HEALTH EFFECTS OF TEA: A COMPREHENSIVE REVIEW

Tea, derived from the leaves of the Camellia sinensis plant, is one of the most widely consumed beverages globally, second only to water. For millennia, it has been revered not only for its cultural significance and sensory appeal but also for its purported medicinal properties. Modern scientific inquiry has increasingly focused on validating these traditional claims, uncovering a complex array of bioactive compounds—most notably polyphenols such as monomeric catechins, theaflavins, and specialized plant extracts—that contribute substantially to human health. This review synthesizes current research on the physiological impacts of tea consumption, exploring its role in chronic disease prevention, metabolic health, and cognitive safety. Crucially, this updated review integrates new human clinical case data on green tea extracts as direct accelerators of tissue regeneration and wound healing, alongside comparative analytical assessments highlighting the superior antioxidant and anti-inflammatory activities of monomeric green tea components over alternative traditional beverages. Furthermore, we compile cutting-edge evidence validating the chemopreventive and adjunctive anticarcinogenic efficacy of regular and nanosized green tea extracts (NanoGTE) and bio-composites. These formulations significantly enhance the therapeutic indices of traditional chemotherapeutic agents (cisplatin, doxorubicin, cyclophosphamide) and polyamine synthesis inhibitors against wild-type and multidrug-resistant tumor models, while simultaneously alleviating chemotherapy-induced nephrotoxicity, cardiotoxicity, and myelosuppression. Molecular mechanisms underpinning these diverse clinical and experimental outputs—including cell re-energization, DNA synthesis support, protein denaturation inhibition, and quantum mechanical tunneling effects—are comprehensively evaluated (Zaletok et al., 2015; Gulua et al., 2024a; Gulua et al., 2024b).