Unlike the Philippines, tea has long been regarded in countries such as Britain, China, Japan, and Indonesia as an elixir of good health, and with good reason. Consumption of some teas may be protective against heart disease, diabetes, and certain cancers; and it can boost immune function, improve mental alertness, and increase satiety, as some research suggests. So, Filipinos may need to start steeping and sipping more tea if we want to be healthier!
“If there’s anything that can confidently be communicated to the public, it’s the strong association of tea drinking with a lower risk of common chronic diseases, particularly heart disease, and the demonstration of that benefit through clinical trials,” says Jeffrey B. Blumberg, PhD, director of the Human Nutrition Research Center on Aging at Tufts University in Boston, and chair of the International Scientific Symposium on Tea and Human Health, held in Washington, DC recently.
The symposium spotlighted new evidence of the health benefits of tea, ranging from preventing osteoporosis to improving digestion. Other new studies have recently linked tea consumption to lower incidence of some cancers and reduced risk of functional disability.
Why is tea good for you? All types of tea made from the leaves of the Camellia sinensis plant, while varying in their nutritional profiles, contain antioxidant compounds called flavonoids. “About one-third of the weight of the tea leaf is flavonoid, which is high, especially when you consider that they are accompanied by virtually no calories,” Blumberg explains. “There are a lot of related flavonoids in fruits and vegetables, but many people are not consuming the amount of flavonoids in their diets that have been found necessary to promote health. Another way to get them is to drink tea. A cup of tea is like adding a serving of fruits or vegetables to your diet.”
What is Tea?
All true, non-herbal tea comes from the leaves of the Camellia sinensis plant. The different types of tea derived from this plant depend on how the leaves are processed. Black tea is dried, fermented, and fully oxidized. Green tea is unfermented and minimally processed; the leaves are simply withered and steamed. Oolong tea is partly oxidized. White tea is made from partly opened buds and young leaves, which are steamed and then dried. Black and green tea have been studied the most extensively for health benefits.
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To get the most flavonoids from tea, steep in hot water. Cold-brewed tea and powdered mixes generally don’t achieve the same flavonoid levels. Brew green tea at 175 to 185ºF, oolong at 195ºF, and black tea in boiling water (212ºF). If you don’t like your tea plain, opt for lemon or other citrus juice instead of milk or cream. Besides adding little or no calories, citrus juices reduce the loss of tea flavonoids through digestion. Other important aspects of how to best prepare tea and the right amount to drink for health purposes is shown in the accompanying illustration (Tea Talk).
Blood pressure benefits
A small study presented at the symposium added to the evidence that all those flavonoids are good for your heart. Men with high blood pressure who drank just one cup of black tea daily saw lower systolic and diastolic blood pressure levels — even when they ate a meal of fatty, sugary foods, which tend to constrict blood vessels and boost blood pressure.
“If we were able to reduce blood pressure just slightly and shift the entire population to a lower blood pressure,” Blumberg says, “that would have a significant impact in terms of reduced number of people with hypertension and its consequences for cardiovascular disease. Small, modest, long-term benefits on blood pressure can be very important from the public-health point of view.”
An earlier meta-analysis published in the American Journal of Epidemiology concluded that drinking three cups of tea daily was associated with an 11-percent drop in the risk of heart attacks. Other studies have suggested that green tea might help improve cholesterol and triglyceride levels.
Better bones. Living independently
Perhaps surprisingly, drinking tea might also be good for your bones. Another new study, by researchers at Texas Tech University reported that green tea boosted bone formation in postmenopausal women with low bone mass. Scientists tested 171 women given 500 mg daily of green tea polyphenol capsules — the equivalent of about four to six cups of tea. After six months, the women showed indications of improved bone formation and muscle strength, which could reduce the risk of falls and fractures, and a reduction in cell damage from oxidative stress.
Tea drinking could likewise improve your overall ability to live independently — affected not only by osteoporosis but factors such as stroke and cognitive impairment. A recent Japanese study on “functional disability” published in the American Journal of Clinical Nutrition followed 14,000 older adults for three years. Those who reported consuming five or more cups of green tea daily were only a little more than half as likely to develop functional disability than those drinking less than a cup daily.
Brew for your brain
Tea seems to help protect the aging brain in a variety of ways. Cardiovascular effects, of course, also benefit the brain by better blood flow. Animal tests have even shown that tea extracts reduce the damage to the brain from strokes.
Other animal experiments suggest that compounds in tea can help counter the loss of neuronal plasticity — the brain’s ability to adapt to new inputs — and repair injuries to the brain’s neurons associated with aging. Green tea may specifically benefit the hippocampus, a part of the brain that’s important to memory. In a 2011 study on humans with mild memory impairment, a daily supplement of green tea extract plus L-theanine (an amino acid unique to tea) over four months improved memory and mental alertness better compared to a placebo. Most recently, a study using functional MRI scans found that green tea extract affected activity in an area of the brain that is key to memory processing.
Could tea even help protect against or slow the progression of Alzheimer’s disease? Researchers have shown that tea compounds bind to the beta-amyloid proteins associated with Alzheimer’s.
Reducing cancer risk
Researchers have also looked to tea-drinking countries such as China for possible cancer-fighting benefits of tea consumption. Recently, the Shanghai Women’s Health Study reported findings that regular tea intake was associated with a lower risk of digestive-system cancers.
Scientists followed 69,310 women who didn’t smoke or drink alcohol for an average of 11 years during which 1,255 digestive-system cancers were diagnosed. Overall, regular tea intake (mostly green tea) was associated with a reduced risk of these cancers. Among women who averaged more than two or three cups of tea daily, the risk of all digestive-system-cancers was 21 percent lower. The reduction in risk was even better with higher tea consumption and more years of drinking tea.
More Tea benefits
Other recent research continues to broaden the spectrum of possible benefits from drinking tea. For example:
• Dutch researchers report that a combination of green tea flavonoids and caffeine increases calorie expenditure and fat oxidation. By burning an extra 100 calories a day, this tea duo provided a loss of 2.8 pounds in 12 weeks.
• The L-thianine in tea, plus caffeine, has been found to reduce levels of a stress hormone called cortisol, while also improving mental alertness.
• Tea flavonoids can encourage healthy bacteria in the gastrointestinal tract, much as probiotics do.
• Countries with the highest rates of black tea consumption, according to a 2012 study, have lower rates of type-2 diabetes.
It’s possible to get too much of a good thing, especially if you’re sensitive to caffeine. But tea contains only about half the caffeine of coffee, and most of tea’s benefits can be derived from decaffeinated teas (though some of the flavonoid content is lost in the decaf process).
Blumberg sums it up when he said: “If you don’t drink tea, you should start. It’s really delicious. It’s convenient. And it has zero calories!”
