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ID
Source
Health condition
Vascular function; endothelial function; black tea; healthy volunteers; blood flow; blood pressure; hypertension
vaatfunctie; zwarte thee; endotheel; gezonde vrijwilligers; bloeddruk; hypertensie
Sponsors and support
Intervention
Outcome measures
Primary outcome
Mean forearm blood flow response (volume change measured by venous occlusion plethysmography) to intra-arterially administered acetylcholine (i.e. endothelium-independent vasodilation)
Secondary outcome
Mean forearm blood flow response (volume change measured by venous occlusion plethysmography) to intra-arterially administered sodium nitroprusside (i.e. endothelium-dependent vasodilation);
Mean forearm blood flow response (volume change measured by venous occlusion plethysmography) to intra-arterially administered sodium L-NMMA(i.e. nitric oxide-blocker; endothelium-dependent vasoconstriction)
Background summary
Previous research showed that, even small amounts of, black tea lowers blood pressure in healthy people and people with hypertension.
In this study, we will investigate the effects of acute ingestion of black tea to endothelial function by venous occlusion plethysmography in healthy volunteers. We will study the mechanism underlying the blood pressure lowering effects of black tea.
Voorgaand onderzoek heeft laten zien dat zwarte thee de bloeddruk verlaagd, zowel bij gezonden mensen als mensen met een verhoogde bloeddruk. In deze studie willen we de acute effecten van het drinken van zwarte thee onderzoeken met veneuze occlusie plethysmografie bij gezonde vrijwilligers. Op deze manier onderzoeken we het mechanisme dat ter grondslag ligt aan de bloeddrukverlagende effecten van zwarte thee.
Study objective
We hypothesize that black tea ingestion (approximately 530 mg tea polyphenols) in healthy middle-aged humans will lead to a larger mean forearm blood flow response to acetylcholine (i.e. endothelium-dependent vasodilation)
We hypothesize that black tea ingestion (approximately 530 mg tea polyphenols) in healthy middle-aged humans will not change mean forearm blood flow response to sodium nitroprusside (i.e. endothelium-independent vasodilation)
We hypothesize that black tea ingestion (approximately 530 mg tea polyphenols) in healthy middle-aged humans will lead to a larger decline in mean forearm blood flow response to L-NMMA (i.e. nitric oxide-blocker; endothelium-dependent vasoconstriction)
Study design
not applicable; cross-over design
Intervention
ingestion of black tea vs placebo-tea
Dick H.J. Thijssen
Nijmegen 6525 EX
The Netherlands
+31 (0)24 3614222
d.thijssen@fysiol.umcn.nl
Dick H.J. Thijssen
Nijmegen 6525 EX
The Netherlands
+31 (0)24 3614222
d.thijssen@fysiol.umcn.nl
Inclusion criteria
Healthy subjects:
- Males and post-menopausal (> 1 years) females
- Aged >45 and < 75 years
- Body mass index (BMI) between 18.0 and „T35.0 kg
Exclusion criteria
- Regular performance of strenuous exercise/sport of > 2 hours per week
- Current smoker or has stopped smoking less than 6 months before start of study
- Self reported alcohol intake of >21 units/week)
- Established cardiovascular disease
- Diabetes mellitus
- Blood pressure > 160/100 mmHg
- Subjects taking any medication that might affect endothelial function (e.g. but not limited to beta-blockers, ACE-inhibitors, statins, anti-coagulants, anti-depressants, hormone replacement therapy) will be excluded from the study. Subjects who are on stable medication for which there is no indication of an effect on endothelial function, will be allowed to participate.
Design
Recruitment
Followed up by the following (possibly more current) registration
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Other (possibly less up-to-date) registrations in this register
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In other registers
| Register | ID |
|---|---|
| NTR-new | NL4789 |
| NTR-old | NTR4929 |
| Other | : CMO 2014-1264 |