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Tea Consumption and Health Outcomes: Umbrella Review of Meta‐Analyses of Observational Studies in Humans
Author(s) -
Yi Mengshi,
Wu Xiaoting,
Zhuang Wen,
Xia Lin,
Chen Yi,
Zhao Rui,
Wan Qianyi,
Du Liang,
Zhou Yong
Publication year - 2019
Publication title -
molecular nutrition and food research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.495
H-Index - 131
eISSN - 1613-4133
pISSN - 1613-4125
DOI - 10.1002/mnfr.201900389
Subject(s) - medicine , observational study , environmental health , meta analysis , consumption (sociology) , coronary artery disease , disease , randomized controlled trial , stroke (engine) , harm , diabetes mellitus , health benefits , gerontology , traditional medicine , endocrinology , psychology , mechanical engineering , social psychology , social science , sociology , engineering
Scope The aim of this article is to conduct an umbrella review to study the strength and validity of associations between tea consumption and diverse health outcomes. Methods and results Meta‐analyses of observational studies examining associations between tea consumption and health outcomes in all human populations and settings are screened. The umbrella review identifies 96 meta‐analyses with 40 unique health outcomes. Tea consumption shows greater benefits than harm to health in this review. Dose–response analyses of tea consumption indicates reduced risks of total mortality, cardiac death, coronary artery disease, stroke, and type 2 diabetes mellitus with increment of two to three cups per day. Beneficial associations are also found for several cancers, skeletal, cognitive, and maternal outcomes. Harmful associations are found for esophageal and gastric cancer when the temperature of intake is more than 55–60 °C. Conclusion Tea consumption, except for very hot tea, seems generally safe at usual levels of intake, with summary estimates indicating the largest reduction for diverse health outcomes at two to three cups per day. Generally, tea consumption seems more beneficial than harmful in this umbrella review. Randomized controlled trials are further needed to understand whether the observed associations are causal.