Mechanisms Underlying the Anti-Depressive Effects of Regular Tea Consumption

Abstract

This article is a comprehensive review of the literature pertaining to the antidepressant effects and mechanisms of regular tea consumption. Meta-data supplemented with recent observational studies were first analyzed to assess the association between tea consumption and depression risk. The literature reported risk ratios (RR) were 0.69 with 95% confidence intervals of 0.62–0.77. Next, we thoroughly reviewed human trials, mouse models, and in vitro experiments to determine the predominant mechanisms underlying the observed linear relationship between tea consumption and reduced risk of depression. Current theories on the neurobiology of depression were utilized to map tea-mediated mechanisms of antidepressant activity onto an integrated framework of depression pathology. The major nodes within the network framework of depression included hypothalamic-pituitary-adrenal (HPA) axis hyperactivity, inflammation, weakened monoaminergic systems, reduced neurogenesis/neuroplasticity, and poor microbiome diversity affecting the gut–brain axis. We detailed how each node has subsystems within them, including signaling pathways, specific target proteins, or transporters that interface with compounds in tea, mediating their antidepressant effects. A major pathway was found to be the ERK/CREB/BDNF signaling pathway, up-regulated by a number of compounds in tea including teasaponin, L-theanine, EGCG and combinations of tea catechins and their metabolites. Black tea theaflavins and EGCG are potent anti-inflammatory agents via down-regulation of NF-κB signaling. Multiple compounds in tea are effective modulators of dopaminergic activity and the gut–brain axis. Taken together, our findings show that constituents found in all major tea types, predominantly L-theanine, polyphenols and polyphenol metabolites, are capable of functioning through multiple pathways simultaneously to collectively reduce the risk of depression.

Metabolome and Transcriptome Analysis Reveals Putative Genes Involved in Anthocyanin Accumulation and Coloration in White and Pink Tea (Camellia sinensis) Flower

“…Tea (Camellia sinensis (L.) O. Kuntze) is the most popular beverage in the world, largely because of its beneficial health attributes [1,2]. Additionally, it is recognized as one of the most central economic crops in China, India and other developing countries, functioning as a powerful driver of poverty reduction in poor mountainous regions and underdeveloped rural economies.…”

Nutritional applications and beneficial health applications of green tea and l‐theanine in some animal species: A review

“…Green tea leaves have many beneficial health activities including anti-inflammatory, anti-carcinogenic, anti-mutagenic, anti-oxidative, anti-microbial and hypolipidaemic effects (Rothenberg & Zhang, 2019;Varilek et al, 2001). There are studies in the literature with reports that catechins of green tea are capable of binding with minerals thereby influencing their metabolism and concentration (Nelson & Poulter, 2004;Zijp, Korver, & from its utilization in humans, green tea has also played a significant role in livestock production such as in dairy, piggery, goatry and poultry industries.…”

Jieyu Anshen Granule, a Chinese Herbal Formulation, Exerts Effects on Poststroke Depression in Rats

“…with a specific proportion interacting with each other to improve therapeutic effects and to reduce toxicities [7,8]. TCM or its major constituents are often used in clinical practice in China for treating depression; for example, polyphenols may show antidepressant effects through normalizing HPA hyperactivity [9]. Jieyu Anshen granules (JY) are a classical TCM with antidepressant activity that have been recognized by the China Food and Drug Administration [10].…”