Green tea health news: behind green tea's faint color and mild taste, lie powerful health benefits

As the weather cools and flu and cold season kicks into high gear, many people will turn to green tea as a natural method of relief. Due to recent findings regarding its health benefits, this beverage's popularity has reached an all-time high. Now, more than 15 million Americans are drinking green tea, with sales up 650 percent from 2002.

STRONGEST ANTIOXIDANT FOUND IN GREEN TEA

In September 1997, a study by Dr. Lester Mitscher, medicinal chemistry professor at the University of Kansas, concluded that green tea contains high concentrations of epigallocatechin gallate (EGCG), the strongest antioxidant. EGCG is over 100 times more effective in neutralizing free radicals than vitamin C and 25 times more powerful than vitamin E, both well-known antioxidants. EGCG also topped other antioxidants, such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and resveratol. Antioxidants are thought to prevent cellular damage that leads to certain diseases--especially cancer.

When compared to black and oolong tea, Mitscher indicated green tea contained, by far, the highest active EGCG concentrations. This is because green tea is steamed immediately after it is picked, which prevents the leaves from oxidizing, thus preserving EGCG. Although the daily green tea consumption needed to experience the antioxidant effect has not been established, Mitscher referred to previous studies conducted in China and Japan, which revealed a low incidence of degenerative disease. People in these countries customarily drink four or more cups of green tea per day.

ENHANCED WEIGHT LOSS

Two studies have proposed drinking green tea may help you lose weight. The first study compared green tea's metabolic effect, in extract, to that of a placebo. Researchers found green tea drinkers burned an additional 70 calories per day. The difference is believed to be caused by the catechins (i.e., antioxidants which enhance metabolism) in green tea. The second study, done by the University of Geneva, revealed combining caffeine and EGCG enhanced metabolic rate by 4 percent.

STRONGER BONES

A study by researchers from National Cheng Kung University Hospital in Tainan, Taiwan, suggested drinking tea may strengthen bones. Tea contains fluoride and flavonoids, both of which may enhance bone strength. The study was based on 1,037 men and women, ages 30 and older, who were questioned about their tea consumption habits and given bone-mineral density tests.

Researchers found the benefits were most noticeable in people who drank at least two cups of tea per day, for at least six years. People who habitually consumed tea for over 10 years had the highest overall bone mineral densities--6.2 percent higher than non-habitual tea drinkers. Habitual tea drinkers for six to 10 years had bone mineral densities that were 2.3 percent higher than non-habitual tea drinkers. No significant differences between tea drinkers of one to five years and non-habitual tea drinkers were established.

REDUCED CIGARETTE SMOKING EFFECTS

Two studies, one by scientists at the Academy of Preventive Medicine in Beijing, China, and the other by James Klaunig at the Indiana University School of Medicine in Indianapolis, investigated green tea's effects on oxidative stress (i.e., an imbalance in the pro-oxidant/antioxidant status of a cell) due to cigarette smoke toxins. Oxidative stress appears to cause or be a factor in the development of certain diseases--notably cancer. When smokers drank an equivalent of six cups of green tea per day, their bodies suffered 40 to 50 percent less oxidative damage. This potentially lowers their risk of cancer, emphysema, heart disease and other illnesses. However, it is important to note that those who drink green tea and continue to smoke continue to raise their oxidative damage risk. In addition, nonsmokers also exhibited significant oxidative damage decreases.

ORAL CANCER PREVENTION

At a 1998 symposium in Washington, D.C., Ning Li from the Institute of Nutrition and Food Hygiene, Zheng Sun from the Chinese Academy of Preventive Medicine and Junshi Chen from the Beijing Dental Hospital revealed drinking green tea improves pre-cancerous conditions of oral leukoplakia and suggested it may have certain preventive effects on oral cancer.

The study involved 32 patients, 20 males and 12 females, 23 to 28 years of age with oral mucosa leukoplakia (i.e., a pre-cancerous lesion of oral cancer). During a six-month period, patients drank three cups of green tea per day and applied a green tea and glycerin mixture directly to the lesion. As a result, 38 percent of the patients experienced a reduction in the size of a single lesion or total size of multiple lesions by 30 percent or more. Although 59 percent didn't experience any changes in size, cancerous cell formation rate decreased significantly. While this study's sample size and treatment duration were limited, the results provide encouraging and direct evidence of green tea's preventive effects on human cancer.