Green Tea Extract: Antioxidant Power

What is Green Tea Extract?

Green tea extract is a concentrated form of green tea (Camellia sinensis), containing high levels of polyphenolic compounds, particularly catechins. While green tea has been consumed as a beverage in Asian cultures for over 4,000 years, green tea extract provides these beneficial compounds in a more concentrated, convenient form.

Green tea, black tea, white tea, and oolong tea all come from the same plant - Camellia sinensis. The difference lies in how the leaves are processed. Green tea leaves are minimally processed and not fermented, which preserves the natural polyphenols and gives green tea its characteristic properties.

The History of Green Tea

Green tea originated in China, with legends dating its discovery to 2737 BCE. According to tradition, Emperor Shen Nong discovered tea when leaves from a wild tea tree blew into his pot of boiling water.

Traditional Use in Asian Cultures

For thousands of years, green tea has been consumed in China, Japan, and other Asian countries not just as a beverage, but as part of traditional wellness practices. In traditional Chinese medicine, green tea has been used for various purposes, from supporting digestion to promoting mental clarity.

Japanese Tea Ceremony

In Japan, the preparation and consumption of matcha (powdered green tea) became a spiritual practice known as the Japanese tea ceremony (chanoyu). This ritualized preparation emphasizes mindfulness, respect, and harmony.

Green Tea vs. Green Tea Extract

Brewed Green Tea

A typical cup of brewed green tea (8 oz) contains:

• 50-100mg of polyphenols
• 25-50mg of caffeine
• Various catechins, with EGCG being the most abundant

The exact content varies based on brewing time, water temperature, and tea quality.

Green Tea Extract

Green tea extract is a concentrated form that typically contains:

• 250-500mg of polyphenols per capsule
• Standardized EGCG content (often 45-50% EGCG)
• Variable caffeine content (some extracts are decaffeinated)

This means one capsule of green tea extract can provide the polyphenol content of 2-5 cups of brewed green tea.

Understanding Catechins

Catechins are a type of flavonoid - plant compounds with antioxidant properties. Green tea contains several catechins, with four primary types:

The Four Main Catechins

Epigallocatechin Gallate (EGCG): The most abundant and most studied catechin in green tea, making up approximately 50-80% of total catechins. EGCG is considered the most bioactive compound in green tea.

Epigallocatechin (EGC): The second most abundant catechin, making up approximately 10-20% of total catechins.

Epicatechin Gallate (ECG): Makes up approximately 10-15% of total catechins.

Epicatechin (EC): The least abundant of the four main catechins, at approximately 5-10%.

Total Polyphenol Content

Green tea contains approximately 30-40% polyphenols by dry weight, with catechins making up about 80-90% of total polyphenols. The remaining polyphenols include flavonols, phenolic acids, and other compounds.

EGCG: The Star Compound

Epigallocatechin gallate (EGCG) has been the focus of extensive research due to its potent antioxidant properties.

Antioxidant Capacity

EGCG's antioxidant capacity has been measured using various methods. Research has shown that EGCG's antioxidant power is significantly higher than vitamins C and E in certain assays.

Antioxidants help neutralize free radicals - unstable molecules that can damage cells through a process called oxidative stress. The body naturally produces some free radicals during normal metabolism, but environmental factors like pollution, UV radiation, and poor diet can increase free radical production.

Bioavailability of EGCG

One challenge with EGCG is its relatively low bioavailability - the amount that actually gets absorbed and utilized by the body. Studies have shown that only about 1-5% of ingested EGCG is absorbed in the small intestine.

Factors affecting EGCG absorption:

• Food: Taking green tea extract with food may reduce absorption but can minimize stomach upset
• pH: EGCG is more stable in acidic environments
• Other Compounds: Vitamin C may help stabilize EGCG and enhance absorption
• Gut Bacteria: Intestinal bacteria can metabolize catechins, affecting their bioavailability

Caffeine in Green Tea

Green tea naturally contains caffeine, though less than coffee:

Caffeine Content Comparison

• Brewed Green Tea (8 oz): 25-50mg caffeine
• Brewed Black Tea (8 oz): 40-70mg caffeine
• Brewed Coffee (8 oz): 95-200mg caffeine
• Espresso (1 oz): 47-75mg caffeine

L-Theanine and Caffeine

Green tea contains L-theanine, an amino acid that's rarely found in other foods. L-theanine has a calming effect and may modulate the stimulating effects of caffeine.

Research has examined the combination of L-theanine and caffeine, measuring effects on attention, focus, and mental state. Some studies suggest this combination may provide alertness without the jitters sometimes associated with caffeine alone.

Decaffeinated Green Tea Extract

Many green tea extract supplements are decaffeinated, removing most or all of the caffeine while retaining the catechins. This allows people to get the benefits of green tea polyphenols without caffeine's stimulating effects.

Decaffeination methods include:

• Water processing
• Carbon dioxide extraction
• Ethyl acetate processing

Quality decaffeination preserves most catechins while removing 95-99% of caffeine.

Green Tea Extract Dosage

Research studies have used various dosages of green tea extract:

Common Dosages

General Supplementation: 250-500mg of green tea extract daily, standardized to 45-50% EGCG (providing approximately 112-250mg EGCG).

Higher Doses: Some studies have used 800-1000mg of green tea extract daily, though higher doses increase the risk of side effects.

EGCG-Specific Dosing: Research has used 100-460mg of isolated EGCG daily.

Timing

With Meals: Taking green tea extract with food may reduce the risk of stomach upset, though it may slightly decrease absorption.

Morning/Afternoon: If the extract contains caffeine, avoid taking it late in the day to prevent sleep disruption.

Divided Doses: Some people split their daily dose into 2-3 servings for more consistent blood levels.

Forms of Green Tea Extract

Standardized Extract Capsules

The most common form, standardized to specific percentages of polyphenols and EGCG. Look for products standardized to:

• 50-98% polyphenols
• 45-50% EGCG
• Specified caffeine content (or decaffeinated)

Matcha Powder

Matcha is finely ground whole green tea leaves. Unlike brewed tea where you discard the leaves, with matcha you consume the entire leaf, providing:

• Higher concentration of nutrients
• More fiber
• Complete catechin profile
• Natural caffeine and L-theanine

Matcha contains approximately 3 times the EGCG of regular brewed green tea.

Liquid Extracts

Concentrated liquid forms of green tea extract, often used in smaller doses due to high concentration.

Green Tea in Combination Products

Green tea extract is often included in multi-ingredient formulas combined with other herbs, vitamins, or compounds.

Matcha vs. Regular Green Tea

Matcha deserves special mention as a unique form of green tea:

Cultivation Differences

Matcha tea plants are shade-grown for 20-30 days before harvest. This shading:

• Increases chlorophyll production (giving matcha its vibrant green color)
• Boosts L-theanine content
• Enhances amino acid levels
• Reduces some catechins while concentrating others

Processing Differences

After harvesting, matcha leaves are:

• Steamed to prevent oxidation
• Dried
• Stems and veins removed
• Ground into fine powder using stone mills

Nutritional Differences

Because you consume the whole leaf with matcha:

• Higher antioxidant content per serving
• More fiber
• Higher caffeine (approximately 70mg per serving)
• More L-theanine
• Richer, more complex flavor

Green Tea and Metabolism

Green tea extract has been extensively studied for its effects on metabolism and energy expenditure.

Thermogenesis

Thermogenesis is the process of heat production in the body. Research has measured green tea extract's effects on energy expenditure (calories burned) and fat oxidation (fat burning).

Studies have used various methods to measure these effects:

• Indirect calorimetry (measuring oxygen consumption and CO2 production)
• Respiratory quotient (ratio indicating fuel source being burned)
• 24-hour energy expenditure in metabolic chambers

Research has typically used 250-500mg of green tea extract containing 100-250mg EGCG combined with 50-100mg caffeine.

Catechins and COMT

One proposed mechanism involves catechol-O-methyltransferase (COMT), an enzyme that breaks down catecholamines (like norepinephrine). EGCG may inhibit COMT, potentially prolonging the effects of catecholamines on metabolism.

Safety and Side Effects

Green tea extract is generally safe at recommended dosages, but high doses can cause side effects.

Common Side Effects

At typical doses (250-500mg daily):

• Stomach upset (especially on empty stomach)
• Nausea
• Caffeine-related effects (if not decaffeinated): jitters, insomnia, increased heart rate

Liver Concerns

High doses of green tea extract (typically above 800mg daily) have been associated with liver enzyme elevations in some cases. Most cases involved doses significantly higher than typical supplementation.

To minimize risk:

• Use recommended doses (250-500mg daily)
• Take with food
• Choose quality products from reputable manufacturers
• Avoid combining multiple sources of green tea extract
• Consult a healthcare provider if you have liver conditions

Iron Absorption

Green tea catechins can bind to iron, potentially reducing iron absorption. This is primarily a concern for people with iron deficiency or those at risk.

To minimize this effect:

• Take green tea extract between meals rather than with iron-rich foods
• Separate green tea extract from iron supplements by 2-3 hours
• Monitor iron levels if supplementing long-term

Medication Interactions

Green tea extract may interact with certain medications:

• Blood Thinners: May enhance anticoagulant effects
• Stimulants: Caffeine content may add to stimulant effects
• Blood Pressure Medications: May affect blood pressure
• Chemotherapy Drugs: May interact with certain cancer treatments

Always consult a healthcare provider if taking medications.

Choosing Quality Green Tea Extract

When selecting a green tea extract supplement:

Standardization: Look for products standardized to specific percentages of polyphenols (50-98%) and EGCG (45-50%).

Caffeine Content: Check whether the product contains caffeine or is decaffeinated. Caffeine content should be clearly labeled.

Third-Party Testing: Choose products tested for purity, heavy metals, and contaminants.

Dosage: Ensure the product provides an effective dose (250-500mg extract providing 100-250mg EGCG).

No Unnecessary Additives: Quality products contain minimal fillers or additives.

Reputable Manufacturer: Choose established brands with good manufacturing practices.

Frequently Asked Questions

Explore Our Green Tea Products

Experience the power of green tea extract in our premium formulas:

• MCT Oil Powder - Medium Chain Triglycerides with Green Tea | 30 Servings
• Keto BHB Salts with MCT Oil Green Tea Apple Cider Vinegar - 5-in-1 | 60 Caps
• Max Detox - Acai Berry 500mg with Green Tea Extract | 60 Capsules

Disclaimer: This article is for educational purposes only. The information provided is not intended to diagnose, treat, cure, or prevent any disease. Always consult with a healthcare professional before starting any new supplement regimen.