Green Tea

Overview

Green tea provides catechins (especially EGCG), L-theanine, and polyphenols that support cognitive function, antioxidant defenses, and metabolic health. Green tea contributes manganese and small amounts of fluoride and potassium, alongside polyphenols that support antioxidant defenses. Green tea catechins (e.g., EGCG, EGC) contribute to visceral adipose tissue reduction and neuroprotective effects in Green Mediterranean Diet studies, which showed attenuated brain atrophy by ~50%. Green tea is also mentioned as a polyphenol antimicrobial for SIBO suppression.

Food Context

Synergies

• Can reduce non-heme iron absorption if taken with meals; space ≥1 hour from iron-rich meals or add lemon (vitamin C) to mitigate this

Preparation

• Steep at lower temperatures to preserve catechins and prevent degradation
• Green tea catechins increase Faecalibacterium and Roseburia; inhibit Enterobacteriaceae; reduce NF-κB activation
• L-theanine found in green tea increases alpha waves and calms without sedation

Recipes

1 recipe containing this food

Matcha Mitochondria Smoothie

Mitochondrial energising smoothie rich in polyphenols, magnesium, and antioxidants

Nutrient Tables (per 100 g)

Core nutrients

Nutrient	Amount per 100 g	% RDA per 100 g
Energy	0 kcal	—
Protein	0 g	—
Total fat	0 g	—
Carbohydrates	0 g	—

Bioactive compounds

Values below are often from specialist compositional databases or literature, not the standard USDA panel. Asterisks (*) refer to source notes at the bottom of this section.

Compound / class	Amount per 100 g	Notes
EGCG	30 mg *	Dominant catechin in many green teas; very sensitive to leaf dose, time, and temperature.
L-Theanine	6 mg *	Tea-specific amino acid; often co-discussed with catechins for calm focus.

Note: Bioactive-compound values vary substantially by cultivar, species, cocoa or oil percentage, processing, and brand formulation. Show quantitative values only where a defensible source exists; otherwise prefer qualitative presence statements or ranges in source notes.

Source notes (bioactive / supplementary):

• * EGCG: Order-of-magnitude for a typical brewed green tea beverage scaled to per 100 g liquid; cup strength and cultivar dominate variance (USDA brew panels are not a full polyphenol spec).
• * L-Theanine: Approximate per 100 g brewed beverage; shade-grown teas can be higher.

Functional metrics

Metric	Score	Notes
Total catechins (brewed proxy)	Varies by product	Pool includes EGCG, EGC, ECG, and EC; brewing dominates extraction.

Note: Functional-metric values depend strongly on assay method, processing, and product formulation. Use these as contextual metrics, not strict like-for-like nutrient equivalents.

Reference intakes: US Dietary Reference Intakes for adults (19–50 years; using the higher of male/female values where they differ).

Data provenance (core / micronutrient panel): USDA FoodData Central, GREEN TEA, FDC ID 2048695, API, per 100 g edible portion, last checked 2026-03-14

Substances

Substances in this food: editorial (Overview / literature) plus analytical (nutrition table).

4 substances in this food

EGCG (Green Tea Catechin)

Polyphenol; antioxidant; gut barrier/LPS modulation; supports microbiome

L-Theanine

Calming amino acid from tea; increases alpha waves; sleep-friendly

Manganese

Cofactor for MnSOD (SOD2); mitochondrial antioxidant defense

Potassium

Electrolyte for nerve transmission, muscle function, and blood pressure regulation

References

• Green tea contributes manganese and small amounts of fluoride and potassium, alongside polyphenols that support antioxidant defenses
• Green tea catechins (e.g., EGCG, EGC) contribute to visceral adipose tissue reduction and neuroprotective effects in Green Mediterranean Diet studies Zelicha et al. 2022
• Green Mediterranean Diet attenuated brain atrophy by ~50%, with glycemic control contributing to the neuroprotective signal, consistent with polyphenol–fibre–microbiome synergy Pachter et al. 2024
• Polyphenol antimicrobials (berberine, oregano, green tea) for SIBO suppression
• Exercise-induced BDNF surges can be potentiated by polyphenols (e.g., blueberries, green tea)
• Polyphenol sources including green tea catechins increase Faecalibacterium and Roseburia; inhibit Enterobacteriaceae; reduce NF-κB activation
• GABA: Main inhibitory neurotransmitter; food sources include green tea, fermented foods, polyphenols (genistein), spinach, almonds, pumpkin seeds