Tea, coffee and green tea consumption and mental health outcomes: A systematic review and meta-analysis of observational and intervention studies on stress and related conditions

Abstract

This review aims to examine the effects of tea, coffee, and green tea consumption on human cognitive performance and mental health. Tea, coffee, and green tea are widely consumed beverages worldwide and contain various bioactive compounds that may influence cognitive function and mental health. Research has suggested that caffeine, the primary psychoactive compound in coffee and tea, can improve cognitive function, including attention, alertness, and working memory. The effect of caffeine on cognitive performance may be moderated by individual differences in caffeine metabolism and genetic factors. Green tea contains high levels of catechins, which have been linked to improved cognitive function, such as attention and working memory, as well as reduced risk of cognitive decline and dementia. Theanine, an amino acid found in green tea, has also been associated with relaxation and reduced anxiety. In addition to cognitive performance, tea, coffee, and green tea consumption have been linked to improved mental health outcomes. Research has suggested that coffee consumption may be associated with a lower risk of depression, while green tea consumption has been linked to reduced symptoms of anxiety and stress. However, the evidence regarding the effects of tea, coffee, and green tea on cognitive function and mental health is mixed, and further research is needed to fully understand the potential benefits and risks of these beverages. Additionally, individual differences in caffeine metabolism, genetic factors, and other lifestyle factors may influence the effects of tea, coffee, and green tea on cognitive function and mental health.