Effect of grape seed extract high in polyphenols on blood pressure in subjects with elevated blood pressure levels.

Previous research showed that a grapeseed extract can reduce blood pressure.
The present study will be performed to test, in a second independent study,
whether or not a grapeseed extract has a blood pressure lowering effect. Next
to that, some mechanistic markers will be measured when a blood pressure
lowering effect is seen, which can provide insight into the mechanism of
action.

Primary objective: to study, in subjects with elevated blood pressure levels,
the effects of an encapsulated grape seed extract high in polyphenols on
daytime ambulatory systolic and diastolic blood pressure.
Secondary objective: to explore mechanistic pathways responsible for the blood
pressure lowering efficacy.

- placebo controlled, double blind, randomized parallel design
- 70 subjects
- 2 test products
capsules with grapeseed extract
placebo capsules
- 1 week run-in, 8 weeks intervention
The following measurements will take place at the end of run-in and at the end
of intervention:
Day 1: 12h ambulantory blood pressure measurements (every 20 min)
Day 2: 24h urine collection, 2 blood samples (before and after breakfast)
Day 3: 12h ambulantory blood pressure measurements (every 20 min)
- dietary restrictions during complete study: max 2 cups of tea per day, no red
wine, red grapejuice, dark chocolate, on certain days no alcoholic
consumptions, repetition of meals on measurement days before and after
intervention

Capsules with grapeseed extract
Placebo capsules

There are, as far as known, no medical risks associated with participation to
this study.