Tea is the most commonly consumed beverage in the world after water. Among all varieties of tea - black, green, white, oolong, red, herbal - which one offers the most health benefits?
Benefits of Tea
Numerous studies have demonstrated the anti-cancer properties of antioxidant polyphenols. Some studies have suggested that tea's polyphenols may reduce the risk of gastric, esophageal and skin cancers, if one consumes 4 to 6 cups daily. Another study showed that just 2 cups of tea may lower the risk of ovarian cancer by 46 percent in women. Other studies have found that polyphenols help prevent blood clotting and lower cholesterol levels. One Japanese study found that green tea lowers death rates from heart disease.
Tea: Black, Green, White or Oolong?
Black, green, white, and oolong teas derive their leaves from a warm-weather evergreen tree known as Camellia sinensis. The leaves from this tree contain polyphenols. The more processing tea leaves undergo, the darker they will turn. Green tea and white tea are the least processed tea. They are simply steamed quickly. According to Dr. Doug Balentine, Director of Nutrition Health with Lipton, white tea is derived from the young new leaves from the Camellia plant in early spring. These young leaves contain no chlorophyll, so they are silvery white. Black and oolong teas are partially dried, crushed and fermented. As we have mentioned before, regardless of the processing method, black, green, white and oolong teas all contain polyphenols. In fact, tea ranks as high as or higher than many fruits and vegetables in the ORAC score, a score that measures antioxidant potential of plant-based foods.
What about Herbal Tea and Red Rooibos Tea?
Herbal tea is not derived from the leaves of the Camellia plant and so does not have the particular health-promoting properties. Indeed, most herbal teas in the market are NOT tea at all. They are only infusions made with herbs, flowers, roots, spices or other parts of some plants. The proper term for this type of beverage is "tisane."
The recently popular South African red Rooibos tea also falls within the herbal tea or tisane category. "Red Rooibos tea is not really tea as it is not derived from the Camellia plant," Dr. Balentine said. They may not contain the same beneficial flavonoid compounds as found in black and green teas. In fact, Dr. Balentine said that "no scientific evidence yet has shown the health benefits of red Rooibos tea."
Although tisane does not contain as any polyphenols, it does promote other various health qualities such as relaxation and calming effects.
Tea: Caffeine content
According to the American Dietetic Association, a cup of tea contains an average of 40 mg of caffeine, compared to 85 mg as found in a cup of freshly brewed coffee.
What about Decaf Tea?
We do not know whether decaf teas have the same polyphenols, and thus the same health benefits. It is not yet known if removing caffeine also removes polyphenols in the decaffeinating process.