To assess the effect of cocoa-containing drinks either rich in flavanols or rich in flavanols and theobromine on blood pressure in untreated subjects with high normal blood pressure (prehypertension) or grade I hypertension as measured by 24-hours…
ID
Source
Brief title
Condition
- Vascular hypertensive disorders
Synonym
Research involving
Sponsors and support
Intervention
Outcome measures
Primary outcome
Difference in 24-hour ambulatory blood pressure for both cocoa treatments
compared to the placebo treatment.
Secondary outcome
The difference between the placebo treatment arm and the cocoa treatment arms
in:
Augmentation index, central (aortic) blood pressure and pulse wave velocity as
assessed by the Sphygmocor device.
Systemic vascular resistance as assessed by Finapres.
Endothelial function as assessed by Endopat2000
Insulin sensitivity, lipid profile measured with standard laboratory
techniques.
Platelet aggregation and function.
Mood and psychological well-being (via self-report questionnaires)
Background summary
Persons with high-normal blood pressure or prehypertension and grade I
hypertension have an increased risk for cardiovascular disease. According to
current recommendations of the European Society of Hypertension (ESH) persons
with high-normal blood pressure and grade I hypertension with a maximum of 2
additional risk factors and no evidence or history of cardiovascular disease
are aimed at improving life style. However, implementation of these life style
changes (e.g. salt reduction, weight loss) is notoriously difficult. Recent
studies have shown that consumption of dark chocolate may significantly reduce
blood pressure. Therefore dark chocolate might be a possible
non-pharmacological intervention to lower blood pressure in addition to life
style advice. Current trials were only aimed at stage I and II hypertensive
individuals and did not include a real placebo. Moreover, the substance or
substances, responsible for the blood pressure lowering effect of cocoa have
not been fully established. Both flavanols and theobromine have been considered
as substances which may be responsible for the blood pressure lowering effect.
Apart from their blood pressure lowering effect flavanols and theobromine have
been implicated in beneficially altering lipid profile, platelet aggregation
and feeling of well-being.
Study objective
To assess the effect of cocoa-containing drinks either rich in flavanols or
rich in flavanols and theobromine on blood pressure in untreated subjects with
high normal blood pressure (prehypertension) or grade I hypertension as
measured by 24-hours ambulatory blood pressure.
Study design
Randomized double-blind placebo-controlled cross-over trial.
Intervention
Three weeks daily consumption of a cocoa drink rich in flavanols and rich in
theobromine, a cocoa drink rich in flavanols but low in theobromine and a
placebo drink in random order.
Study burden and risks
In total, the study will take 17 weeks to complete. During this period study
participants will be asked to visit the hospital 10 times, with the first visit
lasting approximately 30 minutes, the second 15 minutes visit 3 2 hours visits
5,7,9 approximately 4 hours and visit 4,6,8,10 approximately 10 minutes. At
baseline (after randomisation) and after all three treatment periods fasting
blood samples will be taken, non-invasive central (aortic) blood pressure
measurements, non-invasive endothelial function measurements and 24-hour blood
pressure measurements will be done. The risks associated with this study
consist of the possible side-effects related to the chocolate containing
drinks. These risks are considered low because of the widespread safe use of
chocolate containing products and the close monitoring of study participants
with predefined stop criteria. Clinical trials investigating chocolate
containing foods or food supplements have safely used flavanols and theobromine
in doses exceeding the dose used in this study. The benefits of participating
in this study are the possible blood pressure lowering effects of chocolate
containing drinks.
Meibergdreef 9
1105 AZ Amsterdam
Nederland
Meibergdreef 9
1105 AZ Amsterdam
Nederland
Listed location countries
Age
Inclusion criteria
informed consent
age 40-70 years
men and postmenopausal women
blood pressure 130-159/85-99 mmHg
maximum of 2 risk factors according to ESH 2007 guidelines
BMI > 18 and < 30 g/m2
not on active anti-hypertensive treatment with at least six weeks since last use of antihypertensive medication
haematological and clinical chemical parameters within the normal reference range
willing to restrict daily intake of coffee below 4 cups and to refrain from dark chocolate and to refrain from supplements that contain polyphenols from the screening visit to the end of the study
Exclusion criteria
previous cardiovascular event(s) (stroke, TIA, angina, myocardial infarction, heart failure)
total cholesterol > 8.0 mmol/L
diabetes mellitus, defined as fasting glucose > 7.0 mmol/L or use of glucose lowering drugs
reported alcohol consumption > 28 alcohol units/week
other diseases or oral medication affecting blood pressure
being an employee of the AMC
currently on a medically prescribed diet, or slimming diet
reported intense sporting activities > 10 h/w
being lactose intolerant
Design
Recruitment
Followed up by the following (possibly more current) registration
No registrations found.
Other (possibly less up-to-date) registrations in this register
No registrations found.
In other registers
| Register | ID |
|---|---|
| CCMO | NL24636.018.08 |