Format

Send to

Choose Destination
See comment in PubMed Commons below
Am J Clin Nutr. 2013 May;97(5):943-50. doi: 10.3945/ajcn.112.051375. Epub 2013 Apr 3.

Black tea lowers the rate of blood pressure variation: a randomized controlled trial.

Author information

1
School of Medicine and Pharmacology, University of Western Australia, Perth, Australia. jonathan.hodgson@uwa.edu.au

Abstract

BACKGROUND:

Measures of blood pressure variation have been associated with cardiovascular disease and related outcomes. The regular consumption of black tea can lower blood pressure, but its effects on blood pressure variation have yet to be investigated.

OBJECTIVE:

We aimed to assess the effects of black tea consumption on the rate of ambulatory blood pressure variation.

DESIGN:

Men and women (n = 111) with systolic blood pressure between 115 and 150 mm Hg at screening were recruited in a randomized, controlled, double-blind, 6-mo parallel-designed trial designed primarily to assess effects on blood pressure. Participants consumed 3 cups/d of either powdered black tea solids (tea) or a flavonoid-free caffeine-matched beverage (control). The 24-h ambulatory blood pressure level and rate of measurement-to-measurement blood pressure variation were assessed at baseline, day 1, and 3 and 6 mo.

RESULTS:

Across the 3 time points, tea, compared with the control, resulted in lower rates of systolic (P = 0.0045) and diastolic (P = 0.016) blood pressure variation by ~10% during nighttime (2200-0600). These effects, which were immediate at day 1 and sustained over 6 mo, were independent of the level of blood pressure and heart rate. The rate of blood pressure variation was not significantly altered during daytime (0800-2000).

CONCLUSIONS:

These findings indicate that a component of black tea solids, other than caffeine, can influence the rate of blood pressure variation during nighttime. Thus, small dietary changes have the potential to significantly influence the rate of blood pressure variation. This trial was registered at the Australian New Zealand Clinical Trials Registry as ACTR12607000543482.

PMID:
23553154
DOI:
10.3945/ajcn.112.051375
[Indexed for MEDLINE]
Free full text
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire
    Loading ...
    Support Center