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

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.

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  • Authors+Show Affiliations

    ,

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

    , , , , , ,

    Source

    MeSH

    Adult
    Aged
    Australia
    Blood Pressure
    Blood Pressure Monitoring, Ambulatory
    Body Weight
    Caffeine
    Cardiovascular Diseases
    Diet
    Double-Blind Method
    Female
    Flavonoids
    Heart Rate
    Humans
    Life Style
    Male
    Middle Aged
    Plant Extracts
    Tea

    Pub Type(s)

    Journal Article
    Randomized Controlled Trial
    Research Support, Non-U.S. Gov't

    Language

    eng

    PubMed ID

    23553154

    Citation

    Hodgson, Jonathan M., et al. "Black Tea Lowers the Rate of Blood Pressure Variation: a Randomized Controlled Trial." The American Journal of Clinical Nutrition, vol. 97, no. 5, 2013, pp. 943-50.
    Hodgson JM, Croft KD, Woodman RJ, et al. Black tea lowers the rate of blood pressure variation: a randomized controlled trial. Am J Clin Nutr. 2013;97(5):943-50.
    Hodgson, J. M., Croft, K. D., Woodman, R. J., Puddey, I. B., Fuchs, D., Draijer, R., ... Head, G. A. (2013). Black tea lowers the rate of blood pressure variation: a randomized controlled trial. The American Journal of Clinical Nutrition, 97(5), pp. 943-50. doi:10.3945/ajcn.112.051375.
    Hodgson JM, et al. Black Tea Lowers the Rate of Blood Pressure Variation: a Randomized Controlled Trial. Am J Clin Nutr. 2013;97(5):943-50. PubMed PMID: 23553154.
    * Article titles in AMA citation format should be in sentence-case
    TY - JOUR T1 - Black tea lowers the rate of blood pressure variation: a randomized controlled trial. AU - Hodgson,Jonathan M, AU - Croft,Kevin D, AU - Woodman,Richard J, AU - Puddey,Ian B, AU - Fuchs,Dagmar, AU - Draijer,Richard, AU - Lukoshkova,Elena, AU - Head,Geoffrey A, Y1 - 2013/04/03/ PY - 2013/4/5/entrez PY - 2013/4/5/pubmed PY - 2013/6/19/medline SP - 943 EP - 50 JF - The American journal of clinical nutrition JO - Am. J. Clin. Nutr. VL - 97 IS - 5 N2 - 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. SN - 1938-3207 UR - https://www.unboundmedicine.com/medline/citation/23553154/Black_tea_lowers_the_rate_of_blood_pressure_variation:_a_randomized_controlled_trial_ L2 - https://academic.oup.com/ajcn/article-lookup/doi/10.3945/ajcn.112.051375 DB - PRIME DP - Unbound Medicine ER -