Could tea consumption decrease the risk of depression: A systematic review and meta-analysis?

Depression is a chronic and overwhelming disorder. One of the factors that could prevent the occurrence of depression is tea consumption. Considering the controversial results of previous studies, the aim of this systematic and meta-analysis review study was to answer this question that whether tea consumption could decrease the risk of depression.
Methods & Materials: By searching the keywords of tea, depressive disorder, depression caffeine, theanine and polyphenols in national and international databases such as SID, MagIran, Google Scholar, IranMedex, Science Direct, Pubmed, ProQuest and Scopus from 2000 to 2016, 12 descriptive and cross-sectional studies about the relation between tea and depression were extracted. Data of the selected studies were analyzed by meta-analysis method and random model effect. Heterogeneity of the studies was evaluated using I2 index. Data were analyzed using STATA 11.2 software.
The sample size of the present study included 629910 participants with an average of 52493 participants for each study. Results of the present study showed a significant relation between tea consumption and symptoms of depression (95%CI:0.50-0.84, OR = 0.65); in a way that the risk of depression among participants who consumed tea was 35% lower than those who did not consume tea.
Results of the present study revealed that tea consumption would decrease the risk of depression. Considering the high consumption of tea all around the world and the high prevalence of depression, balance daily tea consumption is recommended as a method for preventing depression