Can habitual tea drinking be an effective approach against age-related neurodegenerative cognitive disorders: A systematic review and meta-analysis of epidemiological evidence

Abstract

Our present knowledge about the efficacy of tea consumption in improving age-related cognitive disorders is incomplete since previous epidemiological studies provide inconsistent evidence. This unified systematic review and meta-analysis based on updated epidemiological cohort studies and randomized controlled trials (RCTs) evidence aimed to overcome the limitations of previous reviews by examining the efficacy of distinct types of tea consumption. PubMed, Embase, and MEDLINE were searched up to May 20, 2022, and 23 cohorts and 12 cross-sectional studies were included. Random-effects meta-analyses were conducted to obtain pooled RRs or mean differences with 95% CIs. The pooled RRs of the highest versus lowest tea consumption categories were 0.81 (95% CIs: 0.75–0.88) and 0.69 (95% CIs: 0.61–0.77), respectively. The pooled mean difference of four included RCTs revealed a beneficial effect of tea on cognitive dysfunction (MMSE ES: 1.03; 95% CI, 0.14–1.92). Subgroup analyses further demonstrated that green and black tea intake was associated with a lower risk of cognitive disorders in eastern countries, especially in women. The evidence quality was generally low to moderate. The present review provides insight into whether habitual tea consumption can be an effective approach against age-related neurodegenerative cognitive disorders and summarizes potential mechanisms based on currently published literature.

Keywords:

• cognitive disorder
• cognitive impairment
• dementia
• habitual tea drinking
• meta-analysis
• neurodegenerative diseases

Duality of interest

The authors declare that there is no duality of interest associated with this manuscript.

Author contribution

WQ designed the research. WQ and MqL did the literature search. YL and HyZ reviewed studies for inclusion and performed data extraction and checking. WQ and JL performed meta-analyses. WQ, MmZ, and ZyH contributed to the interpretation of data. WQ drafted the article. JC and ZhL contributed to the critical revision of the manuscript for important intellectual content. All authors approved the final manuscript. WQ is the guarantor of this work.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work has been supported by the National Natural Science Foundation of China (Grant No. 32172317; No. 32001680), Changsha Municipal Natural Science Foundation (No. kq2202223), Hunan Provincial Natural Science Foundation of China(2020JJ4351), Major Project of Science and Technology of Guangxi Zhuang Autonomous Region (AA20302018).