Human population studies have found that people who regularly consume three
or more cups of Black Tea per day have reduced risk of heart disease and stroke.
Clinical studies suggest that the risk reduction associated with Black Tea
consumption may be due to improvement in some risk factors for cardiovascular
disease, including blood vessel function, platelet function and a reduction in
oxidative damage.

While researches are still examining the various mechanisms by which tea
flavonoids function, some studies suggest multi functional mechanisms,
meaning that several mechanisms work in tandem to collectively improve
markers for cardiovascular health. Important areas of tea and cardiovascular
health research include blood vessel and endothelial function, or the ability of
the blood vessels to dilate to allow for proper blood flow, serum cholesterol
levels and Low Density Lipoprotien (LDL) cholesterol oxidation. Each of these
factors impact the risk of myocardial infarctions (heart attacks), stroke and
cardiovascular disease. Study findings in the area of tea and the reduction in
cardiovascular disease risk include the following:

Coronary Heart Disease (CHD)

Cardiac Events
* A total of 3,430 men and women aged 30-70 years from the Saudi Coronary
Artery Disease Study were examined and 6.3 percent were found to have
indications of coronary heart disease (CHD). The researchers found that those
who drank more than six cups of tea per day (>480 mg) has significantly lower
prevalence of CHD than non-tea drinkers, even after adjustment for rick factors
like age and smoking. The researchers also found that drinking six or more cups
of Black Tea per day was associated with decreased serum cholesterol and
triglyceride concentrations.

*The Zutphen study, which assessed 05 male subjects over a period of five years,
found that the incidence of fatal and nonfatal first myocardial infarction and
mortality from stroke decreased significantly as intake of flavonoids, derived
mainly from tea, increased in a dose-dependant manner. A follow-up to this
study found that high intake flavonoids significantly lowered the risk of stroke
in study participants.

*A Harvard study examined 340 men and women who had suffered heart
attacks and compared them to matched control subjects. They found that those
who drank a cup or more of Black Tea daily had a 44 percent reduction in the
risk of heart attack compared to non-tea drinkers.

*Another recent Harvard study of 1,900 people found that those who consumed
tea during the year prior to a heart attack were up to 44 percent more likely to
survive over the three to four years following the event. Those who consumed
fewer than 14 cups of tea per week experienced a 28 percent reduced death
rate and those who consumed more than 14 cups of tea per week were found to
have a 44 percent reduced death rate, as compared to non-tea drinkers.

*Dutch researchers assessed 4,807 subjects aged 55 years or older without prior
history of heart attack. After a four to seven year follow up period, the
researchers determined that those who drank three or more cups of tea per day
(357 mL) were 43 percent less likely to develop myocardial infarction and 70
percent less likely to die from myocardial infarction than non-tea drinkers.

* A recent meta-analysis discovered that consumption of three cups of tea per
day was associated with an estimated decrease of 11 percent in the incidence of
myocardial infarction, of heart attack.

Cholesterol Reduction
Researchers from the United States Department of Agriculture (USDA) studied
the effect of tea on 15 mildly hypercholesterolemic  adult participants following
a "step I" type diet moderately low in fat and cholesterol, as described by the
American Heart Association and the National Cholesterol Education Program.
After weeks, researchers found that fiver servings of Black Tea per day reduced
LDL ("bad") cholesterol by 11.1 percent and total cholesterol (TC) by 6.5 percent
compared to placebo beverages. Recent clinical trails have not confirmed these
results. However additional work is being done in this area.

Tea and Cardiovascular Disease (CDV) Risk Factors
*Dutch researchers found that study participants who drank one to two cups of
Black Tea daily had a 46 percent lower risk of severe aortic  atherosclerosis, a
strong indicator of cardiovascular disease. Those who drank more than four cups
of tea a day had a 69 percent lower risk.

* A recent clinical study showed that short- and long-term consumption of Black
Tea by subjects with coronary artery disease restored endothelial and blood
vessel function to levels similar to that of healthy subjects. Endothelial function
is the ability of the inner lining of blood vessels to dilate in response to
increased blood flow.

*Another clinical study found that regular ingestion of tea resulted in a
significant and consistent increase in enothelium-dependent and
endothelium-independent blood vessel dilation. Subjects with mild elevations in
serum cholesterol or triglyceride concentrations consumed either five cups of
Black Tea per day for four weeks or hot water. The researchers hypothesized that
one mechanism for the apparent beneficial effects of tea on cardiovascular
health could be this improved vasodilator function.

*An in vitro study found that Green Tea polyphenols inhibit the proliferation of
aortic smooth muscle cells to prevent the development of atherosclerosis.

* In Vitro studies have shown that tea flavonoids protect low-density
lipoproteins from oxidation, inhibit plasma lipid peroxidation, platelet
aggregation and thromboxane formation- all factors important for maintaining a
healthy circulatory system. Studies in animals are promising, but human studies
conducted to date on the effect of tea consumption on LDL oxidation are
inconclusive.

*A double-blind crossover design clinical study found that Black Tea versus a
caffeinated control beverage improved coronary flow velocity reserve, a
measure of increased blood flow in vessels.

*Animal model studies found that Green and Black Tea both improved risk
factors for CVD, including reduced blood lipids, serum antioxidants levels and
improvements in blood clotting factors.

* A longitudinal study with more than 1,500 Taiwanese found that those who
drank more than 2 1/2 cups of tea per day reduce their risk of developing high
blood pressure by 65 percent compared to those who drank the least amount of
tea.
Tea's Role in Cardiovascular Health