What Is Green Tea? Other Names: Benifuuki, Camellia sinensis, Epigallo Catechin Gallate
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What is Green Tea?
This post was written with Consensus AI Academic Search Engine – please read our Disclaimer at the end of this article. Green tea, derived from the leaves of the Camellia sinensis plant, is a widely consumed beverage known for its potential health benefits. Unlike black tea, green tea is minimally processed, which helps retain its natural polyphenols, particularly catechins, which are believed to contribute to its health-promoting properties. Other names include: Benifuuki, Camellia sinensis, Camellia thea, Camellia theifera, Constituant Polyphénolique de Thé Vert, CPTV, EGCG, Epigallo Catechin Gallate, Épigallo-Catéchine Gallate, Epigallocatechin Gallate, Extrait de Camellia Sinensis, Extrait de Thé, Extrait de Thé Vert, Extrait de Thea Sinensis, Green Sencha Tea, Green Tea Extract, Green Tea Polyphenolic Fraction, GTP, GTPF, Japanese Sencha Green Tea, Japanese Tea, Kunecatechins, Matcha Green Tea, Poly E, Polyphenon E, PTV, Té Verde, Tea, Tea Extract, Tea Green, Thé, Thé de Camillia, Thé Japonais, Thé Vert, Thé Vert de Yame, Thé Vert Sensha, Thea bohea, Thea sinensis, Thea viridis, Yame Green Tea, Yabukita, Yame Tea.
Health Benefits of Green Tea
Cardiovascular Health
Green tea has been shown to exert cardioprotective benefits. For instance, a study found that daily consumption of green tea significantly reduced plasma serum amyloid alpha, an independent cardiovascular disease risk factor, in obese subjects with metabolic syndrome1. Additionally, green tea consumption has been associated with reversing endothelial dysfunction in healthy smokers, which is a critical factor in the development of atherosclerosis4.
Weight Management and Metabolic Effects
Green tea is also noted for its role in weight management and metabolic health. A clinical trial demonstrated that green tea extract could increase 24-hour energy expenditure and fat oxidation in humans, suggesting its potential in body composition control via sympathetic activation of thermogenesis and fat oxidation2. Another study highlighted that high-dose green tea extract led to significant weight loss, reduced waist circumference, and improved lipid profiles in women with central obesity8.
Antioxidant Properties
The antioxidant properties of green tea are well-documented. Green tea polyphenols have been shown to increase plasma antioxidant capacity and whole blood glutathione levels in adults with metabolic syndrome, providing antioxidant protection6. Moreover, green tea polyphenols have been found to protect the skin against harmful UV radiation and improve overall skin quality in women7.
Reproductive Health
Green tea may also have beneficial effects on reproductive health. Research on male rats indicated that green tea consumption increased sperm concentration and viability without adverse effects on reproductive, liver, and kidney health3.
Insulin Sensitivity and Glucose Tolerance
Green tea has been shown to improve insulin sensitivity and glucose tolerance. In a study involving Sprague-Dawley rats, green tea supplementation resulted in lower fasting plasma levels of glucose, insulin, triglycerides, and free fatty acids, along with increased insulin-stimulated glucose uptake5. Similarly, acute ingestion of green tea extract improved insulin sensitivity and glucose tolerance in healthy young men10.
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Adverse Effects of Green Tea
Gastrointestinal Issues
Consumption of green tea polyphenols can cause mild gastrointestinal issues such as excess gas, upset stomach, nausea, heartburn, stomach ache, and abdominal pain1.
Liver Toxicity
High doses of green tea extract (GTE) have been linked to liver enzyme elevations, indicating potential liver injury. This includes significant increases in alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels3.
Therapeutic doses of GTE can provoke liver damage and exacerbate paracetamol-induced hepatotoxicity through oxidative stress and caspase 3-dependent apoptosis10.
Hematological Effects
In Wistar rats, high doses of green tea extract led to a significant decrease in white blood cell (WBC) count and platelet count, suggesting potential hematological toxicity at higher doses2.
Developmental Toxicity
Prenatal exposure to high doses of green tea extract in rats resulted in significant decreases in body weight of both mothers and fetuses, along with various signs of neuronal tissue degeneration in the cerebral cortex, cerebellum, and spinal cord4.
Neurological Effects
High doses of green tea extract during pregnancy caused histological, immunohistochemical, and ultrastructural degenerative changes in the central nervous system of rat fetuses4.
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How has Green Tea Improved Patient Outcomes?
Reduction in Disease Activity and Improved Quality of Life in Autoimmune Diseases
Green tea extract significantly reduced disease activity and improved vitality and general health in patients with systemic lupus erythematosus1.
Cardiovascular and Metabolic Health Improvements
Green tea extract significantly lowered blood pressure, fasting glucose, insulin levels, and insulin resistance in obese, hypertensive patients. It also improved lipid profiles by reducing total and LDL cholesterol and increasing HDL cholesterol2 3.
Enhanced Insulin Sensitivity and Lipid Profiles in Diabetes
Green tea extract significantly improved insulin resistance and increased HDL cholesterol in patients with type 2 diabetes and lipid abnormalities3. It also reduced HbA1c levels and improved lipid profiles in patients with diabetic nephropathy6.
Improved Outcomes in Acute Ischemic Stroke
Green tea extract improved clinical outcomes in acute ischemic stroke patients by reducing inflammation and oxidative stress markers4.
Oral Health in Cancer Patients
Green tea mouthwash significantly improved oral health status in oral cancer patients undergoing treatment, reducing oral mucositis and maintaining better oral hygiene5.
Liver Function and Fat Reduction in NAFLD
High-density catechin green tea significantly improved liver function and reduced body fat and oxidative stress in patients with non-alcoholic fatty liver disease (NAFLD)7.
Pain and Physical Function in Osteoarthritis
Green tea extract, when used as an adjunctive treatment, significantly reduced pain and improved physical function in patients with knee osteoarthritis8.
Endothelial Function in Chronic Kidney Disease
Short-term green tea consumption improved flow-mediated endothelium-dependent vasodilation in patients with chronic kidney disease, although it did not affect circulating endothelial progenitor cells9.
Peripheral Neuropathy in Diabetes
Green tea extract intake significantly reduced pain and improved clinical and neurophysiological parameters in patients with mild-to-moderate diabetic peripheral neuropathy10.
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Green Tea Mechanisms of Action
Antioxidant and Anti-inflammatory Effects
Green tea increases antioxidant enzyme activity and reduces oxidative stress markers, such as lipid hydroperoxide and malondialdehyde (MDA), in various tissues, including the heart and liver2 3 10.
It enhances the expression of antioxidant proteins like heme oxygenase-1 and Nrf-2, contributing to its protective effects against oxidative damage3 5.
Metabolic Regulation
Green tea improves insulin sensitivity and glucose metabolism by increasing the expression of glucose transporters (GLUT IV) and enhancing insulin-stimulated glucose uptake in adipocytes6 7 8.
It modulates lipid metabolism, reducing serum lipids and promoting fatty acid oxidation, which helps in managing metabolic disorders3 8.
Cardioprotective Effects
Green tea attenuates cardiac remodeling and improves cardiac function by reducing oxidative stress, enhancing antioxidant defenses, and modulating extracellular matrix components2 3.
It also decreases markers of cardiac hypertrophy and improves systolic and diastolic function in models of myocardial infarction3.
Genoprotective Effects
Regular intake of green tea reduces DNA damage and enhances DNA repair mechanisms, possibly through redox-sensitive cytoprotective adaptations and increased activity of DNA repair enzymes like human oxoguanine glycosylase 1 (hOGG1)5.
Adrenergic and Energy Metabolism
Contrary to some hypotheses, green tea does not significantly enhance adrenergic stimulation (adrenaline and noradrenaline) but affects metabolites related to fat metabolism and the tricarboxylic acid (TCA) cycle1.
Reproductive Health
Green tea improves sperm concentration and viability without causing significant adverse effects on reproductive, liver, or kidney health, although some subtle structural changes in reproductive tissues warrant further investigation4.
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Common Complaints Associated with Green Tea Use
Interference with Sleep: Caffeine in green tea can interfere with sleep quality. Lowering the caffeine content in green tea (low-caffeine green tea, LCGT) has been shown to improve sleep quality in middle-aged individuals1.
Increased Stress: Standard green tea (SGT) with higher caffeine content can increase stress levels, as indicated by higher salivary α-amylase activity, a stress marker. In contrast, LCGT reduces stress more effectively1.
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Disclaimer
The content presented in this blog is generated by Consensus, an AI-powered academic search engine, and is based on publicly available scientific literature. While every effort is made to provide accurate, up-to-date, and well-researched information, the content is intended for informational and educational purposes only. It does not constitute medical advice, diagnosis, or treatment. Always consult a qualified healthcare professional before making any decisions regarding medical conditions, treatments, or medications. The AI system’s analysis may not cover all perspectives, emerging research, or individual cases, and it is not a substitute for professional expertise. Neither the blog publisher nor the developers of the AI-powered search engine are responsible for any actions taken based on the information provided in this content. Use of this information is at your own risk. Citations to the original scientific studies are included for reference, but these studies should be reviewed in full and interpreted with the guidance of a healthcare or research professional.
If you are experiencing a medical emergency, please seek immediate attention from a healthcare provider.
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