Grenx

Green Tea Consumption and Mortality Due to Cardiovascular Disease, Cancer, and All Causes in Japan – The Ohsaki Study.  JAMA, September 13, 2006—Vol 296, No. 10 

Objective To investigate the associations between green tea consumption and allcause and cause-specific mortality.  

Design, Setting, and Participants The Ohsaki National Health Insurance Cohort Study, a population-based, prospective cohort study initiated in 1994 among 40 530 Japanese adults aged 40 to 79 years without history of stroke, coronary heart disease, or cancer at baseline. Participants were followed up for up to 11 years (1995-2005) for all-cause mortality and for up to 7 years (1995-2001) for cause-specific mortality.  

Results Over 11 years of follow-up (follow-up rate, 86.1%) the inverse association with all-cause mortality was stronger in women (P=.03 for interaction with sex). In men, the multivariate hazard ratios of mortality due to all causes associated with different green tea consumption frequencies.  The inverse association with cardiovascular disease mortality was stronger than that with all-cause mortality. This inverse association was also stronger in women (P=.08 for interaction with sex). In women, the multivariate hazard ratios of cardiovascular disease mortality across increasing green tea consumption categories were 1.00, 0.84 (95% CI, 0.63-1.12), 0.69 (95% CI, 0.52-0.93), and 0.69 (95% CI, 0.53-0.90), respectively (P=.004 for trend). Among the types of cardiovascular disease mortality, the strongest inverse association was observed for stroke mortality. In contrast, the hazard ratios of cancer mortality were not significantly different from 1.00 in all green tea categories compared with the lowest-consumption category.

 Conclusion Green tea consumption is associated with reduced mortality due to all causes and due to cardiovascular disease but not with reduced mortality due to cancer. 

“This particular study followed over 40,000 people for 11 years.  Just the sheer size of this study is impressive in and of itself.  What really impressed me was the inverse relationship between the cups of tea and the decrease in cause-specific deaths.  Those who consumed the right amount of green tea antioxidants had the most significant decrease in risk factors.” – Josh Smith

Basu A.  Green tea supplementation affects body weight, lipids, and lipid peroxidation in obese subjects with metabolic syndrome.  J Am Coll Nutr. 2010 Feb;29(1):31-40. 

With an alarming rise in the prevalence of obesity and metabolic syndrome (MeS) in the U.S. population, use of alternative nutrition therapies, such as dietary supplements, to promote weight loss has been increasing. MeS, a constellation of risk factors, including atherogenic dyslipidemia (low high-density lipoprotein [HDL], high triglyceride), impaired fasting glucose, hypertension, and central adiposity, also predisposes to higher risks of oxidative stress, type 2 Diabetes and atherosclerotic cardiovascular disease. Diet and exercise have been shown to improve oxidative stress, insulin sensitivity, and atherosclerotic risk factors in subjects with MeS. Selected clinical trials in overweight and obese subjects have shown green tea catechins to reduce body fat and body weight or to maintain weight loss when catechin doses in the range of 270–750 mg are used, although the effects of green tea supplementation in the U.S. population with metabolic syndrome have not been reported. 

“This is a great randomized controlled trial with single-blinded design.  One point of interest was the use of 270-750mg of catechins.  Catechins are the antioxidants from green tea leaves, of which EGCG is the most potent and biologically active.  EGCG was shown, in this study, to help reduce visceral body fat which helps reduce the risk of the metabolic syndrome.  Get the right amount of EGCGs and reap the benefits.” – Josh Smith

Effects of Catechin Enriched Green Tea on Body Composition.  Wang et al. Obesity (2010) 18, 773–779.  Obesity is a major health problem in the developed and developing world. Many “functional” foods and ingredients are advocated for their effects on body composition but few have consistent scientific support for their efficacy.  However, an increasing amount of mechanistic and clinical evidence is building for green tea (GT). This experiment was therefore undertaken to study the effects of a high-catechin GT on body composition in a moderately overweight Chinese population. In a randomized placebo-controlled trial, 182 moderately overweight Chinese subjects, consumed either two servings of a control drink (C; 30 mg catechins, 10 mg caffeine/day), one serving of the control drink and one serving of an extra high-catechin GT1 (458 mg catechins, 104 mg caffeine/day), two servings of a high-catechin GT2 (468 mg catechins, 126 mg caffeine/day) or two servings of the extra high-catechin GT3 (886 mg catechins, 198 mg caffeine/day) for 90 days. Data were collected at 0, 30, 60, and 90 days. We observed a decrease in estimated intra-abdominal fat (IAF) area of 5.6 cm2 in the GT3 group. In addition, we found decreases of 1.9 cm in waist circumference and 1.2 kg body weight in the GT3 group vs. C (P < 0.05). We also observed reductions in total body fat (GT2, 0.7 kg, P < 0.05) and body fat % (GT1, 0.6%, P < 0.05). We conclude that consumption of two servings of an extra high catechins GT leads to improvements in body composition and reduces abdominal fatness in moderately overweight Chinese subjects.

“This randomized placebo-controlled trial was a solid examination of the quantity of EGCG and body composition.  This article examined the amount of EGCG needed to reduce visceral body fat as well as waist circumference.  Waist circumference is often used as a quick measure of obesity, which makes it a great reference point for measuring progress with the different combinations of green tea catechins.  The conclusion is that the beverages enhanced with catechins reduced body fat percentage as well as taking inches off the waist.  Consuming 450mg to 850mg of green tea catechins produced these results.” – Josh Smith

M.S. Westerterp-Plantenga / International Journal of Obesity (2010) 34, 659–669.  The global prevalence of obesity has increased considerably in the last decade. Tools for obesity management including caffeine, and green tea have been proposed as strategies for weight loss and weight maintenance.  These ingredients may increase energy expenditure and have been proposed to counteract the decrease in metabolic rate that is present during weight loss. Positive effects on body-weight management have been shown using green tea mixtures. A green tea–caffeine mixture improves weight maintenance, through thermogenesis, fat oxidation, and sparing fat free mass. The sympathetic nervous system is involved in the regulation of lipolysis, and the sympathetic innervation of white adipose tissue may play an important role in the regulation of total body fat in general.  Taken together, these functional ingredients have the potential to produce significant effects on metabolic targets such as thermogenesis, and fat oxidation.

“This review article compiles research from the last 15 to 20 years.  Within the last several years there has been a greater understanding of how green tea extract works.  Not only does drinking the antioxidants from green tea help on the cellular level to improve fat oxidation, but it can replace high calorie, sugar loaded beverages.” – Josh Smith

Agricultural and Biological Chemistry.  1989.  Volume 53, No. 9 pp. 2307-2311 – An extract of Japanese green tea, one of the most popular drinks in Japan, was an inhibitor of the growth of Streptococcus mutans, a bacterium responsible for causing dental caries. The analysis of the extract revealed that the main antibacterial components of the extract were several polv phenolic compounds, especially gallocatechin (GC), epigallocatechin (EGC), and epigallocatechin gallate (EGCg). GC was the most active component and its minimum inhibitory concentration against the bacterium was around 250 μg per ml.

“Traiditionally in Japan individuals drink green tea after a meal.  This is said to have a cleansing effect on the teeth and mouth.  This research article shows how green tea does in fact help in the prevention of cavaties.  The most popular antioxidant from green tea, EGCG, usually gets all the attention, but in this case GC (gallocatechin) deserves the majority of the credit.  GC inhibits the growth of a certain bacteria that causes dental cavaties.” – Josh Smith

Can green tea do that? A literature review of the clinical evidence.  Preventive Medicine 49 (2009) 83–87 

Objective. Habitual green tea consumption has long been associated with health benefits including chemoprevention and cardiovascular protection. This non-systematic literature review presents the clinical evidence to date. Method. A literature review of peer-reviewed articles on observational and interventional studies was conducted to include green tea, its extract or its purified polyphenol (−)-epigallocatechin-3-gallate (EGCG). Electronic databases searched included PubMed (1966–2009) and the Cochrane Library (Issue 4, 2008). Results: observational studies are inconclusive on the benefits of habitual consumption of green tea in the prevention of most cancers. However, there are trends towards prevention in breast and prostate cancers. Interventional studies have demonstrated reduction in relapses following surgical resection in colorectal adenomas and increased survival rates in epithelial ovarian cancer. Observational studies indicate that green tea may provide protection against hypertension and reduce the risk for stroke, and interventional studies are providing biochemical and physiological evidence. Conclusion. Although the overall clinical evidence is inconclusive, habitual green tea consumption may be providing some level of chemoprevention in prostate and breast cancer. Green tea may also attenuate the risk factors association with the development of atherosclerosis thus reducing the incidence of cardiovascular events and stoke.

“Taking a look at the clinical trials that have been conducted on green tea so far with such technical topics as cancer, hypertension and atherosclerosis, there are great emerging results of daily consumption of green tea.  400 milligrams of EGCG is the amount of antioxidants from green tea that have been identified as the “right amount”.  – Josh Smith 

Objectives To investigate the association between green tea consumption and liver cancer incidence. Methods: We prospectively followed 41,761 Japanese adults aged 40–79 years, without a history of cancer at the baseline or any missing data for green tea consumption frequency. Cox proportional hazards models were used to calculate hazard ratios (HR) with 95% confidence intervals (CI), adjusted for age, alcohol drinking, smoking, the consumption of coffee, vegetables, dairy products, fruit, fish, and soybean. Results Over 9 years of follow-up, among 325,947 accrued person-years, the total incidence of liver cancer was 247 cases. We found that green tea consumption was inversely associated with the incidence of liver cancer. In men, the multivariate-adjusted HRs (95% CIs) for liver cancer incidence with different green tea consumption categories were 1.00 (reference) for\1 cup/day, 0.83 (0.53–1.30) for 1–2 cups/day, 1.11 (0.73–1.68) for 3–4 cups/day, and 0.63 (0.41–0.98) for C5 cups/day (p for trend = 0.11). The corresponding data among women were 1.00 (reference), 0.68 (0.35–1.31), 0.79 (0.44–1.44), 0.50 (0.27–0.90) (p for trend = 0.04). Conclusions Green tea consumption is associated with a reduced risk of liver cancer incidence.

“Following over 40,000 individuals for 9 years has shown a strong association between decreasing the risk of liver cancer and drinking green tea.  Liver cancer is the 6th most common cancer and drinking 5 or more cups of fresh green tea per day significantly decreases the risk of liver cancer.” – Josh Smith

Body Weight Loss and Weight Maintenance in Relation to Habitual Caffeine Intake and Green Tea Supplementation.  Obesity Research (2005) ;13:1195–1204. 

Objective: Investigation of the effect of a green tea-caffeine mixture on weight maintenance after body weight loss in moderately obese subjects in relation to habitual caffeine intake.

Research Methods and Procedures: A randomized placebo-controlled double blind parallel trial in 76 overweight and moderately obese subjects, (BMI, 27.5 ± 2.7 kg/m2) Matched for sex, age, BMI, height, body mass, and habitual caffeine intake was conducted. A very low energy diet intervention during 4 weeks was followed by 3 months of weight maintenance (WM); during the WM period, the subjects received a green tea-caffeine mixture (270 mg epigallocatechin gallate; 150 mg caffeine per day) or placebo.

Results: Subjects lost 5.9 ±1.8 (SD) kg (7.0 ± 2.1%) of body weight (p ≥ 0.001). At baseline, satiety was positively, and in women, leptin was inversely, related to subjects’ habitual caffeine consumption (p ≥ 0.01). High caffeine consumers reduced weight, fat mass, and waist circumference more than low caffeine consumers; resting energy expenditure was reduced less and respiratory quotient was reduced more during weight loss (p ≥ 0.01). In the low caffeine consumers, during WM, green tea still reduced body weight, waist, respiratory quotient and body fat, whereas resting energy expenditure was increased compared with a restoration of these variables with placebo (p 0.01). In the high caffeine consumers, no effects of the green tea-caffeine mixture were observed during WM.

Discussion: High caffeine intake was associated with weight loss through thermogenesis and fat oxidation and with suppressed leptin in women. In habitual low caffeine consumers, the green tea-caffeine mixture improved WM, partly through thermogenesis and fat oxidation.

“This was a great article to provide more understanding about the correct amount of green tea to consume to improve weight loss.  However, the greatest insight from this double-blind clinical trial was the difference green tea made in the weight maintenance phase versus high caffeine consumption.”  – Josh Smith

Green Tea and Skin.  Säntosh K. Katiyar, PhD; Nihal Ahmad, PhD; Hasan Mukhtar, PhD.  Arch Dermatol. 2000; 136:989-994. 

Objective: To discuss the current knowledge of polyphenolic compounds present in green tea as anti-inflammatory, antioxidant, and anticarcinogenic in skin. Data Sources: References identified from bibliographies of pertinent articles, including our work in related fields. Study Selection and Data Extraction:  Articles were selected based on the use of green tea or its polyphenolic constituents for prevention against inflammation and cancer in the skin. Also discussed is the possible use of green tea to treat various inflammatory dermatoses. Data Synthesis: The polyphenolic compounds from green tea were tested against chemical carcinogenesis and photocarcinogenesis in murine skin. These green tea polyphenols were found to afford protection against chemical carcinogenesis as well as photocarcinogenesis in mouse skin. A few experimental studies were conducted in human skin in our laboratory. Analysis of published studies demonstrates that green tea polyphenols have anti-inflammatory and anticarcinogenic properties. These effects appear to correlate with antioxidant properties of green tea polyphenols. Conclusions: The outcome of the several experimental studies suggests that green tea possess anti-inflammatory and anticarcinogenic potential, which can be exploited against a variety of skin disorders. Although more clinical studies are needed, supplementation of skin care products with green tea may have a profound impact on various skin disorders in the years to come.

“Finding effective ways to protect our skin is not only good for appearances, but taking care of the largest organ in our bodies is important!  Products that provide support against inflammation and light induced carcinogens should be a the top of everyone’s list!”  – Josh Smith

Green Tea: Nature’s Defense against Malignancies.  Critical Reviews in Food Science and Nutrition, 49:463–473 (2009).  Masood, S.  Sadiq, B.  National Institute of Food Science and Technology, University of Agriculture, Faisalabad.   

The current practice of introducing phytochemicals to support the immune system or fight against diseases is based on centuries old traditions. Nutritional support is a recent advancement in the domain of diet-based therapies; green tea and its constituents are one of the important components of these strategies to prevent and cure various malignancies. The anti-carcinogenic and anti-mutagenic activities of green tea were highlighted some years ago suggesting that it could reduce the prevalence of cancer and even provide protection. The pharmacological actions of green tea are mainly attributed to polyphenols that includes epigallocatechin-3-gallate (EGCG), epicatechin, epicatechin-3-gallate, epigallocatechin. Green tea and its components effectively mitigate cellular damage arising due to oxidative stress. Green tea is supposed to enhance humoral and cell-mediated immunity, decreasing the risk of certain cancers, and may have certain advantage in treating inflammatory disorders. Much of the cancer chemopreventive properties of green tea are mediated by EGCG that induces apoptosis and promotes cell growth arrest, by altering the expression of cell cycle regulatory proteins, activating killer caspases, and suppressing nuclear factor kappa-B activation. Besides, it regulates and promotes IL-23 dependent DNA repair and stimulates cytotoxic T cells activities in a tumor microenvironment. It also blocks carcinogenesis by modulating the signal transduction pathways involved in cell proliferation, transformation, inflammation and metastasis. The review is intended to highlight the chemistry of green tea, its antioxidant potential, its immunopotentiating properties and mode of action against various cancer cell lines that showed its potential as a chemopreventive agent against colon, skin, lung, prostate, and breast cancer.

“Isn’t it interesting that the intensity of the flu and cold season increases at the same time as the over consumption of food and alcohol during the holiday season?  Keep your immune system beefed up during these times by drinking the right amount of green tea on a daily basis.  Daily consumption of green tea can also have anti-inflammatory properties that are far-reaching.”  -Josh Smith