cocoa. However, the mechanisms by which those compounds affect platelet function are not yet fully understood. We designed a human study assessing the mechanisms by which flavan-3-ols from cocoa beneficially affect platelet function and the platelet proteome.

Detailed Description

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Cardiovascular disease (CVD) is a primary cause of premature deaths worldwide, with incidence rates in the United Kingdom, particularly in Scotland, being amongst the highest worldwide. Thus identification of dietary components that most effectively prevent CVD is potentially of wide public health benefit.

Consumption of diets rich in plant-based products protects against the development of CVD. Such effects have been ascribed in part to polyphenols, which are non-nutritive but, potentially bioactive secondary metabolites ubiquitous found in fruits, vegetables, herbs, spices, teas and wines. The beneficial effects of polyphenols on CVD is believed to be mediated, at least in part, though improving platelet function. At least 10 human intervention studies found a consistent and robust beneficial effect of cocoa products on platelet function, but unfortunately all of these studies used only one or two methods to assess platelet function, therefore only getting limited insights into the complex physiological behavior of platelets. In addition, none of these studies assessed potential mechanisms by which flavan-3-ols may inhibit platelet function. Schramm et al. have shown that consumption of chocolate rich in flavan-3-ols and their oligomers (procyanidins) lead to increased production of prostacyclin, a strong platelet inhibitor. This finding has also been observed when aortic endothelial cells are treated with procyanidins in vitro. Thus the stimulation of prostacyclin production in endothelial cells may reflect one pathway by which flavan-3-ols indirectly inhibit platelet activation. Many other potential mechanisms are discussed in the literature but so far the evidence for such mechanisms is limited or non-existing.

In this study we assess effects of consumption of chocolate enriched in flavan-3-ols on platelet function by measuring not only platelet aggregation, but also in vitro coagulation and platelet activation in healthy humans. In addition, we examine the effects of consumption of flavan-3-ols on the regulation of the platelet proteome to elucidate pathways by which these bioactive cocoa compounds affect platelet function.

HYPOTHESIS

Acute consumption of a moderate amount of dark chocolate enriched in flavan-3-ols results in decreased platelet activation and aggregation by decreasing the levels of thromboxane A2 produced by endothelial cells.

OBJECTIVES

The main objective of the proposed study is to determine whether consumption of 60 g dark chocolate enriched in flavan-3-ols results in decreased platelet activation and aggregation by decreasing levels of thromboxane A2, as well as assessing what other mechanisms could be involved.

The specific objectives of the proposed study are to determine:

1. whether acute intake of 60 g dark chocolate enriched in flavan-3-ols, as compared with standard dark chocolate low in flavan-3-ols and white chocolate containing no flavan-3-ols, affects platelet aggregation, thromboxane A2 formation upon aggregation, in vitro bleeding time, P-selectin expression, and activation of the fibrinogen receptor;
2. whether and how acute intake of 60 g dark chocolate enriched in flavan-3-ols, as compared with standard dark chocolate and white chocolate, affects the platelet proteome, and thereby potential new biomarkers of platelet function, as well as protein levels of anti-oxidant enzymes;
3. identities and concentrations of flavan-3-ols and their metabolites in plasma and/ or urine 2 and 6 h after acute intake of 60 g dark chocolate enriched in flavan-3-ols, as compared with standard dark chocolate and white chocolate.

Conditions

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Cardiovascular Disease

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

CROSSOVER

Primary Study Purpose

PREVENTION

Blinding Strategy

SINGLE

Investigators

Study Groups

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42 healthy volunteers - crossover

Acute consumption of three interventions (60 g dark chocolate enriched in flavan-3-ols, 60 g standard dark chocolate, or 60 g white chocolate) on three separate days (at least 2 weeks apart) in random order.

Post-prandial measurements at t = 0 h, t = 2 h and t = 6 h.

Group Type EXPERIMENTAL

Dark chocolate enriched in flavan-3-ols and procyanidins

Intervention Type DIETARY_SUPPLEMENT

Acute consumption (within 15 minutes) of 60 g of chocolate containing \~900 mg of total flavan-3-ols and procyanidins.

Standard dark chocolate

Intervention Type DIETARY_SUPPLEMENT

Acute consumption (within 15 minutes) of 60 g of chocolate containing \~400 mg total flavan-3-ols and procyanidins.

White chocolate

Intervention Type DIETARY_SUPPLEMENT

Acute consumption (within 15 minutes) of 60 g of white chocolate containing no flavan-3-ols and procyanidins.

Interventions

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Dark chocolate enriched in flavan-3-ols and procyanidins

Acute consumption (within 15 minutes) of 60 g of chocolate containing \~900 mg of total flavan-3-ols and procyanidins.

Intervention Type DIETARY_SUPPLEMENT

Standard dark chocolate

Acute consumption (within 15 minutes) of 60 g of chocolate containing \~400 mg total flavan-3-ols and procyanidins.

Intervention Type DIETARY_SUPPLEMENT

White chocolate

Acute consumption (within 15 minutes) of 60 g of white chocolate containing no flavan-3-ols and procyanidins.

Intervention Type DIETARY_SUPPLEMENT

Other Intervention Names

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CocoanOX12%-containing chocolate

Eligibility Criteria

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Inclusion Criteria

* Healthy male and/or female volunteers, aged between 18 and 70 years

Exclusion Criteria

Subjects are excluded if:

* they are taking aspirin or aspirin-containing drugs, other anti-inflammatory drugs, or any drugs or herbal medicines known to alter platelet function or the haemostatic system in general (without a minimum washout period of one month)
* they are taking fish oils or evening primrose oil, or fat soluble vitamin supplements within the last 4 weeks
* they are taking any medicine known to affect lipid and/or glucose metabolism
* they are taking hormone replacement therapy
* they have any known clinical signs of diabetes, hypertension, renal, hepatic, hematological disease, gastrointestinal disorders, endocrine disorders, coronary heart disease, infection or cancer
* they are suffering from alcohol or any other substance abuse or are having eating disorders
* they are usually consuming a vegetarian diet
* they have a BMI below 18 or above 35 kg/ sqm
* they are undertaking more than 6 hours of vigorous exercise per week
* they are having an abnormal menstrual cycle
* they are pregnant
* they suffer from an allergy to cocoa or any of the ingredients contained within either of the chocolate bars
* they have been giving a pint of blood for transfusion purposes within the last month
* they have a low platelet count (\< 170 x 10E09/ L)
* they have unsuitable veins for blood sampling and/ or cannulation
* their hematocrit is below 40 % for males and 35 % for females
* their haemoglobin is below 130 g/ L for males and 115 g/ L for females
* they are not able to travel on their own to the Rowett Institute of Nutrition and Health, Aberdeen for each of the interventions
Minimum Eligible Age

18 Years

Maximum Eligible Age

70 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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Rural and Environment Research and Analysis Directorate (RERAD, UK)

UNKNOWN

Sponsor Role collaborator

Biotechnology and Biological Sciences Research Council

OTHER

Sponsor Role collaborator

Natraceutical Industrial S.L.U., Valencia, Spain

UNKNOWN

Sponsor Role collaborator

University of Aberdeen

OTHER

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Principal Investigators

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Baukje de Roos, MSc PhD

Role: PRINCIPAL_INVESTIGATOR

University of Aberdeen Rowett Institute of Nutrition and Health

Locations

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University of Aberdeen Rowett Institute of Nutrition and Health

Aberdeen, Aberdeenshire, United Kingdom

Site Status

Countries

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United Kingdom

References

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Baba S, Osakabe N, Yasuda A, Natsume M, Takizawa T, Nakamura T, Terao J. Bioavailability of (-)-epicatechin upon intake of chocolate and cocoa in human volunteers. Free Radic Res. 2000 Nov;33(5):635-41. doi: 10.1080/10715760000301151.

Reference Type BACKGROUND
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Bordeaux B, Yanek LR, Moy TF, White LW, Becker LC, Faraday N, Becker DM. Casual chocolate consumption and inhibition of platelet function. Prev Cardiol. 2007 Fall;10(4):175-80. doi: 10.1111/j.1520-037x.2007.06693.x.

Reference Type BACKGROUND
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de Roos B, Duthie SJ, Polley AC, Mulholland F, Bouwman FG, Heim C, Rucklidge GJ, Johnson IT, Mariman EC, Daniel H, Elliott RM. Proteomic methodological recommendations for studies involving human plasma, platelets, and peripheral blood mononuclear cells. J Proteome Res. 2008 Jun;7(6):2280-90. doi: 10.1021/pr700714x. Epub 2008 May 20.

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Flammer AJ, Hermann F, Sudano I, Spieker L, Hermann M, Cooper KA, Serafini M, Luscher TF, Ruschitzka F, Noll G, Corti R. Dark chocolate improves coronary vasomotion and reduces platelet reactivity. Circulation. 2007 Nov 20;116(21):2376-82. doi: 10.1161/CIRCULATIONAHA.107.713867. Epub 2007 Nov 5.

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Hermann F, Spieker LE, Ruschitzka F, Sudano I, Hermann M, Binggeli C, Luscher TF, Riesen W, Noll G, Corti R. Dark chocolate improves endothelial and platelet function. Heart. 2006 Jan;92(1):119-20. doi: 10.1136/hrt.2005.063362. No abstract available.

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Hubbard GP, Wolffram S, de Vos R, Bovy A, Gibbins JM, Lovegrove JA. Ingestion of onion soup high in quercetin inhibits platelet aggregation and essential components of the collagen-stimulated platelet activation pathway in man: a pilot study. Br J Nutr. 2006 Sep;96(3):482-8.

Reference Type BACKGROUND
PMID: 16925853 (View on PubMed)

Hubbard GP, Wolffram S, Lovegrove JA, Gibbins JM. Ingestion of quercetin inhibits platelet aggregation and essential components of the collagen-stimulated platelet activation pathway in humans. J Thromb Haemost. 2004 Dec;2(12):2138-45. doi: 10.1111/j.1538-7836.2004.01067.x.

Reference Type BACKGROUND
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Reference Type BACKGROUND
PMID: 12944249 (View on PubMed)

Mavrommatis Y, O'Kennedy N, de Roos B et al. Effect of eicosapentaenoic acid or docosahexaenoic acid intervention on platelet aggregation: does soluble epoxide hydrolase play a role? unpublished, 2010

Reference Type BACKGROUND

Murphy KJ, Chronopoulos AK, Singh I, Francis MA, Moriarty H, Pike MJ, Turner AH, Mann NJ, Sinclair AJ. Dietary flavanols and procyanidin oligomers from cocoa (Theobroma cacao) inhibit platelet function. Am J Clin Nutr. 2003 Jun;77(6):1466-73. doi: 10.1093/ajcn/77.6.1466.

Reference Type BACKGROUND
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Natella F, Nardini M, Belelli F, Pignatelli P, Di Santo S, Ghiselli A, Violi F, Scaccini C. Effect of coffee drinking on platelets: inhibition of aggregation and phenols incorporation. Br J Nutr. 2008 Dec;100(6):1276-82. doi: 10.1017/S0007114508981459. Epub 2008 Apr 28.

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Ostertag LM, O'Kennedy N, Kroon PA, Duthie GG, de Roos B. Impact of dietary polyphenols on human platelet function--a critical review of controlled dietary intervention studies. Mol Nutr Food Res. 2010 Jan;54(1):60-81. doi: 10.1002/mnfr.200900172.

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Pearson DA, Paglieroni TG, Rein D, Wun T, Schramm DD, Wang JF, Holt RR, Gosselin R, Schmitz HH, Keen CL. The effects of flavanol-rich cocoa and aspirin on ex vivo platelet function. Thromb Res. 2002 May 15;106(4-5):191-7. doi: 10.1016/s0049-3848(02)00128-7.

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Schewe T, Sadik C, Klotz LO, Yoshimoto T, Kuhn H, Sies H. Polyphenols of cocoa: inhibition of mammalian 15-lipoxygenase. Biol Chem. 2001 Dec;382(12):1687-96. doi: 10.1515/BC.2001.204.

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Schramm DD, Wang JF, Holt RR, Ensunsa JL, Gonsalves JL, Lazarus SA, Schmitz HH, German JB, Keen CL. Chocolate procyanidins decrease the leukotriene-prostacyclin ratio in humans and human aortic endothelial cells. Am J Clin Nutr. 2001 Jan;73(1):36-40. doi: 10.1093/ajcn/73.1.36.

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Wang-Polagruto JF, Villablanca AC, Polagruto JA, Lee L, Holt RR, Schrader HR, Ensunsa JL, Steinberg FM, Schmitz HH, Keen CL. Chronic consumption of flavanol-rich cocoa improves endothelial function and decreases vascular cell adhesion molecule in hypercholesterolemic postmenopausal women. J Cardiovasc Pharmacol. 2006;47 Suppl 2:S177-86; discussion S206-9. doi: 10.1097/00005344-200606001-00013.

Reference Type BACKGROUND
PMID: 16794456 (View on PubMed)

Other Identifiers

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09/002

Identifier Type: OTHER

Identifier Source: secondary_id

600

Identifier Type: -

Identifier Source: org_study_id

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