X-Message-Number: 31300
Date: Wed, 24 Dec 2008 10:23:35 -0800 (PST)
From: 
Subject: green tea may increase human lifespan

[Green tea is associated with reduced cognitive impairment, and
reduced mortality rates in humans. It even grows hair!]

JAMA. 2006 Sep 13;296(10):1255-65.
Comment in:  Forsch Komplement Med (2006). 2007 Apr;14(2):111-2.
                   JAMA. 2007 Jan 24;297(4):360; author reply 360-1.
Green tea consumption and mortality due to cardiovascular disease, cancer,
and all causes in Japan: the Ohsaki study.
  Kuriyama S, Shimazu T, Ohmori K, Kikuchi N, Nakaya N, Nishino Y, Tsubono
Y, Tsuji I. Division of Epidemiology, Department of Public Health and
Forensic Medicine, Tohoku University Graduate School of Medicine, Sendai,
Japan.
  CONTEXT: Green tea polyphenols have been extensively studied as
cardiovascular disease and cancer chemopreventive agents in vitro and in
animal studies. However, the effects of green tea consumption in humans
remain unclear. OBJECTIVE: To investigate the associations between green tea
consumption and all-cause 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. MAIN OUTCOME MEASURES: Mortality
due to cardiovascular disease, cancer, and all causes. RESULTS: Over 11
years of follow-up (follow-up rate, 86.1%), 4209 participants died, and over
7 years of follow-up (follow-up rate, 89.6%), 892 participants died of
cardiovascular disease and 1134 participants died of cancer. Green tea
consumption was inversely associated with mortality due to all causes and
due to cardiovascular disease. 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 were 1.00 (reference) for
less than 1 cup/d, 0.93 (95% confidence interval [CI], 0.83-1.05) for 1 to 2
cups/d, 0.95 (95% CI, 0.85-1.06) for 3 to 4 cups/d, and 0.88 (95% CI,
0.79-0.98) for 5 or more cups/d, respectively (P = .03 for trend). The
corresponding data for women were 1.00, 0.98 (95% CI, 0.84-1.15), 0.82 (95%
CI, 0.70-0.95), and 0.77 (95% CI, 0.67-0.89), respectively (P<.001 for
trend). 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.
PMID: 16968850

Am J Clin Nutr. 2006 Feb;83(2):355-61.
Green tea consumption and cognitive function: a cross-sectional study from
the Tsurugaya Project 1.
Kuriyama S, Hozawa A, Ohmori K, Shimazu T, Matsui T, Ebihara S, Awata S,
Nagatomi R, Arai H, Tsuji I.
Division of Epidemiology, Department of Public Health and Forensic Medicine,
Tohoku University Graduate School of Medicine, Sendai, Japan.

BACKGROUND: Although considerable experimental and animal evidence shows
that green tea may possess potent activities of neuroprotection,
neurorescue, and amyloid precursor protein processing that may lead to
cognitive enhancement, no human data are available. OBJECTIVE: The objective
was to examine the association between green tea consumption and cognitive
function in humans. DESIGN: We analyzed cross-sectional data from a
community-based Comprehensive Geriatric Assessment (CGA) conducted in 2002.
The subjects were 1003 Japanese subjects aged > or =70 y. They completed a
self-administered questionnaire that included questions about the frequency
of green tea consumption. We evaluated cognitive function by using the
Mini-Mental State Examination with cutoffs of <28, <26, and <24 and
calculated multivariate-adjusted odds ratios (ORs) of cognitive impairment.
RESULTS: Higher consumption of green tea was associated with a lower
prevalence of cognitive impairment. At the <26 cutoff, after adjustment for
potential confounders, the ORs for the cognitive impairment associated with
different frequencies of green tea consumption were 1.00 (reference) for <
or =3 cups/wk, 0.62 (95% CI: 0.33, 1.19) for 4-6 cups/wk or 1 cup/d, and
0.46 (95% CI: 0.30, 0.72) for > or =2 cups/d (P for trend = 0.0006).
Corresponding ORs were 1.00 (reference), 0.60 (95% CI: 0.35, 1.02), and 0.87
(95% CI: 0.55, 1.38) (P for trend = 0.33) for black or oolong tea and 1.00
(reference), 1.16 (95% CI: 0.78, 1.73), and 1.03 (95% CI: 0.59, 1.80) (P for
trend = 0.70) for coffee. The results were essentially the same at cutoffs
of <28 and <24. CONCLUSION: A higher consumption of green tea is associated
with a lower prevalence of cognitive impairment in humans.
PMID: 16469995

Phytomedicine. 2007 Aug;14(7-8):551-5. Epub 2006 Nov 7.
Human hair growth enhancement in vitro by green tea
epigallocatechin-3-gallate (EGCG).
Kwon OS, Han JH, Yoo HG, Chung JH, Cho KH, Eun HC, Kim KH.
Department of Dermatology, Seoul National University College of Medicine,
Laboratory of Cutaneous Aging and Hair Research, Seoul National University
Hospital, Institute of Dermatological Science, Seoul National University,
110-744 Seoul, Republic of Korea.

Green tea is a popular worldwide beverage, and its potential beneficial
effects such as anti-cancer and anti-oxidant properties are believed to be
mediated by epigallocatechin-3-gallate (EGCG), a major constituent of
polyphenols. Recently, it was reported that EGCG might be useful in the
prevention or treatment of androgenetic alopecia by selectively inhibiting
5alpha-reductase activity. However, no report has been issued to date on the
effect of EGCG on human hair growth. This study was undertaken to measure
the effect of EGCG on hair growth in vitro and to investigate its effect on
human dermal papilla cells (DPCs) in vivo and in vitro. EGCG promoted hair
growth in hair follicles ex vivo culture and the proliferation of cultured
DPCs. The growth stimulation of DPCs by EGCG in vitro may be mediated
through the upregulations of phosphorylated Erk and Akt and by an increase
in the ratio of Bcl-2/Bax ratio. Similar results were also obtained in in
vivo dermal papillae of human scalps. Thus, we suggest that EGCG stimulates
human hair growth through these dual proliferative and anti-apoptotic
effects on DPCs.
PMID: 17092697 [PubMed

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