GREEN TEA (<i>CAMELLIA SINENSIS</i>) AND COGNITIVE HEALTH: A SYSTEMATIC REVIEW OF MECHANISMS, CLINICAL EVIDENCE, AND NEUROPROTECTIVE POTENTIAL

Cognitive decline, often a precursor to neurodegenerative diseases like Alzheimer's, is a growing global health challenge. Green tea (Camellia sinensis), rich in bioactive compounds such as epigallocatechin-3-gallate (EGCG) and L-theanine, has demonstrated promise in supporting cognitive function and reducing cognitive decline. This systematic review evaluated the recent evidence on the effects of green tea on cognition and its underlying mechanisms. The authors conducted a comprehensive search of PubMed, SpringerLink, and ScienceDirect for open-access articles published between January 2020 and April 2025. This systematic review included studies examining the impact of green tea on cognitive function in humans and animal models. The conduct of data extraction and synthesis in this review aligned with the PRISMA guidelines. This review included 22 studies (14 human and eight animal studies). Green tea consumption was consistently associated with a reduced risk of cognitive decline. Preclinical studies identified neuroprotective mechanisms, including antioxidant, anti-inflammatory, and neurogenic effects. Clinical trials demonstrated improvements in memory, executive function, and mood. The benefits of green tea depend on several factors, including sleep quality, genetic factors, and tea formulation. However, this review noted the variability in study design and the limited long-term trials. Green tea is a promising intervention for cognitive health preservation. To optimize its use in clinical practice, future research should standardize tea formulations, explore genetic and lifestyle factors, and conduct long-term randomized controlled trials to confirm its therapeutic potential.