By Dr. Mercola
Pure water is by far the ideal beverage of choice, but high-quality tea can be a valuable addition. Not only does tea rehydrate as well as water does, most teas also have additional health benefits.1
High-quality tea—green tea in particular—contains polyphenol antioxidants that are recognized for their disease prevention and anti-aging properties. Polyphenols can account for up to 30 percent of the dry leaf weight of green tea.
Within the group of polyphenols are flavonoids, which contain catechins. One of the most powerful catechins is epigallocatechin-3-gallate (EGCG), found in green tea. EGCG has been shown to positively impact a number of illnesses and conditions.
Previous research2 has shown that green tea polyphenols act on molecular pathways to shut down the production and spread of tumor cells. They also discourage the growth of the blood vessels that feed the tumors.
EGCG even acts as an antiangiogenic and antitumor agent, and helps modulate tumor cell response to chemotherapy.3 Study results also show EGCG can be helpful for the prevention of arteriosclerosis, cerebral thrombus, heart attack, and stroke—in part due to its ability to relax your arteries and improve blood flow.4
Green Tea Lowers Blood Pressure Naturally
Some of the latest research in this area again confirms such health benefits. After analyzing 25 randomized controlled trials, the systematic review, published in the British Journal of Nutrition in October5 concluded that long-term tea intake significantly improved blood pressure. As reported in Time Magazine:6
“After 12 weeks of drinking tea, blood pressure was lower by 2.6 mmHg systolic and 2.2 mmHg diastolic. Green tea had the most significant results, while black tea performed the next best...
Reducing systolic blood pressure by 2.6 mmHg ‘would be expected to reduce stroke risk by 8 percent, coronary artery disease mortality by 5 percent and all-cause mortality by 4 percent at a population level...’”
While unable to determine exactly how much tea you need to drink to receive these benefits, a number of previous studies have suggested the ideal amount lies around three to four cups of tea per day.7
For example, one 2007 study8 found “clear evidence” showing that three or more cups of tea—in this case black tea—reduced the risk of coronary heart disease.
Similarly, drinking three to four cups of green tea daily has been shown to promote heart and cardiovascular health,9 again courtesy of its ability to relax blood vessels and protect against blood clots.
Green Tea—Helpful Against Obesity, Diabetes, and Alzheimer’s Disease
There are certain compounds and nutrients that seem to have near limitless health potential, and catechins are part of that pack. Fortunately, high-quality green tea is an excellent source of these antioxidants, making them easily available.
Besides its beneficial effects on your circulatory system, previous studies have demonstrated that EGCG in particular has a regulatory effect on fat metabolism, thereby increasing fat oxidation and preventing obesity. It can even help improve exercise performance.
One 2010 study10 evaluating EGCG’s potential in weight loss found it increases fat oxidation by a respectable 33 percent. EGCG may also aid weight loss by inhibiting fat cell development and increasing fat excretion. Obesity and diabetes tend to go hand in hand, and what is beneficial for one is usually beneficial for the other as well.
Indeed, one animal study11 found that EGCG was as effective as the diabetic drug Avandia in moderately diabetic mice, suggesting green tea, or a high-quality green tea extract, could be helpful for the prevention and/or treatment of diabetes.
Researchers have also discovered that green tea has the potential to enhance the function of your brain, and prevent age-associated brain degeneration.
Specifically, EGCG appears to decrease the production of the protein beta-amyloid, which can over-accumulate in your brain, resulting in nerve damage and memory loss over time12 – a condition related to Alzheimer’s disease.
In one study,13 published in 2005, researchers injected pure EGCG into mice genetically programmed to develop Alzheimer’s; the results showed a decrease of as much as 54 percent in the plaque associated with Alzheimer’s.
Other Health Benefits of Green Tea
Catechins in green tea may also help protect against glaucoma and other eye diseases. In one study,14 scientists analyzed eye tissue from rats that drank green tea and found that eye tissues such as the lens and retina had in fact absorbed green tea catechins.
According to the authors, oxidative stress causes biological disturbances such as DNA damage and activation of proteolytic enzymes that can lead to tissue cell damage or dysfunction—and, eventually, ophthalmic diseases. Green tea catechins have also been found to:
- Lower your breast cancer risk
- Ease inflammation and pain associated with rheumatoid arthritis (RA)15
- Reduce your risk of autoimmune diseases
- Promote healthy gums
- Improve digestion
A botanical ointment containing a green tea extract was even found to be an effective treatment for external genital and anal warts, according to the results of one 2008 study.16 Genital and anal warts are caused by human papillomavirus (HPV), and there has been a lack of effective, well tolerated treatments.
The researchers assigned over 500 adults with up to 30 warts to receive either an ointment containing sinecatechins, or a placebo. In the sinecatechins groups, warts cleared completely in roughly 57 percent of patients, compared to just 34 percent of subjects in the control group.
Quality Green Tea Is Green
Out of the seemingly endless varieties of tea out there, there is only a handful I would recommend drinking. My two favorites are Matcha green tea and Tulsi—a powerful adaptogenic herb that also provides important therapeutic benefits.
Green tea in general is among the least processed kinds of tea, which is why it contains some of the highest amounts of EGCG. Unlike other teas that you steep and strain, Matcha tea comes in the form of a powder that you add right into the water.
Matcha tea can contain over 100 times the EGCG provided by regular brewed green tea, and since you’re consuming the entire ground tea leaf, you’re getting the most benefit from each cup of tea you drink.
Besides being an excellent source of antioxidants, green tea is also packed with vitamins A, D, E, C, B, B5, H, and K, manganese, and other beneficial minerals such as zinc, chromium, and selenium. A telltale sign of high quality is that the tea is in fact green. If your green tea looks brown rather than green, it’s likely been oxidized, which can damage or destroy many of its most valuable compounds.
To boost the benefits of green tea, add a squirt of lemon juice to your cup. Previous research has demonstrated that vitamin C significantly increases the amount of catechins available for your body to absorb. In fact, citrus juice increased available catechin levels by more than five times, causing 80 percent of tea's catechins to remain bioavailable!
Tea Can Be a Valuable Part of a Healthy Diet
If you enjoy green tea, by all means add a few cups to your day. Just be sure to drink your green tea “straight.” Adding sugar, milk, or other “embellishments” (one exception being some citrus juice), will counter many of the benefits of the tea. Again, green tea contains the most EGCG of all tea varieties, and other than water, I believe high-quality green tea is one of the most beneficial beverages you can consume.
Another excellent choice is Tulsi tea, which is also chockfull of antioxidants. The complex and unique chemistry of this aromatic herb also offers benefits that go over and beyond that of other teas. Tulsi tea contains hundreds of beneficial compounds known as phytochemicals—non-nutritive plant compounds that have protective and health promoting properties. Working together, these compounds possess potential antioxidant, adaptogenic, and immune-enhancing properties that can fight stress and help promote your general health in multiple ways, including:
- Bolstering your immune system
- Providing you with a calming effect and relief from occasional stress
- Promoting healthy metabolism
- Helping maintain optimal blood sugar levels
- Supporting normal cholesterol levels