Green Tea
Important Disclaimer
This is not medical advice. Consult a qualified healthcare provider before using any remedy, especially if pregnant, breastfeeding, on medication, or managing a health condition.
Overview
Green tea is made from the unoxidized leaves of Camellia sinensis, preserving its high concentration of catechins — particularly EGCG — making it one of the most antioxidant-rich beverages in the world. Green tea has been consumed in China and Japan for over 4,000 years and is one of the most extensively studied natural health products, with thousands of peer-reviewed publications supporting its benefits for cardiovascular health, brain function, metabolism, and cancer prevention.
Traditional Use
Green tea has been consumed in China for over 4,000 years. In traditional Chinese medicine, green tea is used to clear heat, promote digestion, improve mental alertness, and as a diuretic. Japanese tea culture (Chado) developed around green tea, with matcha becoming central to Zen Buddhist practice for promoting calm alertness during meditation. Traditional uses include treating headaches, digestive complaints, and as a general health tonic.
Key Active Compounds
EGCG (Epigallocatechin Gallate)
The most abundant and potent catechin in green tea. A powerful antioxidant that inhibits cancer cell growth, reduces inflammation, supports cardiovascular health, and enhances fat oxidation.
L-Theanine
A unique amino acid found almost exclusively in tea. Promotes calm alertness by increasing alpha brain waves and modulating GABA, dopamine, and serotonin. Works synergistically with caffeine.
Caffeine
Present at 25–50mg per cup. Provides mild stimulation and works synergistically with L-theanine for sustained, calm focus.
Other Catechins (EGC, ECG, EC)
Additional catechins that contribute to green tea's antioxidant, antimicrobial, and anti-inflammatory properties.
Evidence-Based Benefits
Cardiovascular health
Strong evidenceLarge epidemiological studies and clinical trials show regular green tea consumption reduces LDL cholesterol, blood pressure, and cardiovascular disease risk by 10–31%.
Cognitive function and brain health
Moderate evidenceThe L-theanine and caffeine combination uniquely improves attention, memory, and reaction time. Long-term consumption is associated with reduced risk of Alzheimer's and Parkinson's disease.
Metabolic support and weight management
Moderate evidenceEGCG and caffeine synergistically increase fat oxidation and metabolic rate. Meta-analyses show green tea extract modestly but significantly reduces body weight and waist circumference.
Cancer prevention
Some studiesEpidemiological studies show inverse associations between green tea consumption and risk of several cancers. EGCG inhibits tumor cell proliferation in laboratory studies.
Common Preparation Methods
Traditional Brewed Tea
Heat water to 70–80°C (158–176°F) — not boiling. Steep 1 teaspoon of loose leaf green tea or 1 tea bag for 2–3 minutes. Strain and drink.
Dosage: 3–5 cups dailyDo not use boiling water — it destroys catechins and makes tea bitter.
Matcha Preparation
Sift 1–2 teaspoons of matcha powder into a bowl. Add 2–3 oz of 75°C water. Whisk vigorously in a W-motion until frothy.
Dosage: 1–2 servings dailyMatcha contains the whole leaf, providing 3x more EGCG than brewed green tea.
Green Tea Extract Capsules
Take standardized green tea extract capsules (standardized to 50% EGCG) with meals.
Dosage: 400–500mg EGCG dailyTake with food to reduce risk of liver irritation. Do not exceed recommended doses.
Cold Brew Green Tea
Add 2 teaspoons of loose leaf green tea to 1 liter of cold water. Refrigerate for 6–12 hours. Strain and drink.
Dosage: 2–4 cups dailyCold brewing extracts more L-theanine and less caffeine, producing a sweeter, less bitter tea.
Safety & Cautions
Please read carefully before use
Contraindications
- Iron deficiency anemia: catechins reduce iron absorption
- Liver disease: high-dose extracts may cause liver injury
- Caffeine sensitivity: may cause insomnia, palpitations
- Pregnancy: limit to 2 cups daily due to caffeine
Drug Interactions
- Anticoagulants (warfarin): high doses may affect INR
- Iron supplements: take 2 hours apart
- Stimulant medications: additive caffeine effects
- Certain chemotherapy drugs: EGCG may interact
Possible Side Effects
- Insomnia and restlessness (caffeine)
- Digestive upset on empty stomach
- Rare: liver injury with very high-dose extracts
- Staining of teeth with excessive consumption
Special Populations
- Pregnancy: limit to 2 cups daily
- Children: limit caffeine intake
- Iron deficiency: drink between meals
- Liver disease: avoid high-dose extracts
Sources & References
Nutritional Neuroscience
Journal of Nutritional Biochemistry
Quick Reference
Theaceae
Leaves (unoxidized), Buds
Grassy, vegetal, slightly astringent, umami, mildly bitter
Safety First
Always consult with a qualified healthcare provider before starting any new remedy, especially if you have existing health conditions or take medications.