Tea is the most widely consumed beverage in the world next to water, and can be found in almost 80% of all U.S. households. It is the only beverage commonly served hot or iced, anytime, anywhere, for any occasion.
Black, Green, Oolong, Dark and White teas all come from the same plant, a warm-weather evergreen named Camellia sinensis. Differences among the five types of tea result from the various degrees of processing and the level of oxidization. Black tea is fully oxidized and Oolong teas are partially oxidized. After withering and rolling, the tea leaves undergo natural chemical reactions resulting in taste and color changes and that develop the teas distinguishing characteristics. Green & White teas are not oxidized after leaf harvesting. Oolong tea is midway between Black and Green teas in strength and color.
Tea is nearly 5,000 years old. It was discovered in 2737 BC by Chinese Emperor Shen-Nung, also known as the "Divine Healer," when as legend goes, some tea leaves accidentally blew into the Emperor's pot of boiling water.
In the 1600's, tea became highly popular throughout Europe and the American colonies. Tea played a dramatic part in the establishment of the United States of America. In 1767 the British Government put a tax on the tea used by American colonists. Protesting this "taxation without representation," the colonists decided to stop buying tea and refused to allow tea ships to be unloaded. One December night in 1723, men dressed as Native Americans boarded British ships in Boston Harbor and threw more than 300 chests of tea into the sea. While not the only instance of teas being thrown overboard in protest of the British tax on tea, this most famous Boston Tea Party was said to be a principle act leading to the Revolutionary War.
The U.S. played an important role in the history of tea, inventing the tea bag and iced tea, both in 1904. Recently, the U.S. has led the rest of the world in marketing convenient Ready-To-Drink forms of tea in bottles.
Tea is an all-natural and environmentally sound product from a renewable source. The tea plant is naturally resistant to most insects; oxidation of the tea leaf is a natural process; and, many tea packers use recycled paper for packaging.
Tea is naturally low in caffeine. A cup of Black Tea, for example, contains about 40 milligrams of caffeine. Tea is a refreshing beverage that contains no sodium, fat, carbonation, or sugar. It is virtually calorie-free. Tea helps maintain proper fluid balance and may contribute to overall good health. Tea contains flavonoids, naturally occurring compounds that are believed to have antioxidant properties. Tea flavonoids often provide bioactive compounds that help to neutralize free radicals, which scientists believe, over time, damage elements in the body, such as genetic material and lipids, and contribute to chronic disease.
Every day, new findings from the international scientific community lend credibility to tea's healthy properties. Recent research has explored the potential health attributes of tea through studies in humans, animal models and through in vitro laboratory research. For the most part, studies conducted on green and black tea, which are both from the Camellia sinensis plant, have yielded similar results. Recent research suggests that tea and tea flavonoids may play important roles in various areas of health and may operate through a number of different mechanisms still being explored.
As research continues, here are some exciting recent findings:
Human population studies have found that people who regularly consume three or more cups of Black Tea per day have a reduced risk of heart disease and stroke. The current body of research suggests that drinking tea can offer significant heart health benefits ranging from reducing heart attack risk to lowering Low Density Lipoprotein (LDL) cholesterol, or "bad" cholesterol, with benefits seen with just one cup and upwards of six cups a day. A Harvard study found that those who drank a cup or more of black tea per day had a 44% reduced risk of heart attack. In a large population based study, adults who drank just over two cups of green tea per day reduced their risk of death from cardiovascular disease by 22-23%. A US Department of Agriculture study found that participants who drank five cups of black tea per day along with a diet moderately low in fat and cholesterol reduced their LDL cholesterol by about 11% after three weeks. Additionally, a study published in the December 2013 issue of the American Journal of Clinical Nutrition found that black tea reduced blood pressure, and among hypertensive subjects, it helped counteract the negative effects of a high-fat meal on blood pressure and arterial blood flow.
More than 3,000 published research studies exist that evaluate the role tea-whether white, green, oolong or black-and tea compounds, such as epigallocatechin gallate (EGCG), may play in cancers of various sites. Benefits to gastrointestinal health reaped by tea-drinking seem to be cumulative and dependant upon the amount of tea consumed per day as well as the number of tea-drinking years. One study found that women who consumed the equivalent of 2.5 cups of tea per day had a 60% reduction in rectal cancer risk, compared with women who drank less than 1.2 cups of tea daily. An additional study found tea drinkers to have an approximate 42% reduced risk of colon cancer compared to non-tea drinkers. Men who drank more than 1.5 cups of tea per day were found to have a 70% lower colon cancer risk. One study showed that participants who drank iced black tea and citrus peel had a 42% reduced risk of skin cancer and hot black tea consumption was associated with a significantly lower risk of the most common form of skin cancer, squamous cell carcinoma. A study published in the February 2015 issue of the Journal of Molecular Nutrition and Food Research found that the main antioxidant in green tea, epigallocatechin-3-gallate (EGCG), helps kill cancer cells through the destruction of the cells' mitochondria.
Age-related declines in memory and cognition occur naturally, but research suggests that modifiable factors, such as diet and exercise, may help slow the progression of age-related neurodegeneration. Research indicates recommendations to improve heart and cardiovascular function are also neuroprotective. The benefits of tea that help improve biomarkers for reducing risk of heart disease may improve brain health too. The antioxidants in tea may be one way to help protect brain cells from environmental insults from free radicals. In addition, L-theanine in tea has been shown to directly affect areas of the brain that control attention and ability to solve complex problems. A recently published long-term study of nearly 30,000 adults found that drinking three or more cups of tea per day was associated with a 69% reduced risk of developing Parkinson's disease. According to research presented at the 2007 Scientific Symposium on Tea and Health, theanine, an amino acid that is for the most part uniquely found in tea (green and black), may help prevent age-related memory decline. This human-based data is supported by recent animal studies utilizing theanine. Another recent animal study shows that green tea may have protective effects against Alzheimer's disease.
Metabolism, Obesity and Body Composition:
Several studies suggest drinking calorie-free tea may help with weight management. Preliminary research suggests that tea flavonoids help elevate metabolic rate, increase fat oxidation and improve insulin activity. Tea catechins can also provide modest shifts in metabolism that may improve weight loss and maintenance. In one review, researchers concluded that subjects consuming green tea and caffeine lost an average of 2.9 pounds within 12 weeks while adhering to their regular diet. The results of another meta-analysis suggest the increase in caloric expenditure is equal to about 100 calories over a 24-hour period. The weight loss benefits of tea vary based on many factors, but studies have found benefits with the equivalent of as little as 2.5 cups of green tea.
Tea and Reduced Risk of Osteoporosis:
Although high caffeine intake has been suggested to be a risk factor for reduced bone mineral density (BMD), drinking tea has been linked to higher bone mineral density (BMD) and has been shown to boost bone-building markers and improve muscle mass, both of which may reduce the risk for osteoporosis and fracture. Compared to non-tea drinkers, tea drinkers have been found to have a higher BMD. Research suggests that polyphenols in green tea may help improve bone quality and strength. One study found that drinking tea was associated with a 30 percent reduced risk in hip fractures among men and women 50 years of age or older.