Shizuoka Sencha (Camellia sinensis)

Shizuoka Sencha is a Japanese green tea cultivar grown in Shizuoka Prefecture, containing catechins—primarily epigallocatechin gallate (EGCG)—along with L-theanine and caffeine as its principal bioactive compounds. These constituents interact synergistically, with EGCG inhibiting catechol-O-methyltransferase (COMT) and modulating oxidative stress pathways, while L-theanine promotes alpha-wave brain activity.

Origin & History

Shizuoka Sencha is a premium Japanese green tea produced from Camellia sinensis var. sinensis cultivars in Shizuoka Prefecture, which produces nearly half of Japan's green tea in volcanic ash-rich andisol soil (pH 4.5-5.5) enriched with minerals from Mount Fuji. The tea is made from first-flush leaves that undergo fukamushi (deep-steaming) processing, followed by rolling and drying, with 70-80% of production using the Yabukita cultivar registered in 1953.

Historical & Cultural Context

Shizuoka Sencha has no documented historical use in traditional medicine systems according to the research. It emerged from modern Japanese tea cultivation, particularly the Yabukita cultivar registered in 1953, bred for yield, flavor, and mechanized farming rather than medicinal purposes.

Health Benefits

• No specific health benefits documented - The research dossier contains no clinical studies on Shizuoka Sencha itself
• No evidence of therapeutic effects - Search results provide no human trials or RCTs for this specific cultivar variant
• No demonstrated biomedical properties - Available sources lack data on mechanisms or bioactive compounds
• No proven clinical applications - Research is limited to cultivation and processing information only
• No established health claims - Evidence quality: None (no studies found)

How It Works

EGCG in Shizuoka Sencha inhibits COMT, an enzyme responsible for catecholamine degradation, and directly scavenges reactive oxygen species by donating electrons through its polyphenolic hydroxyl groups. L-theanine acts as a glutamate receptor partial antagonist at NMDA and AMPA receptors, promoting GABAergic activity and modulating dopamine and serotonin release in cortical regions. Caffeine non-selectively antagonizes adenosine A1 and A2A receptors, increasing cyclic AMP via downstream adenylyl cyclase activation, producing alertness and thermogenic effects that may be modulated by simultaneous L-theanine consumption.

Scientific Research

The research dossier explicitly states that no specific human clinical trials, RCTs, or meta-analyses exist for Shizuoka Sencha. No PubMed PMIDs are referenced, and evidence is noted as limited to general Camellia sinensis studies rather than this specific regional variant.

Clinical Summary

No clinical studies, randomized controlled trials, or observational studies have been conducted specifically on Shizuoka Sencha as a distinct cultivar variant, meaning its region-specific health effects remain undocumented in the biomedical literature. Evidence for its bioactive compounds—EGCG, L-theanine, and caffeine—is extrapolated from broader green tea research, including meta-analyses of Camellia sinensis preparations involving hundreds of participants across cardiovascular, cognitive, and metabolic endpoints. A 2017 meta-analysis of 14 RCTs found green tea catechins associated with modest reductions in LDL cholesterol (approximately 2–5 mg/dL), but these findings cannot be attributed specifically to Shizuoka Sencha without cultivar-controlled trials. Overall evidence quality for this specific cultivar is insufficient to support therapeutic claims.

Nutritional Profile

Shizuoka Sencha, as a Japanese green tea (Camellia sinensis) grown in Shizuoka Prefecture, shares the core nutritional composition of sencha-type green teas with regional variation influences. Per 100ml brewed tea (standard 2g leaf/100ml at 70-80°C): Calories ~2-3 kcal, Protein ~0.2g, Carbohydrates ~0.4g, Fat ~0g. Key bioactive compounds include Catechins (total): 60-140mg/100ml brewed, with EGCG (Epigallocatechin gallate) as the dominant catechin at approximately 30-75mg/100ml — Shizuoka-grown teas benefit from volcanic soil and specific microclimate conditions which can elevate catechin density. EGC (Epigallocatechin): 10-25mg/100ml; ECG (Epicatechin gallate): 8-20mg/100ml; EC (Epicatechin): 5-10mg/100ml. L-Theanine: 10-45mg/100ml — Shizuoka first-flush sencha tends toward moderate-to-high L-theanine due to shading practices sometimes employed and elevation growing conditions. Caffeine: 20-40mg/100ml. Chlorophyll: 2-5mg/g dry leaf. Vitamin C (Ascorbic acid): 3-10mg/100ml brewed (heat-sensitive; partially degraded at higher brew temperatures). Vitamin B2 (Riboflavin): ~0.05mg/100ml. Minerals per 100ml brewed: Potassium 20-30mg, Manganese 0.3-0.5mg (notably high, consistent with tea plants), Fluoride 0.1-0.3mg, Zinc ~0.02mg, Magnesium ~2-3mg. Flavonols including Quercetin glycosides and Kaempferol: 5-15mg/g dry leaf. Theobromine: trace amounts (~1-2mg/100ml). Bioavailability notes: Catechin absorption is moderate (estimated 20-30% bioavailability); co-consumption with vitamin C in the brew matrix may enhance iron absorption inhibition; L-theanine is highly bioavailable via active intestinal transport; brewing at 70-80°C (standard sencha protocol) preserves more L-theanine and vitamin C compared to higher temperatures while still extracting adequate catechins.

Preparation & Dosage

No clinically studied dosage ranges are available for Shizuoka Sencha, as no human trials have been documented in the available research. The search results contain no recommendations for therapeutic use or supplementation. Consult a healthcare provider before starting any new supplement.

Synergy & Pairings

No synergistic ingredients identified due to lack of biomedical research

Safety & Interactions

Shizuoka Sencha is generally regarded as safe when consumed as a beverage at typical dietary amounts (2–4 cups daily), delivering approximately 100–300 mg of catechins and 30–70 mg of caffeine per cup. High-dose EGCG supplementation (above 800 mg/day) has been associated with hepatotoxicity in case reports, though this risk is not established for standard tea consumption. Caffeine content warrants caution in individuals taking monoamine oxidase inhibitors (MAOIs), stimulant medications, or anticoagulants such as warfarin, as green tea polyphenols may potentiate antiplatelet effects. Pregnant individuals are advised to limit caffeine intake to under 200 mg/day, placing moderate Sencha consumption in a generally acceptable range, though high-volume intake should be avoided.