Green Tea May Lower Total and LDL Cholesterol

Adapted from Nutrition Science News,  October, 1999

There is research indicating that drinking green tea lowers total cholesterol levels, as well as improving the ratio of good (HDL) cholesterol to bad (LDL) cholesterol.
 
The secret of green tea lies in the fact it is rich in catechin polyphenols, particularly epigallocatechin gallate (EGCG). EGCG is a powerful anti-oxidant: besides inhibiting the growth of cancer cells, it kills cancer cells without harming healthy tissue. It has also been effective in lowering LDL cholesterol levels, and inhibiting the abnormal formation of blood clots. The latter takes on added importance when you consider that thrombosis (the formation of abnormal blood clots) is the leading cause of heart attacks and stroke.
 
Links are being made between the effects of drinking green tea and the what is called the "French Paradox." For years, researchers were puzzled by the fact that, despite consuming a diet rich in fat, the French have a lower incidence of heart disease than Americans. The answer was found to lie in red wine, which contains resveratrol, a polyphenol that limits the negative effects of smoking and a fatty diet. In a 1997 study, researchers from the University of Kansas determined that EGCG is twice as powerful as resveratrol, which may explain why the rate of heart disease among Japanese men is quite low, even though approximately seventy-five percent are smokers.
 
Why don't other Chinese teas have similar health-giving properties? Green, oolong, and black teas all come from the leaves of the Camellia sinensis plant. What sets green tea apart is the way it is processed. Green tea leaves are steamed, which prevents the EGCG compound from being oxidized. By contrast, black and oolong tea leaves are made from fermented leaves, which results in the EGCG being converted into other compounds that are not nearly as effective in preventing and fighting various diseases.
 
Recent studies from Chinese researchers have demonstrated that certain chemicals in green tea lower cholesterol in animals - some researcher now think they have figured out how they work.
 
Ping Tim Chan and colleagues at the Chinese University of Hong Kong fed hamsters a high fat diet to raise their triglyceride and cholesterol levels to those of humans. They then fed the hamsters differing levels of epicatechins extracted from jasmine green tea for four to five weeks and compared them with hamsters that drank green tea and a control group that had water.
 
Epicatechins and green tea had exactly the same effect: Both lowered blood levels of triglycerides and cholesterol more than water. The effective doses researchers used are comparable to a person drinking three daily cups of tea. Animals drinking the human equivalent of 15 cups a day lowered both triglycerides and total cholesterol by a third.
 
Epicatechins and green tea also lowered apoB, the main protein in harmful low density lipoprotein (LDL), by almost a half. ApoB levels predict heart disease more accurately than any cholesterol measure.
 
According to the researchers, epicatechins block cholesterol absorption and increase excretion of cholesterol-containing bile salts and fatty acids. The chemicals also speed the breakdown of triglycerides to fatty acids so they can be burned as energy. Other studies show that in addition to their effect on blood fats, epicatechins are powerful antioxidants that lower blood pressure and protect against cancer.