Green Tea: Brewing Better Brainpower
Camellia sinensis
📜Ancient Use:
🏯☸️Ancient China
Green tea originated in China around 2737 BCE, and was reportedly discovered by Emperor Shen Nong when a tea leaf fell into boiling water. 🍃 It was valued for medicinal benefits like digestion, longevity, energy, and headache relief. During the Tang dynasty, Buddhist monks used green tea—especially matcha—to stay alert and enhance focus during meditation. 🧘♂️🍵
🍵⛩️Ancient Japan
Green tea was introduced to Japan by Buddhist monks from China in the 9th century, along with tea ceremonies. By the Muromachi period, matcha drinking became popular among aristocrats and samurai, praised by Zen monks for boosting mental clarity and meditative focus.🎎⚔️
🍵🧠Epigallocatechin Gallate (EGCG) and Its Beneficial Effects on the Brain
EGCG (Epigallocatechin gallate) is a powerful catechin found in green tea, known for its many brain-boosting benefits. Here's how EGCG supports brain health:
1. 🌿⚡Antioxidant and Anti-inflammatory Effects
EGCG neutralizes free radicals to protect brain cells from oxidative damage and reduces neuroinflammation linked to diseases like Alzheimer’s and Parkinson’s.
2. 🛡️🌱Neuroprotection and Neurogenesis
EGCG regulates cell death and inflammation to safeguard neurons, while promoting the growth of new brain cells in the hippocampus, supporting learning and memory.
3.🧠💡 Cognitive Function Enhancement
EGCG boosts working and short-term memory, attention, and mental clarity, enhancing connectivity between brain regions involved in executive function.
4. 🧠💬Neurotransmitter Modulation
EGCG influences dopamine, serotonin, and acetylcholine levels, improving mood and cognitive function, with potential benefits for depression and anxiety.
5.🦠🧠 Alzheimer's and Parkinson’s Disease
EGCG reduces beta-amyloid plaques and prevents alpha-synuclein aggregation, protecting neurons critical in these neurodegenerative diseases.
6. 🔓🧠Blood-Brain Barrier Penetration
EGCG crosses the blood-brain barrier, directly delivering its antioxidant and anti-inflammatory effects to the brain. (1,2)
👨🏽🔬Clinical Trials
🧠 Green Tea & Cognitive Function
A 2020 double-blind, placebo-controlled trial tested daily decaffeinated green tea catechins (336.4 mg) for 12 weeks in 120 adults (50–69 years) with mild cognitive decline (MMSE > 24) (4).
🔍Key Findings:
📉Single Dose: A single dose of GTC significantly reduced incorrect responses on the Continuous Performance Test (CPT), indicating improved attention.
🧠12 Weeks of Daily Intake: Improved response time on working memory tasks (two-back test), suggesting enhanced working memory.
🧠Green Tea (vs. Black Tea & Coffee) & Cognitive Decline
A prospective study of adults aged 60+ explored the relationship between tea and coffee consumption and cognitive decline (5).
🍵Green Tea Consumption & Cognitive Decline
✅ Regular green tea consumption was linked to a lower risk of cognitive decline.
✅ Higher intake correlated with better cognitive function in older adults.☕Black Tea & Coffee
❌ No significant association was found between black tea or coffee consumption and decreased cognitive decline.
🧠In another cross-sectional study of 8,766 adults aged 65 and older without dementia, higher green tea consumption was significantly associated with lower volumes of cerebral white matter lesions—brain changes linked to increased risk of cognitive decline and dementia. Participants who drank about 600 ml (~3 cups) of green tea or more daily had 3–6% fewer lesions compared to low consumers. In contrast, coffee consumption showed no significant association with white matter lesions, hippocampal volume, or total brain volume, highlighting a potentially unique neuroprotective role of green tea🍵 (6).
🧠Green Tea & Alzheimer’s
A cross sectional study of 264 Chinese adults aged 50–70 years, compared green tea consumers to non-consumers. Cognitive function was assessed using cognitive tests and blood biomarkers (7).
🔍Key Findings:
🧠 Cognitive Function Improvement
Green tea drinkers scored higher on cognitive tests (MoCA, HVLT) with better immediate and delayed recall.
📉 Alzheimer’s Disease Prevention
Reduced Alzheimer’s markers (beta-amyloid plaques, tau protein).
🛡️ Antioxidative Stress Benefits
Higher antioxidant enzyme levels (superoxide dismutase, glutathione peroxidase) which neutralize oxidative stress and protect against cellular damage.
🧠Green Tea & Brain Connectivity
A 2014 double-blind study investigated the effects of green tea on brain connectivity during working memory tasks using fMRI (Functional Magnetic Resonance Imaging)(8).
🔗 Enhanced Parieto-Frontal Connectivity:
The fMRI results showed that after consuming green tea extract, there was enhanced connectivity between the parietal and frontal brain regions. These regions are crucial for working memory, attention, and executive functions.
🧠 Working Memory and Cognitive Performance:
The improved connectivity observed on fMRI scans correlated with better performance on the working memory tasks involving attention and short-term memory retention.
⚠️ Safety Considerations for Green Tea Consumption
🥄 Iron Absorption: Tannins in green tea can reduce non-heme iron absorption, risking deficiency—especially for those with low iron or anemia. To reduce this, wait at least 1 hour after meals before drinking green tea.
🏥 Liver Health: High doses of green tea extracts have been linked to liver toxicity. It’s safest to limit intake to 1–5 cups daily and avoid highly concentrated supplements (like green tea extract).
🔑Key Takeaways:
🔬 Green tea improves cognitive function by:
✅ Enhancing attention, working memory, and executive function
✅ Reducing risk of cognitive decline in older adults
✅ Lowering Alzheimer’s-related biomarkers and oxidative stress
✅ Strengthening brain connectivity for improved efficiency
🍵 Overall, green tea shows strong potential as a natural intervention for brain health and cognitive longevity. 🧠
References:
Mokra D, Joskova M, Mokry J. Therapeutic Effects of Green Tea Polyphenol (‒)-Epigallocatechin-3-Gallate (EGCG) in Relation to Molecular Pathways Controlling Inflammation, Oxidative Stress, and Apoptosis. Int J Mol Sci. 2022 Dec 25;24(1):340. doi: 10.3390/ijms24010340. PMID: 36613784; PMCID: PMC9820274.
Pervin M, Unno K, Takagaki A, Isemura M, Nakamura Y. Function of Green Tea Catechins in the Brain: Epigallocatechin Gallate and its Metabolites. Int J Mol Sci. 2019 Jul 25;20(15):3630. doi: 10.3390/ijms20153630. PMID: 31349535; PMCID: PMC6696481.
Mokra D, Joskova M, Mokry J. Therapeutic Effects of Green Tea Polyphenol (‒)-Epigallocatechin-3-Gallate (EGCG) in Relation to Molecular Pathways Controlling Inflammation, Oxidative Stress, and Apoptosis. Int J Mol Sci. 2022 Dec 25;24(1):340. doi: 10.3390/ijms24010340. PMID: 36613784; PMCID: PMC9820274.
Baba Y, Inagaki S, Nakagawa S, Kaneko T, Kobayashi M, Takihara T. Effect of Daily Intake of Green Tea Catechins on Cognitive Function in Middle-Aged and Older Subjects: A Randomized, Placebo-Controlled Study. Molecules. 2020 Sep 17;25(18):4265. doi: 10.3390/molecules25184265. PMID: 32957612; PMCID: PMC7570631.
Noguchi-Shinohara M, Yuki S, Dohmoto C, Ikeda Y, Samuraki M, Iwasa K, Yokogawa M, Asai K, Komai K, Nakamura H, Yamada M. Consumption of green tea, but not black tea or coffee, is associated with reduced risk of cognitive decline. PLoS One. 2014 May 14;9(5):e96013. doi: 10.1371/journal.pone.0096013. PMID: 24828424; PMCID: PMC4020750.
Shibata, S., Noguchi-Shinohara, M., Shima, A. et al. Green tea consumption and cerebral white matter lesions in community-dwelling older adults without dementia. npj Sci Food 9, 2 (2025). https://doi.org/10.1038/s41538-024-00364-w
Zhang R, Zhang L, Li Z, Zhang P, Song H, Yao DA, Cao J, Zhang JJ. Green tea improves cognitive function through reducing AD-pathology and improving anti-oxidative stress capacity in Chinese middle-aged and elderly people. Front Aging Neurosci. 2022 Aug 5;14:919766. doi: 10.3389/fnagi.2022.919766. PMID: 35992609; PMCID: PMC9389233.
Schmidt A, Hammann F, Wölnerhanssen B, Meyer-Gerspach AC, Drewe J, Beglinger C, Borgwardt S. Green tea extract enhances parieto-frontal connectivity during working memory processing. Psychopharmacology (Berl). 2014 Oct;231(19):3879-88. doi: 10.1007/s00213-014-3526-1. Epub 2014 Mar 19. PMID: 24643507; PMCID: PMC4159594.
Images:
https://www.picturethisai.com/care/Camellia_sinensis.html;https://freerangestock.com/photos/117924/green-tea-being-in-traditional-white-cups.html;https://www.pickpik.com/green-tea-white-ceramic-bowl-matcha-power-56736;https://itoldya420.getarchive.net/amp/media/tea-tea-plantation-plants-069c27