Condition category
Circulatory System
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting

Plain English Summary

Background and study aims
This is a study to investigate the effects of long-term cocoa intake on the cardiovascular health of post-menopausal women as they are known to be at greater risk of cardiovascular disease. Our goal is to investigate if drinking cocoa high in antioxidant compounds called flavonoids will improve your cardiovascular health.

Who can participate?
Post-menopausal women aged between 49 and 65 years.

What does the study involve?
Initially we will ask you questions about your medical history, measure your weight, height, blood pressure, waist and hip circumference. We take a small blood sample to ascertain that your blood chemistry is normal. Providing the blood tests are normal you will then be invited to take part in the study and attend the hospital on a total of four occasions - at the beginning and end of each 6-week period. You will be required to give blood and urine samples and have your arteries scanned at the beginning and end of each 6-week period. You will be randomly allocated to receive either specially made cocoa powder or a dummy (placebo) cocoa powder dissolved in water daily for 6 weeks. There will then be a 4-week break where you do not have to consume any cocoa. After this, you will receive the other cocoa powder to drink daily for 6 weeks.

What are the possible benefits and risks of participating?
There could be benefits from drinking the high antioxidant cocoa. There is a small risk of bruising from giving a blood sample. The scan of the arteries requires placing a tablet (glyceryl trinitrite) under your tongue for 5 minutes before the scan and this may cause some tingling, discomfort or pain.

Where is the study run from?
The study is run from King's College London in collaboration with St Thomas’ Hospital (UK).

When is the study starting and how long is it expected to run for?
August 2006 to February 2007

Who is funding the study?
King's College London (UK) and the cocoa was manufactured and supplied by Mars Inc

Who is the main contact?
Dr Ummezeinab Mulla
Professor Thomas Sanders

Trial website

Contact information



Primary contact

Prof Thomas Sanders


Contact details

150 Stamford Street
Franklin Wilkins Building
King's College London
United Kingdom
+44 (0)20 7848 4273

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

An investigation into the effects of chronic consumption of cocoa flavonoids on vascular function: a randomised controlled trial


Study hypothesis

Cocoa flavonoids lower blood pressure and improve endothelial function.

Ethics approval

King's College London Research Ethics Committee, 04/08/2006

Study design

Randomised controlled trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting


Trial type


Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet


Cardiovascular disease


Subjects were supplied with packets of cocoa powder. They were instructed to take two packets daily for two 6 week periods (dissolved in water) with a break inbetween (minimum of 4 weeks break). Each pack contained 20g of cocoa. The placebo product contained 16 mg of flavonols per packet and the flavonol rich product contained approximately 330 mg of flavonols per packet. Subjects consumed twice this amount per day as they had two packets per day.
There was no follow up once they had finished the study (the two 6 week interventions).

Intervention type



Not Applicable

Drug names

Primary outcome measures

Blood pressure
The outcome measures were taken at the beginning and end of each intervention period.

Secondary outcome measures

Arterial stiffness, flow mediated dilatation, plasma ICAM-1, VCAM-1, C-reactive protein, P-selectin, 8-isoprostane F2 α, lipids and urinary 8-isoprostane F2

Overall trial start date


Overall trial end date


Reason abandoned


Participant inclusion criteria

Non-smoking postmenopausal women aged between 48 and 65 years

Participant type


Age group




Target number of participants


Participant exclusion criteria

1. Current smokers were excluded due to confounding influences of smoking on measurement of endothelial function
2. A reported history of myocardial infarction, angina, venous thrombosis, stroke, diabetes (fasting plasma glucose > 7mmol/L) or invasive cancer in the last five years
3. Recent use of oral hypolipidaemic therapy (in the last three months)
4. Current use of antihypertensive medication
5. Those receiving drugs for regulating haemostasis but excluding aspirin or who have been exposed to any investigational agent within 30 days of the study
6. Presence of gastrointestinal disorder or use of a drug, which is likely to alter gastrointestinal motility or nutrient absorption
7. Alcohol intake exceeding a moderate intake (>28 units per week)
8. Body Mass Index between <20 or >35 kg/m2
9. Blood pressure systolic >160mm Hg or diastolic >100 mm Hg
10. Fasting blood cholesterol >7.8 mmol/l
11. Fasting plasma triacyglycerol concentrations > 3 mmol/l
12. Estimated cardiovascular risk of greater than 20% over the next 10 years using the Framingham algorithm
13. Subjects unable to tolerate chocolate products
14. Dietary supplements other than vitamin and mineral supplement or fish oil (not exceeding 0.45g long chain n-3 fatty acids/d)

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

150 Stamford Street
United Kingdom

Sponsor information


Kings College London (UK)

Sponsor details

c/o Professor Tom Sanders
150 Stamford Street
Franklin Wilkins Building
United Kingdom
+44 (0)20 7848 4273

Sponsor type




Funder type


Funder name

King's College London (UK)

Alternative name(s)

Funding Body Type

Funding Body Subtype


Funder name

Mars Inc. (USA)

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

Not provided at time of registration

Intention to publish date

Participant level data

Not provided at time of registration

Results - basic reporting

Publication summary

Publication citations

Additional files

Editorial Notes

08/08/21016: No publications found in PubMed, verifying study status with principal investigator.