Tea is one of the most highly drunk beverage in the world, second only to water. There are four true teas: black tea, green tea, oolong tea and white tea.

A German study in 2006 stated that the addition of milk in teas, prevented vasular protective effects.
Benefits of drinking tea include:
Anti-Cancer Properties
There have been many studies to support this claim and more studies are being carried out to support this claim. Lung, prostate and breast cancer were the main cases studied.
Increase Metabolic Rate
Clinical studies have shown that green tea raises metablic rates, speeds up fat oxidation and improves insulin sensitivity and glucose tolerance.
Possible Anti-Diabetes Effect
There are on-going studies of the effect of drinking green tea that may help prevent diabetes.
Boosts Mental Alertness
In September 2007, John Foxe, Ph.D concluded his study and found that theanine, found exclusively in tea, increases alpha brain-wave activity. The result is a calmer, yet more alert state of mind.
Boots Immune System

On April 21, 2003, the Brigham and Women's Hospital concluded that the production of anti-bacterial proteins was higher in tea-drinkers than coffee drinkers. This indicates that tea drinkers have a stronger immune response.
Lowers Chances of Cognitive Impairment
Elderly Japanese people who consumed more than 2 cups of green tea a day had 50% lower chance of having lower cognitive impairment. This was revealed in a 2006 study.
Lowers Stress Hormone Levels
Drinking black tea lowers stress hormone levels were revealed in a study by UCL researchers.
Effects on HIV
A recent study found that drinking Green Tea can lead to the inhibition of HIV virus binding, thus may be used as a complementary therapy for HIV patients.
Effects on Bad Breath
Drinking tea help to inhibit the growth of bacteria that causes bad breath.
Other Effects Associated with Caffeine

Other caffeine consumption benefits include greater athletic performance, healthy weight loss, reduction in duration an severity of headaches and its effect on treating the symptoms of asthma.