Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Review
. 2023 Jan 10:9:1084455.
doi: 10.3389/fnut.2022.1084455. eCollection 2022.

The effects of green tea supplementation on cardiovascular risk factors: A systematic review and meta-analysis

Mohammad Zamani  1 , Mahnaz Rezaei Kelishadi  2 , Damoon Ashtary-Larky  3 , Niusha Amirani  4 , Kian Goudarzi  5 , Iman Attackpour Torki  6 , Reza Bagheri  7 , Matin Ghanavati  8 , Omid Asbaghi  9   10
Affiliations
Review

The effects of green tea supplementation on cardiovascular risk factors: A systematic review and meta-analysis

Mohammad Zamani et al. Front Nutr. .

Abstract

Purpose: A bulk of observational studies have revealed the protective role of green tea supplementation in cardiovascular diseases. The current systematic review and meta-analysis study aimed to establish the effects of green tea supplementation on cardiovascular risk factors including lipid profile, blood pressure, glycemic control markers and CRP.

Methods: A systematic literature search of randomized clinical trials (RCTs) that investigated the effects of green tea supplementation and cardiovascular risk factors was undertaken in online databases including PubMed/Medline, Scopus, Web of Science, and Embase using a combination of green tea and cardiovascular risk factors search terms. Meta-analyses were carried out using a random-effects model. The I2 index was used to assess the heterogeneity of RCTs.

Results: Among the initial 11,286 studies that were identified from electronic databases search, 55 eligible RCTs with 63 effect sizes were eligible. Results from the random effects meta-analysis showed that GTE supplementation significantly reduced TC (WMD = -7.62; 95% CI: -10.51, -4.73; P = < 0.001), LDL-C (WMD = -5.80; 95% CI: -8.30, -3.30; P = < 0.001), FBS (WMD = -1.67; 95% CI: -2.58, -0.75; P = < 0.001), HbA1c (WMD = -0.15; 95% CI: -0.26, -0.04; P = 0.008), DBP (WMD = -0.87; 95% CI: -1.45, -0.29; P = 0.003), while increasing HDL-C (WMD = 1.85; 95% CI: 0.87, 2.84; P = 0.010). Subgroup analyses based on the duration of supplementation (≥ 12 vs. < 12 weeks), dose of green tea extract (GTE) (≥1,000 vs. < 1,000 mg/d), sex (male, female, and both), baseline serum levels of lipid profile, and glycemic control factors demonstrated different results for some risk factors.

Conclusion: The current study suggests improvements in the lipid and glycemic profiles following green tea supplementation. These findings support previous evidence showing the health benefits of green tea supplementation on cardiometabolic risk factors.

Keywords: blood pressure; cardiovascular risk factors; glycemic control; green tea supplementation; lipid profile; meta-analysis; systematic review.

PubMed Disclaimer

Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

FIGURE 1
FIGURE 1
Flow chart of study selection for inclusion trials in the systematic review.
FIGURE 2
FIGURE 2
Forest plot detailing weighted mean difference and 95% confidence intervals (CIs) for the effects of green tea extract supplementation on (A) TG (mg/dL); (B) TC (mg/dL); (C) LDL (mg/dL); (D) HDL (mg/dL); (E) FBS (mg/dL); (F) fasting insulin (μlU/ml); (G) HbA1c (%); (H) HOMA-IR; (I) SBP (mmHg), (J) DBP (mmHg); (K) CRP (mg/dL).
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Abe S, Inoue M. Green tea and cancer and cardiometabolic diseases: a review of the current epidemiological evidence. Eur J Clin Nutr. (2021) 75:865–76. 10.1038/s41430-020-00710-7 - DOI - PMC - PubMed
    1. Khan N, Mukhtar H. Tea polyphenols for health promotion. Life Sci. (2007) 81:519–33. 10.1016/j.lfs.2007.06.011 - DOI - PMC - PubMed
    1. Chacko S, Thambi P, Kuttan R, Nishigaki I. Beneficial effects of green tea: a literature review. Chin Med. (2010) 5:13. 10.1186/1749-8546-5-13 - DOI - PMC - PubMed
    1. Lorenzo J, Munekata P. Phenolic compounds of green tea: health benefits and technological application in food. Asian Pac J Trop Biomed. (2016) 6:709–19. 10.1016/j.foodres.2017.11.047 - DOI - PubMed
    1. Musial C, Kuban-Jankowska A, Gorska-Ponikowska M. Beneficial properties of green tea catechins. Int J Mol Sci. (2020) 21:1744. 10.3390/ijms21051744 - DOI - PMC - PubMed