These brief reports (selected from many others filed for possible future
use in a book on the subject!) suggest that tea and wine are potentially
powerful health enhancers! My thanks to Simon Martin for helping me
collect these.
Note: Some of these reports are taken from press reports, while others
contain citations as to their original sources. The press reports do not all
offer clear indications as to the origin of the information.
These reports are offered for interest only, and are not meant to be seen
as definitive scientific evidence of benefits or a recommendations for selfapplication.
Tea helps prevent development of chronic disease
Detailed multidisciplinary research on the effect of tea and the associated
tea polyphenols has led to major advances on the underlying mechanisms. In
most studies, green and black tea have similar effects, including :
1) Tea polyphenols are powerful antioxidants that may play a role in
lowering the oxidation of LDL-cholesterol, with a consequent
decreased risk of heart disease, and also diminish the formation of
oxidized metabolites of DNA, with an associated lower risk of specific
types of cancer.
2) Tea and tea polyphenols selectively induce Phase I and Phase II
metabolic enzymes that increase the formation and excretion of
detoxified metabolites of carcinogens.
3) Tea lowers the rate of cell replication and thus the growth and
development of neoplasms.
4) Tea modifies the intestinal microflora, reducing undesirable bacteria
and increasing beneficial bacteria.
The accumulated knowledge suggests that regular tea intake by humans
might provide an approach to decrease the incidence of and mortality from
major chronic diseases
J. H. Weisburger. 1999. Tea and health: the underlying mechanisms.
Proc Soc Exp Biol Med. 220. 4. 271-275 Osteoporosis prevention
Hip fractures related to poor bone mineral density (BMD) are a significant
cause of illness in elderly women. Hegarty et al studied a group of 1256
women ages 65-76 living near Cambridge, UK of whom 1134 were tea
drinkers. Skeletal measurements were taken at the lumbar spine, femoral
neck, greater trochanter, and Ward’s triangle. Tea drinking was highly
associated with greater BMD at all sites with the exception of the femoral
neck. The beneficial effect of tea on BMD occurred independent of factors
such as the addition of milk, coffee drinking, smoking, or the use of hormone
replacement therapy. The tea drinkers overall had a 5% greater mean BMD
than non-tea drinkers. The authors equate this difference with a 10-20%
decline in fracture risk.
Hegarty VM, et al. Tea drinking and bone mineral density in older
women. Am J Clin Nutr 2000; 71:1003-7
Cancer / DNA and tea
Whether tea really helps prevent cancer is still under debate, but research
in its favour is piling up. In one of the largest studies to date, Iowa
researchers found that tea may be a powerful cancer fighter, according to a
study published in the July 1996 issue of the American Journal of
Epidemiology. The study of more than 35,000 postmenopausal women showed
that those who drank at least two cups of black tea a day were 40 percent
less likely to develop urinary tract cancer and 68 percent less likely to
develop cancer in the digestive tract than women who did not drink tea.
Other research shows that tea may be a promising weapon in the fight
against cancers of the stomach, bladder, esophagus and prostate. Moreover,
a study in China concluded that smokers who drink tea have a lower incidence
of lung cancer,
J.H Weisburger Second International Symposium on Tea and Human
Health. April 1999
.
Tea intake is inversely related to blood pressure in older women.University of Western Australia School of Medicine and Pharmacology, and
the Western Australian Institute for Medical Research (WAIMR),Western
Australia, Australia. jonathan@cyllene.edu.au
Tea is rich in polyphenols, which have activities consistent with blood
pressure-lowering potential.
The effects of long-term regular ingestion of tea on blood pressure remain
uncertain.
We investigated the relationships of tea intake and a biomarker of exposure
to tea-derived polyphenols (4-O-methylgallic acid) with blood pressure in a
cross-sectional study of 218 women > 70 y old. Clinic blood pressures were
measured and tea intake was assessed using a 24-h dietary recall; 4-Omethylgallic acid was measured for the same period in a 24-h urine sample.
Mean (95% CI) daily tea intake was 525 (475, 600) mL.
Mean systolic and diastolic blood pressures were 138.1 (135.6, 140.6) and
73.5 (72.1, 74.9) mm Hg. Higher tea intake and higher 4-O-methylgallic acid
excretion were associated with significantly lower systolic (P = 0.002 and P =
0.040, respectively) and diastolic (P = 0.027 and P < 0.001, respectively)
blood pressures. A 250 mL/d (1 cup) increase in tea intake was associated
with a 2.2 (0.8, 3.6) mm Hg lower systolic blood pressure and a 0.9 (0.1, 1.7)
mm Hg lower diastolic blood pressure.
The observed associations for both tea intake and 4-O-methylgallic acid are
consistent with the hypothesis that long-term regular ingestion of tea may
have a favorable effect on blood pressure in older women.
Hodgson JM, Devine A, Puddey IB, Chan SY, Beilin LJ, Prince RL J
Nutr. 2003 Sep;133(9):2883-6.
Black Tea May Help Get Blood Circulating
By Amy Norton
NEW YORK (Reuters Health) – A cup of black tea may give a quick boost to
blood flow to the heart, the results of a small study suggest.
In an experiment with 10 healthy men, Japanese researchers found that
blood-flow in the coronary arteries improved two hours after the men drank
black tea. The same was not true of a caffeinated drink used for comparison.
Numerous studies have suggested that tea drinking may do a heart good,
with effects on cholesterol, blood clotting and blood vessel function being
among the proposed mechanisms.The new study, reported in the American Journal of Cardiology, suggests it
also has a more immediate beneficial effect. The authors suspect that black
tea improved the dilation of the men’s blood vessel, allowing better blood
flow.
Tea is rich in antioxidant compounds called flavonoids, and these may be the
key to the beverage’s potential heart benefits, study co-author Dr. Kenei
Shimada of Osaka City University told Reuters Health.
For the study, the researchers used a special ultrasound method to gauge
“coronary flow velocity reserve” or CFVR. This reflects how much blood-flow
can speed up when demands are put on the heart, and paints a picture of the
healthiness of the coronary circulation.
Shimada’s team measured the CFVR of each of the men after they drank
either black tea or a caffeinated beverage, and found that it increased
significantly after the black tea.
“The results of this study suggest that black tea consumption has a
beneficial effect on coronary circulation,” the researchers report.
They speculate that the flavonoids in black tea improve the functioning of
the lining of the blood vessels, increasing how much the vessels dilate in
response to blood flow. Dysfunction in this lining, called the endothelium, is
one of the things that goes wrong as heart disease develops.
It’s not clear what the long-term implications of the findings on CFVR might
be, but Shimada said research has shown coronary flow reserve to be
related to heart disease risk.
Larger studies, particularly in people with coronary artery disease, are
needed to establish how tea affects the coronary circulation, the
researchers conclude.
American Journal of Cardiology, June 1, 2004
Tea and HIV
Tea May Offer Treatment to Fight HIV – Japan Study
by Christopher Doering
WASHINGTON (Reuters) – Japanese researchers said on Monday they had
discovered a molecule in tea that could block the spread of the AIDS
The lab findings could offer a novel way to combat the HIV infection by
preventing the virus from spreading throughout the body, scientists said.
Current treatments that target HIV fight the infection after it has spread.
Scientists at the University of Tokyo, led by Kuzushige Kawai, found a
compound called epigallocatechin gallate or EGCG, the element believed to contain most of the health benefits found in green tea, rapidly attaches to
the doorways that the AIDS virus uses to invade cells.
HIV prefers to infect cells called CD4 T-cells, and uses a molecular doorway
called the CD4 receptor to do so.
By bonding with the CD4 molecule first, EGCG effectively prevents the HIV
virus from attaching — at least in lab dishes.
“This potentially opens up an avenue for preventing HIV infections,” said Dr.
William Shearer, a professor at Baylor College of Medicine in Houston, who
wrote an editorial that accompanied the study. “Is there something here
that mother nature is trying to tell us?”
Writing in the Journal of Allergy and Clinical Immunology, the researchers
said they are still looking to explain why EGCG is attracted to CD4 molecule,
in the hope of making it work even better.
Earlier studies have showed that people who drink a lot of tea have lower
rates of cancer, heart disease and rheumatoid arthritis. In September, the
U.S. Department of Agriculture found people who drank black tea saw their
cholesterol drop between 7 and 11 percent.
Simply drinking tea would probably not be enough to prevent HIV infection,
Shearer said. If EGCG is shown to work in a living animal, it would have to be
concentrated, perhaps in a pill.
The lab study found that EGCG attached to 80 percent of CD4 receptors
after five minutes and to virtually all of them after 30 minutes.
The popularity of tea has soared during the last decade.
According to the Tea Association of the United States, total sales of tea in
2002 were $5.03 billion, up from $1.84 billion in 1990.
Catechin inhibits tumour formation
Catechins, found abundantly in fruits and vegetables are powerful
antioxidants (Nakao 1998)
Microscopic imaging of colon cancer cells showed organized actin stress
fibres, characteristic of adherent cells, became ‘reorganised’, when treated
with catechin. Same study showed catechin reduced the invasive capacity of
HT-29 colon cancer cells and also modulates integrin-mediated signaling in
colorectal cancer cell lines, in enterocytes and tumours. (Weyant 2001)
Catechin is readily absorbed. A good source is red wine, where fermentation
enhances bioavailability. Effective dosage is estimated to be contained in
500ml red wine daily (less if diet contains apples, onions, grapes,
chocolate)(Hackett 1983, Bell 2000) Nakao M et al 1998 Alkyl peroxy radical scavenging activity of catechins
Phytochemistry 49:2379-2382
Weyant M et al 2001 Catechin inhibits intestinal tumor formation Cancer
Research 61:118-125
Hackett A et al 1983 Metabolism and excretion of [catechin] in man
following oral administration. Xenobiotica 13:279-286.
Bell J et al 2000 Catechin in human plasma after ingestion of single
serving reconstitute
White wine does you good
(London Times May 21 2002)
Mark Henderson – Science Correspondent
Researchers at The University of Buffalo found that people who drink a few
glasses of white wine on a regular basis have stronger lungs than those who
never touch it. The results of the study were presented (20 May 2002) at
The American Thoracic Society’s annual conference in Atlanta, Georgia.
Holger Schunemann, the study’s leader, said: “This finding may indicate that
nutrients in wine are responsible for the positive effect of alcoholic
beverages on lung function. Red wine in moderation has been shown to be
beneficial for the heart, but in this case the relationship was stronger for
white wine.”
1,555 volunteers completed questionnaires that assessed alcohol
consumption and other aspects of their lifestyles.
They then took two standard lung-function tests that measured forced vital
capacity (FVC) — and the volume that can be expelled in one second (FEV1).
Both a recent and a lifetime history of moderate wine drinking, particularly
with white wine, were associated with high readings for FVC and FEV1 lung
capacity.
The benefits probably come from compounds such as phenols and flavonoids,
abundant in wine, which reduce oxidative stress..
