Health – Promoting Effects of Green Tea: A Review
In 1211, a Japanese Zen priest, Yeisai, published a book “Tea and Health Promotion” in which he mentions harvesting tea leaves, production, and pharmacological effects of Tea (Camellia sinensis). On this website we have summarised a significant amount of scientific evidence that green tea is beneficial to health and many of the components of tea have specific health-promoting effects.
In this super review by Yasuo SUZUKI, Noriyuki MIYOSHI and Mamoru ISEMURA (Proc. Jpn. Acad., Ser. B 88, 2012) they discuss the biological activities of Green Tea and its major polyphenolic compounds or catechins which they have studied over a period of 20 years in relation to Health Benefits.
The areas of focus can be summarised thus:
- Anti-metastatic and anti-cancer activities
Data suggest that green tea has an anti-metastatic effect . They found that a green tea infusion was effective at preventing cancer cell metastasis using in vivo and in vitro models.
Metastasis: The transference of a disease to another part of the body, specifically the development of a secondary area of disease remote from the original site, as with some cancers.
- Hepatoprotective effects
Some evidence suggests that Green Tea appears to have Liver protecting properties. The investigators suggest that from a clinical point of view, the application of catechins to therapy for hepatitis C appears to be promising.
- Anti-diabetic effects
Research into the relationship between Green Tea and obesity-related insulin resistance syndrome has shown that Green Tea enhances insulin activity in vitro, and enhances insulin sensitivity in human subjects. Hypertriacylglycerolaemia (high levels of triglycerides) is also reduced in an animal model.
- Anti-obesity and anti-atherosclerotic effects
Evidence has amassed to indicate that the consumption of Green Tea and tea catechins leads to a reduction in body fat as described in recent reviews. The stimulation of fat metabolism might be a factor responsible for the anti-obesity effects of tea catechins. Tea catechins may inhibit cell growth by suppressing lipogenesis in breast cancer cells and stimulation of cell energy expenditure in the mitochondria. Experiments also indicate the suppression of fatty acid synthase gene expression by tea polyphenols. Further, recent results indicated that Green Tea consumption is inversely associated with mortality due to all causes and due to cardiovascular disease.
- Inflammatory Brain Disease and Neuro-protection
Results suggest that Green Tea constituents may open up a new therapeutic avenue for inflammatory brain disease by combining anti-inflammatory and neuroprotective capacities.
Additionally, Theanine and ϒ-aminobutyric acid are also characteristic components of green tea and may promote the release of neurotransmitters
“Modern scientific techniques have given the basis for the health-promoting effects of green tea, which have been recognized from ancient times.
Ingestion of green tea contributes to human health-promotion. Future clinical intervention studies will provide more convincing evidence for effects of green tea.“