Short-Term Tea Consumption Is Not Associated with a Reduction in Blood Lipids or Pressure: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Ebuwa Igho-Osagie; Kelly Cara; Deena Wang; Qisi Yao; Laura P Penkert; Aedin Cassidy; Mario Ferruzzi; Paul F Jacques; Elizabeth J Johnson; Mei Chung; Taylor Wallace

doi:10.1093/jn/nxaa295

Short-Term Tea Consumption Is Not Associated with a Reduction in Blood Lipids or Pressure: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

J Nutr. 2020 Dec 10;150(12):3269-3279. doi: 10.1093/jn/nxaa295.

Authors

Ebuwa Igho-Osagie¹, Kelly Cara^{1

2}, Deena Wang³, Qisi Yao¹, Laura P Penkert^{1

2}, Aedin Cassidy⁴, Mario Ferruzzi⁵, Paul F Jacques⁶, Elizabeth J Johnson⁶, Mei Chung¹, Taylor Wallace^{7

8}

Affiliations

¹ Department of Public Health and Community Medicine, School of Medicine, Tufts University, Boston, MA, USA.
² Friedman School of Nutrition Science and Policy, Tufts University, Boston, MA, USA.
³ D&V Systematic Evidence Review Consulting, LLC, Bronx, NY, USA.
⁴ Department of Nutrition and Preventive Medicine, Norwich Medical School, University of East Anglia, Norwich, United Kingdom.
⁵ Plants for Human Health Institute, North Carolina State University, Kannapolis, NC, USA.
⁶ Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, USA.
⁷ Department of Nutrition and Food Studies, George Mason University, Fairfax, VA, USA.
⁸ Think Healthy Group, Washington, DC, USA.

PMID: 33188386
DOI: 10.1093/jn/nxaa295

Abstract

Background: A recent systematic review of epidemiological evidence suggests that higher amounts of tea intake are associated with lower risks of cardiovascular disease (CVD) incidence and mortality.

Objectives: Our study objective was to assess mechanisms by which tea consumption may influence CVD risks.

Methods: A systematic review and meta-analysis was conducted to investigate the effects of green and/or black tea consumption (≥4 wk) on systolic blood pressure (SBP), diastolic blood pressure (DBP), total cholesterol, LDL cholesterol, HDL cholesterol, and triglyceride (TG) in healthy populations and among at-risk adults (analyzed separately) with metabolic syndrome, prediabetes, and hypercholesterolemia. The Grading of Recommendations Assessment, Development and Evaluation approach was used to rate the strength of evidence (SoE).

Results: A total of 14 unique RCTs which randomly assigned 798 participants to either green tea, black tea, or placebo controls were included in our analyses. Intervention durations ranged from 4 to 24 wk (mean: 7.4 wk). Individual studies were judged as moderate to high quality based on risk of bias assessments. SoE was low to moderate owing to low sample sizes and insufficient power for most included studies to observe changes in the measured CVD biomarkers. Meta-analyses showed no significant effects of tea consumption on SBP, DBP, total cholesterol, LDL cholesterol, HDL cholesterol, and TG in healthy and at-risk adults (i.e., adults with obesity, prediabetes, borderline hypercholesterolemia, and metabolic syndrome).

Conclusions: Short-term (4-24 wk) tea consumption does not appear to significantly affect blood pressure or lipids in healthy or at-risk adults, although the evidence is limited by insufficient power to detect changes in these CVD biomarkers. High-quality RCTs with longer durations and sufficient sample sizes are needed to fully elucidate the effects of tea. This systematic review was registered at www.crd.york.ac.uk/prospero/ as CRD42020134513.

Keywords: Camellia sinensis; blood pressure; cardiovascular diseases; lipids; tea.

Publication types

Meta-Analysis
Research Support, Non-U.S. Gov't
Systematic Review

MeSH terms

Blood Pressure / drug effects*
Drug Administration Schedule
Humans
Lipids / blood*
Tea*

Substances

Lipids
Tea