Untitled Document Green Tea is one of the most extensively, and successfully, researched herbs in the world today. It was first noticed several decades ago, that people involved in presenting the green tea ceremonies had remarkably low incidence of cancer. Hundreds of studies later, we now know that green tea, and in fact all tea (Camellia sinensis) as a wide range of beneficial properties for reducing risks of cancer, heart disease and liver disease, plus antioxidant properties, benefits for the skin and much more. Here is some of the recent research on tea and its antioxidant polyphenols.

Green Tea Consumption And Liver Disease

February 24, 2009 by  
Filed under All, Science, Tea

Just to keep things in perspective, the previous item about green
tea extracts potentially causing liver problems must be balanced
against research showing that green tea is protective against liver
disease. Chinese researchers a value weighted interventional and
observational studies in both Western countries and in China published
between 1989 and 2007. They found “a significant protective role
of green tea against various liver diseases” and “a
positive correlation between green tea intake and attenuation of liver
disease.” Their conclusion? “An increased consumption of
green tea may reduce the risk of liver disease.”

Green tea consumption and liver disease: a systematic review. Liver Int. 2008 May 14. [Epub ahead of print]
Jin X, Zheng RH, Li YM.

Objectives: To present the effect of green tea consumption against
liver disease. Data sources: Interventional and observational studies
both in Western countries and in China and published between the years
1989 and December 2007. Review Methods: The articles were retrieved
from Medline, Embase database, Chinese biomedicine web database and
Chinese scientific journal’s database using proper MESH headings
and assessed by two independent investigators according to established
inclusion criteria. The characteristics and outcomes of the chosen
articles were displayed for further analysis and the quality of each
study was also evaluated according to the widely acknowledged criteria.
P<0.05 was defined as statistically significant in all enrolled
trials. Results: Ten qualified studies (eight from China, one from
Japan and the other from the USA) with various outcomes such as liver
cancer, cirrhosis and fatty liver disease were finally chosen. Among
them, study designs differed in that there were four
randomized-controlled clinical trials, two cohort, one case-control and
three cross-sectional studies. The heterogeneity in the study design,
outcomes, cofounders and amount of tea consumption precluded further
meta-analysis. Nevertheless, eight studies showed a significant
protective role of green tea against various liver diseases as
determined by relative risk/odds ratio or P-value and among them, four
studies showed a positive correlation between green tea intake and
attenuation of liver disease. Moreover, the other two studies also
presented the protective tendency of green tea against liver disease.
Conclusions: An increased consumption of green tea may reduce the risk
of liver disease.

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Tea And Sweat: A New Antiaging Strategy

February 24, 2009 by  
Filed under All, Science, Tea

Japanese researchers explored the effect of tea catechins and
regular exercise and the aging associated declining physical
performance in mice. The endurance capacity of mice as measured by
running time decreased by 17% in control mice, while those fed green
tea catechins (0.35%) suffered no decline in endurance. The authors
concluded “long-term intake of catechins, together with habitual
exercise, is beneficial for suppressing the age-related decline in
physical performance and energy metabolism, and these effects are due,
at least in part, to improved mitochondrial function in skeletal
muscle.”

Tea catechin ingestion combined with habitual exercise suppresses
the aging-associated decline in physical performance in
senescence-accelerated mice.

Am J Physiol Regul Integr Comp Physiol. 2008 May 14. Murase T, Haramizu S, Ota N, Hase T.

Catechins, which are abundant in green tea, possess a variety of
biologic actions, and their clinical application has been extensively
investigated. In this study, we examined the effects of tea catechins
and regular exercise on the aging-associated decline in physical
performance in senescence-accelerated prone mice (SAMP1) and
age-matched senescence-accelerated resistant mice (SAMR1). The
endurance capacity of SAMR1 mice, measured as the running time to
exhaustion, tended to increase over the 8-week experimental period,
whereas that of SAMP1 mice decreased by 17%. On the other hand, the
endurance capacity of SAMP1 mice fed 0.35% (w/w) catechins remained at
the initial level and was significantly higher than that of SAMP1 mice
not fed catechins. In SAMP1 mice fed catechins and given exercise,
oxygen consumption was significantly increased, and there was an
increase in skeletal muscle fatty acid beta-oxidation. The mRNA levels
of mitochondria-related molecules, such as peroxisome
proliferator-activated receptor-gamma coactivator-1, cytochrome c
oxidase-II, III, and IV in skeletal muscle were also higher in SAMP1
mice given both catechins and exercise. Moreover, oxidative stress
measured as thiobarbituric reactive substances was lower in SAMP1
groups fed catechins than in the SAMP1 control group. These results
suggest that long-term intake of catechins, together with habitual
exercise, is beneficial for suppressing the aging-related decline in
physical performance and energy metabolism, and that these effects are
due, at least in part, to improved mitochondrial function in skeletal
muscle. Key words: energy metabolism, exercise, green tea,
mitochondria, oxidative stress.

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Effect Of Green Tea Extract On Obese Women

February 24, 2009 by  
Filed under All, Science, Tea

Scientists in Taiwan studied the effect of green tea extract on 78
obese women aged 16 to 60 years. They found no significant improvement
in body weight, body mass index and weight circumflex. There were
significant improvements in LDL cholesterol and triglyceride.

Effect of green tea extract on obese women: A randomized, double-blind, placebo-controlled clinical trial.

Clin Nutr. 2008 May 9. [Epub ahead of print]. Hsu CH, Tsai TH, Kao YH, Hwang KC, Tseng TY, Chou P.

AIMS: To examine the effect of green tea extract (GTE) on obese
women and to explore the relationship between GTE and obesity-related
hormone peptides. METHODS: A randomized, double-blind,
placebo-controlled clinical trial was conducted from July 2006 to June
2007 in Taipei Hospital, Taiwan. Seventy-eight of 100 obese women aged
between 16 and 60years with BMI>27kg/m(2) and who had not received
any other weight control maneuvers within the last 3months completed
this study. The subjects were randomly divided into Groups A and B.
Group A (n=41) received GTE while Group B (n=37) took cellulose as a
placebo, one capsule (400mg) three times each day for 12weeks. The body
weight (BW), body mass index (BMI) and waist circumflex (WC) were
measured at the beginning of the study and after 12weeks of treatment
with GTE. The data were compared and expressed as % reduction. RESULTS:
There was only a 0.3% reduction in BW (0.15kg) after 12weeks of
treatment with GTE. There was no statistical difference in % reduction
in BW, BMI and WC between the GTE and placebo groups. Within group
comparison revealed that the GTE group had significant reduction in
LDL-cholesterol and triglyceride, and marked increase in the level of
HDL-cholesterol, adiponectin and ghrelin. On the other hand, the
placebo group showed significant reduction in triglyceride only, and a
marked increase in the level of ghrelin alone. CONCLUSIONS: This study
showed no statistical difference in % reduction in BW, BMI and WC
between the GTE and placebo groups after 12weeks of treatment. The
intake of GTE (491mg catechins containing 302mg EGCG) for 12weeks is
considered safe as shown by the results.

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Green Tea for Keloids

February 24, 2009 by  
Filed under All, Science, Tea

New research from Korea shows that EGCG selectively suppressed
keloid fibroblast proliferation and migration compared to its effect on
normal fibroblast proliferation and migration. Keloids are common
benign skin tumors, characterized by collagen accumulation and
hyperproliferation of fibroblasts.

Green Tea Polyphenol Epigallocatechin-3-Gallate Suppresses Collagen
Production and Proliferation in Keloid Fibroblasts via Inhibition of
the STAT3-Signaling Pathway.

J Invest Dermatol. 2008 May 8. Park G, Yoon BS, Moon JH, Kim B, Jun EK, Oh S, Kim H, Song HJ, Noh JY, Oh C, You S.

Keloids are benign skin tumors characterized by collagen
accumulation and hyperproliferation of fibroblasts. To find an
effective therapy for keloids, we explored the pharmacological
potential of (-)-epigallocatechin-3-gallate (EGCG), a widely
investigated tumor-preventive agent. When applied to normal and keloid
fibroblasts (KFs) in vitro, proliferation and migration of KFs were
more strongly suppressed by EGCG than normal fibroblast proliferation
and migration (IC(50): 54.4 muM (keloid fibroblast (KF)) versus 63.0
muM (NF)). The level of Smad2/3, signal transducer and activator of
transcription-3 (STAT3), and p38 phosphorylation is more enhanced in
KFs, and EGCG inhibited phosphorylation of
phosphatidylinositol-3-kinase (PI3K), extracellular signal-regulated
protein kinase 1/2 (ERK1/2), and STAT3 (Tyr705 and Ser727). To evaluate
the contribution of these pathways to keloid pathology, we treated KFs
with specific inhibitors for PI3K, ERK1/2, or STAT3. Although a PI3K
inhibitor significantly suppressed proliferation, PI3K and MEK/ERK
inhibitors had a minor effect on migration and collagen production.
However, a JAK2/STAT3 inhibitor and a STAT3 siRNA strongly suppressed
proliferation, migration, and collagen production by KFs. We also found
that treatment with EGCG suppressed growth and collagen production in
the in vivo keloid model. This study demonstrates that EGCG suppresses
the pathological characteristics of keloids through inhibition of the
STAT3-signaling pathway. We propose that EGCG has potential in the
treatment and prevention of keloids.Journal of Investigative
Dermatology advance online publication, 8 May 2008;
doi:10.1038/jid.2008.103.

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Green Tea for Keloids

May 28, 2008 by  
Filed under All, Science, Tea

New research from Korea shows that EGCG selectively suppressed keloid fibroblast proliferation and migration compared to its effect on normal fibroblast proliferation and migration. Keloids are common benign skin tumors, characterized by collagen accumulation and hyperproliferation of fibroblasts. Read more

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Green Tea Polyphenols Protect The Skin

May 28, 2008 by  
Filed under All, Science, Tea

Green tea polyphenols have been reported to preserve tissues such as blood vessels, corneas, nerves, islet cells, articular cartilage, and myocardium. Research in Japan examined the effects of EGCG on skin preservation. Utilizing epidermal and dermal skin cells in culture, the researchers report that the tea polyphenol helped to preserve the skin cells for up to seven weeks and allowed successful skin grafting. The researchers commented that these findings suggest “the future clinical usefulness of EGCG for skin preservation, however the mechanism by which EGCG promotes skin preservation still remains unclear.” Read more

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Effect Of Green Tea Extract On Obese Women

May 28, 2008 by  
Filed under All, Science, Tea

Scientists in Taiwan studied the effect of green tea extract on 78 obese women aged 16 to 60 years. They found no significant improvement in body weight, body mass index and weight circumflex. There were significant improvements in LDL cholesterol and triglyceride. Read more

Tags:

Tea And Sweat: A New Antiaging Strategy

May 28, 2008 by  
Filed under All, Science, Tea

Japanese researchers explored the effect of tea catechins and regular exercise and the aging associated declining physical performance in mice. The endurance capacity of mice as measured by running time decreased by 17% in control mice, while those fed green tea catechins (0.35%) suffered no decline in endurance. The authors concluded “long-term intake of catechins, together with habitual exercise, is beneficial for suppressing the age-related decline in physical performance and energy metabolism, and these effects are due, at least in part, to improved mitochondrial function in skeletal muscle.” Read more

Tags:

Green Tea Consumption And Liver Disease

May 28, 2008 by  
Filed under All, Science, Tea

Just to keep things in perspective, the previous item about green tea extracts potentially causing liver problems must be balanced against research showing that green tea is protective against liver disease. Chinese researchers a value weighted interventional and observational studies in both Western countries and in China published between 1989 and 2007. They found “a significant protective role of green tea against various liver diseases” and “a positive correlation between green tea intake and attenuation of liver disease.” Their conclusion? “An increased consumption of green tea may reduce the risk of liver disease.” Read more

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USP Investigates Safety Of Green Tea Extracts

May 28, 2008 by  
Filed under All, Politics, Science, Tea

Green tea is the fourth most commonly used dietary supplement in the United States. After the publication of adverse event case reports involving green tea products and potential liver toxicity, the US Pharmacopeia reviewed safety information for green tea products. 216 case reports on green tea products were analyzed including 34 reports concerning liver damage. 27 reports pertaining to liver damage were categorized as possible causality and seven as probable causality. Pharmacokinetic and animal toxicological studies indicate that consumption of green tea concentrated extracts on an empty stomach is more likely to lead to adverse effects than consumption in the fed state. USP concluded “when dietary supplement products containing green tea extracts are used in formulated appropriately the Committee is unaware of significant safety issues that would prohibit monograph development, provided that caution statement is included in the labeling section.” Read more

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