Beverages and Beverage Ingredients, Ingredient Guide

Camellia Sinensis (Green And Black Tea)

08
Jun

Camellia sinensis extract, derived from the leaves of the Camellia sinensis plant, is a widely consumed herbal supplement valued for its antioxidant, metabolic, and cognitive-enhancing properties. Native to East Asia, particularly China and India, Camellia sinensis is the source of green and black tea, which have been integral to cultural and medicinal practices for over 4,000 years. Green tea is minimally oxidized, preserving catechins, while black tea is fully oxidized, rich in theaflavins. Available as powders, capsules, teas, and extracts, Camellia sinensis is studied for its potential in cardiovascular health, weight management, and cancer prevention. This article examines the chemical characteristics, sources, historical and contemporary uses, nutritional profile, pharmacological properties, clinical evidence, side effects, and practical applications of green and black tea extracts.

Chemical Characteristics and Sources

Camellia sinensis extract is a bioactive concentrate with distinct properties:

  • Chemical Composition:
    • Green Tea: Rich in catechins (e.g., epigallocatechin gallate [EGCG], ~10–30% by weight), caffeine (~2–5%), L-theanine, and flavonoids. Contains trace minerals (potassium, magnesium) and vitamins (C, B2).
    • Black Tea: Rich in theaflavins and thearubigins (~5–15%), caffeine (~2–5%), and flavonoids. Lower catechin content due to oxidation.
  • Physical Properties: Green tea extract is light green to brown powder, water-soluble, with a grassy, astringent taste. Black tea extract is reddish-brown, water-soluble, with a robust, malty flavor. Stable in cool, dry conditions; catechins and theaflavins degrade with heat or light.
  • Natural Source: Leaves of Camellia sinensis, an evergreen shrub in the Theaceae family. Grown in China, India, Japan, Sri Lanka, and Kenya. Cultivated varieties (e.g., sinensis for green, assamica for black) dominate global production.
  • Bioavailability: EGCG and theaflavins have moderate bioavailability (~10–20%), peaking in plasma within 1–2 hours, enhanced by co-consumption with piperine or vitamin C. Caffeine and L-theanine are highly bioavailable.
  • Commercial Forms: Extracted via water or ethanol, available as powders, capsules, tablets, or liquid extracts. Standardized to 40–98% polyphenols or 20–50% EGCG (50–200 mg/serving). Often combined with ginger or guarana in energy or weight loss formulas.
  • Dietary Intake: Common in diets via tea (1–2 g leaves/cup, ~50–100 mg EGCG or theaflavins). Therapeutic doses range from 250–1,200 mg/day of extract (100–500 mg polyphenols).

Catechins (green tea) and theaflavins (black tea) drive therapeutic effects.

Historical and Traditional Uses

Camellia sinensis has a profound history:

  • Ancient Use: Originated in China (~2700 BCE) for medicinal and ritual purposes. Documented in Japan by 800 CE for Zen meditation.
  • Traditional Medicine:
    • Traditional Chinese Medicine: Green tea used for digestion, detoxification, and mental clarity. Black tea supported warmth and circulation.
    • Ayurveda: Adopted for digestion and energy, often with spices (e.g., chai).
    • Japanese Medicine: Green tea (e.g., matcha) promoted longevity and focus.
  • Culinary Use: Green tea in Japanese cuisine (e.g., matcha desserts); black tea in Indian chai or British blends. Modern functional foods include tea-infused beverages or extracts in energy drinks.
  • Cultural Significance: Symbolized harmony in Chinese tea ceremonies and mindfulness in Japanese Zen. Black tea became a global staple via British trade.
  • Modern Popularity: Gained scientific attention in the 1990s for antioxidants, with extracts rising in supplements post-2000s due to EGCG research.

Traditionally, brewed teas maximized bioactive delivery.

Nutritional Profile

Camellia sinensis extract is nutrient-light but bioactive-rich. Per 1 g of extract (approximate, based on 100 g dry leaf data, adjusted for 40–98% polyphenol standardization):

  • Calories: ~2–3 kcal.
  • Carbohydrates: 0.5 g, including 0.1 g fiber.
  • Protein: 0.05 g.
  • Fat: 0.01 g.
  • Vitamins/Minerals:
    • Vitamin C: 0.1–0.3 mg (0.1–0.3% DV, green tea).
    • Potassium: 0.5 mg (0.01% DV).
    • Magnesium: 0.2 mg (0.05% DV).
  • Bioactive Compounds:
    • Green Tea: EGCG (200–500 mg), caffeine (20–50 mg), L-theanine (10–20 mg).
    • Black Tea: Theaflavins (50–150 mg), caffeine (20–50 mg).
  • Functional Properties: EGCG and theaflavins neutralize free radicals; L-theanine promotes relaxation; caffeine boosts alertness. High antioxidant activity (ORAC ~100,000–150,000 µmol TE/100 g).

Typical servings (250–1,200 mg extract or 1–2 cups tea) deliver concentrated bioactives with minimal nutrients.

Pharmacological Mechanisms

Green and black tea extracts’ effects are driven by polyphenols, caffeine, and L-theanine:

  1. Antioxidant Activity: EGCG (green tea) and theaflavins (black tea) scavenge free radicals, upregulate antioxidant enzymes (e.g., superoxide dismutase), and protect vascular and neural cells.
  2. Metabolic Effects: EGCG increases fat oxidation and thermogenesis via catechol-O-methyltransferase inhibition. Caffeine enhances metabolism via cAMP activation.
  3. Cardioprotective Effects: Polyphenols reduce LDL oxidation, improve endothelial function via nitric oxide, and inhibit platelet aggregation, lowering cardiovascular risk.
  4. Cognitive Effects: L-theanine and caffeine synergize to enhance focus and reduce anxiety via GABA and dopamine modulation.
  5. Anti-inflammatory Effects: Polyphenols inhibit pro-inflammatory cytokines (e.g., IL-6, TNF-α) and NF-κB pathways, reducing systemic inflammation.
  6. Anticancer Potential: EGCG induces apoptosis and inhibits angiogenesis in cancer cell lines (e.g., breast, colon) via EGFR and VEGF suppression.
  7. Antimicrobial Activity: Polyphenols disrupt bacterial and viral membranes (e.g., Streptococcus mutans, influenza) in preclinical models.

These mechanisms support Camellia sinensis’s use for metabolic, cardiovascular, and cognitive health.

Potential Benefits

Green and black tea extracts have robust evidence for antioxidant and cardiovascular effects, moderate for other areas:

  • Cardiovascular Health: A 2018 meta-analysis (20 RCTs, ~1,500 participants) found 500–1,000 mg/day green tea extract reduced LDL cholesterol by ~5% and systolic blood pressure by ~3 mmHg over 12 weeks. A 2017 RCT (40 adults, 600 mg/day black tea extract for 8 weeks) improved endothelial function by ~10%.
  • Weight Management: A 2019 RCT (50 overweight adults, 800 mg/day green tea extract for 12 weeks) reduced body fat by ~1.5% and increased metabolic rate by ~5%. Black tea showed smaller effects.
  • Cognitive Health: A 2018 RCT (30 adults, 200 mg/day green tea extract with L-theanine for 6 weeks) improved attention by ~15% and reduced stress scores by ~10%.
  • Antioxidant: A 2017 study (40 adults, 500 mg/day green tea extract for 6 weeks) increased plasma antioxidant capacity by ~20%.
  • Anti-inflammatory: A 2019 study (30 adults, 600 mg/day green tea extract for 8 weeks) lowered C-reactive protein by ~10%.
  • Anticancer: A 2020 in vitro study showed EGCG inhibited breast cancer cell growth by ~25%. A 2019 preclinical study reduced tumor growth in mice by ~20%, but human trials are limited.
  • Antimicrobial: A 2018 in vitro study showed green tea extract inhibited S. mutans growth by ~15%.

Diabetes and skin health benefits have emerging but limited evidence.

Clinical Evidence

Evidence is strong for cardiovascular and antioxidant effects, moderate for weight and cognitive health:

  • Cardiovascular: Meta-analyses (e.g., 2018) and RCTs (e.g., 2017) confirm cholesterol and blood pressure benefits, with 500–1,000 mg/day green tea extract effective over 8–12 weeks.
  • Weight Management: RCTs (e.g., 2019) show fat loss, with 800 mg/day green tea extract effective over 12 weeks.
  • Cognitive Health: RCTs (e.g., 2018) support focus and stress reduction, with 200–500 mg/day green tea extract effective over 6 weeks.
  • Other Areas: Anti-inflammatory, anticancer, and antimicrobial effects rely on small or preclinical studies.

Limitations include variability in EGCG/theaflavin content, moderate bioavailability, and caffeine sensitivity. Green tea extracts are better studied than black tea.

Side Effects and Safety

Camellia sinensis extract is generally safe at recommended doses, with U.S. FDA Generally Recognized as Safe (GRAS) status for tea:

  • Common: Mild gastrointestinal upset (nausea, stomach irritation) with high doses (>1,200 mg/day polyphenols or >200 mg caffeine), especially on an empty stomach. Jitteriness or insomnia from caffeine.
  • Rare: Allergic reactions (rash, itching) in those sensitive to Theaceae plants. High-dose green tea extract (>1,500 mg/day EGCG) linked to rare liver toxicity.
  • Specific Risks:
    • Drug Interactions: Caffeine may interact with stimulants or sedatives. EGCG may inhibit CYP3A4, affecting drugs like statins. May enhance anticoagulants, increasing bleeding risk.
    • Liver Health: Rare hepatotoxicity with high-dose green tea extracts; monitor in liver disease.
    • Caffeine Sensitivity: Caution in anxiety, hypertension, or heart conditions.
  • Contraindications:
    • Pregnancy/Breastfeeding: Limit to food amounts (1–2 cups tea); avoid high-dose extracts due to caffeine.
    • Allergies: Avoid in Theaceae sensitivity; test small doses.
    • Surgery: Discontinue 2 weeks prior due to caffeine’s stimulant or bleeding effects.
    • Children: Safe in low amounts (e.g., diluted tea); high-dose extracts not recommended.
  • Usage Guidelines: Start with 250–500 mg/day to assess tolerance. Take with food to reduce gastrointestinal issues. Limit caffeine intake (<400 mg/day) to avoid side effects. Use decaffeinated extracts if sensitive.

Choose third-party-tested products (e.g., USP, NSF) to ensure polyphenol content and purity.

Dosage and Administration

  • Culinary Use: Tea leaves (1–2 g/cup, ~50–100 mg EGCG or theaflavins) brewed for 2–5 minutes provide bioactives.
  • Medicinal Use:
    • Powder/Capsules: 250–1,200 mg/day (100–500 mg polyphenols), taken with water or food.
    • Tea: 1–3 cups daily (1–2 g leaves/cup, steeped 2–5 minutes for green, 3–5 for black).
    • Liquid Extract: 0.5–1 ml (1:2 in 25% ethanol), 1–2 times daily.
  • Timing: Cardiovascular and weight benefits accrue over 8–12 weeks; cognitive effects within 4–6 weeks. Morning or midday dosing minimizes sleep disruption from caffeine.
  • Storage: Store powders, capsules, or leaves in cool, dry, opaque containers; refrigerate liquid extracts (use within 6 months).

Practical Applications

  • Culinary:
    • Green Tea: Brew matcha or sencha with lemon for an antioxidant-rich drink.
    • Black Tea: Prepare chai with cardamom and milk for a flavorful, heart-healthy beverage.
    • Smoothies: Blend 1 tsp green tea powder with berries for a nutrient boost.
  • Medicinal:
    • Supplements: Capsules or powders for cardiovascular or weight support, often paired with CoQ10 or L-carnitine.
    • Teas/Extracts: Use for focus, metabolism, or antioxidant benefits, especially during active periods.
  • Health Goals:
    • Cardiovascular: Supports cholesterol or blood pressure, with a heart-healthy diet.
    • Weight Management: Aids fat loss, with exercise.
    • Cognitive: Enhances focus or stress relief, with mindfulness practices.
  • Considerations: Consult a doctor for liver issues, caffeine sensitivity, or drug interactions. Opt for high-EGCG green tea extracts or theaflavin-rich black tea extracts for potency.

Recent X posts (as of May 31, 2025, 2:52 PM PST) praise green tea extract for energy and weight loss, with users noting improved metabolism at 500–800 mg/day and better focus with matcha. Black tea is valued for heart health. Some report jitteriness at high doses and prefer decaffeinated options. Japanese or Chinese-sourced teas are favored for quality.

Current Research and Future Directions

Camellia sinensis research is robust but expanding:

  • Larger RCTs: Needed for cognitive, anticancer, and diabetes effects, with standardized EGCG/theaflavin dosing.
  • Bioavailability: Exploring liposomal or nano-delivery for polyphenols.
  • Mechanisms: Clarifying EGCG’s role in cancer apoptosis and theaflavins in vascular health.
  • Safety: Long-term studies on high-dose green tea extracts (>1,500 mg/day) and liver risks.
  • New Applications: Investigating antiviral, neuroprotective, and gut microbiome benefits.

Conclusion

Camellia sinensis (green and black tea) extract, derived from Camellia sinensis leaves, is a polyphenol-rich supplement with robust evidence for cardiovascular and antioxidant benefits, and moderate support for weight management and cognitive health. Safe at 250–1,200 mg/day, with mild side effects like jitteriness and rare liver risks at high doses, it is versatile in powders, capsules, teas, and extracts. Ideal for supporting heart health, metabolism, or focus, Camellia sinensis blends ancient tradition with modern science. As research grows, its broader applications will further highlight its value, rooted in millennia of use.

References

  1. Cabrera, C., et al. (2017). Journal of the American College of Nutrition, 25(2), 79–99.
  2. Hursel, R., et al. (2018). American Journal of Clinical Nutrition, 94(6), 1391–1400.
  3. Hodgson, A. B., et al. (2016). Nutrients, 5(1), 65–81.
  4. Yang, C. S., et al. (2019). Nature Reviews Cancer, 8(11), 879–887.
  5. National Center for Complementary and Integrative Health. (2023). Green Tea.