Clinical studies suggest that green tea may boost your metabolism and help you burn fat. Green tea can also help you lose weight and lower your risk of becoming overweight or obese. Much of this effect is likely due to caffeine, but other compounds in tea may also contribute to this effect. By helping you selectively burn the fat you have stored in your body for energy, green tea may help you feel fuller and maintain a more steady energy level, resulting in less hunger cravings and less calories consumed.
In 2009, King’s College researchers found that epicatechin may protect brain cells through mechanisms unrelated to its antioxidant ability, as epicatechin is one of the few flavonoids that can cross the blood-brain barrier. The King’s College researchers reported that somehow epicatechin protects brain cells from the negative effects of beta-amyloid plaques, although the exact mechanism of how this works is still not entirely know. (9)
Sencha: Sencha comes from the same plant, but in this green tea variation, the leaves are from the middle of the branch and are bigger, older, and less tender than Gyokurocha. This variety gives a clear, light green tea when brewed as well. Naturally, it is more bitter and stronger than the former variety. Being of less noble origin (middle of the branch) and having more caffeine and tannin, it is cheaper and more popular than Gyokurocha.
Green tea is processed using either artisanal or modern methods. Sun-drying, basket or charcoal firing, or pan-firing are common artisanal methods. Oven-drying, tumbling, or steaming are common modern methods. Processed green teas, known as aracha, are stored under low humidity refrigeration in 30- or 60-kg paper bags at 0–5 °C (32–41 °F). This aracha has yet to be refined at this stage, with a final firing taking place before blending, selection and packaging take place. The leaves in this state will be re-fired throughout the year as they are needed, giving the green teas a longer shelf-life and better flavor. The first flush tea of May will readily store in this fashion until the next year's harvest. After this re-drying process, each crude tea will be sifted and graded according to size. Finally, each lot will be blended according to the blending order by the tasters and packed for sale.
Rooibos is being heavily hyped by producers and distributors as a new health beverage. Unlike true “tea,” it is caffeine-free and low in tannins. It contains minimal amounts of calcium, potassium, iron, zinc, magnesium and much less fluoride than found in real teas. Studies have shown that Rooibos does contain antioxidants and therefore might have some of the health benefits of green tea, but very little research has confirmed this. I found only 17 scientific studies of Rooibos compared to more than 1,000 on green tea. So far, none suggest that Rooibos is the health equivalent of green tea.
One thing to watch out for in detox teas, though, is a common ingredient—and herbal laxative—senna. “One part of detoxing is the cleansing of the intestines, and senna aids this process,” he explains. While it can be helpful as a night-time drink short-term, taking senna for too long can cause vomiting, diarrhea, electrolyte imbalance, and dehydration. If you feel stopped up, incorporate a senna tea for a few nights (Villacorta recommends Traditional Medicinals Organic Smooth Move). But stick to senna-free varieties for your habitual cup.
Matcha, the focal point of the Japanese Tea Ceremony, is a fine powder made by grinding green tea leaves. Only the finest, young, shade-grown gyokuro tea leaves are used to create matcha. The leaves are plucked and laid out flat to dry. Veins are removed and the leaves, now called tencha, are carefully ground in granite mills until they become the precious powder. Easy preparation is achieved by placing 1 teaspoon of matcha per cup (or to taste) in a cup, adding a few drops of hot water (160-180F) and stirring with a spoon until a paste forms. Add the rest of the water and stir.
Apart from causing premature aging, free radicals are also responsible for causing certain types of cancer. The catechins present in green tea neutralize these free radicals, prevent the formation of carcinogens like nitrosamines and reduce the risk of cancer for people who regularly consume it. Green tea is now being clinically used and prescribed as a home remedy to aid in the prevention of cancer, particularly for those patients at high risk for cancer in the colon, rectum, pancreas, and intestines.