Since the time of Chinese Emperor Sheng Nong over 4,000 years ago, Asians have consumed the bitter brew created when tea leaves steep in hot water. One legend suggests that Emperor Nong discovered the brew accidentally while boiling water under a tea tree. An avid student of medicinal herbs, Nong wrote extensively about the health benefits of tea. Recent research has found benefits of great interest to an increasingly obese US population. Certain compounds called catechins in green tea assists with weight loss, particularly when paired with a program of regular exercise.
Catechins
Catechins are powerful antioxidants in green tea that neutralize free radicals, the molecules that damage cell walls and DNA by stealing electrons. Catechins protect the tea plant from the damaging effect of free radicals, but when you drink the catechins in green tea, they also protect you. Catechins, and other polyphenols in green tea, such as theanine, may lower the risk of Parkinson's disease, certain types of cancer, heart attacks and several neurological disorders. Catechins also appear to contribute to weight loss and fat metabolism.
Exercise Induced Weight Loss
Catechins contribute to loss of belly fat when consumed in conjunction with a regular program of moderately intense exercise. A recent study, examined the effects of catechins on overweight and obese participants in a 12-week exercise program. The study volunteers did 180 minutes of exercise a week. Half the participants drank a beverage that contained 625 mg of catechins and 39 mg of caffeine, while the other half drank a similar beverage that did not have the catechins or caffeine. After 12 weeks, those who consumed catechins daily had greater losses of subcutaneous fat and abdominal fat and had lower levels of triglycerides -- fatty acids that circulate in the blood.
Diet Booster
All teas have various kinds of catechins, but the type of catechin found in green tea, epigallocatechin gallate, or EGCg, is the most powerful of the antioxidants. EGCg increases production of heat in your body, which increases how many calories you burn. A 12-week study of obese, middle-aged men on a calorie-restricted diet randomly assigned half the dieters to drink green tea daily. This study, published in 2008 in "Physiology & Behavior" found that the tea drinkers lost 7.3 more pounds of weight than the non-tea drinkers. Examinations at four-week intervals indicated that the tea drinkers had increases in energy expenditure and fat metabolism.
Weight Loss
The catechins in green tea, assist with weight loss during exercise and diet. The catechins in tea may directly affect weight and fat loss even in the absence of intense exercise and a calorie-restricted diet. A 2005 study published in the January "American Journal of Clinical Nutrition" found that body mass index, waist circumference, body weight and subcutaneous fat were all lower in a group of obese Japanese men who drank tea with high amounts of green tea extracts. In this 12-week study, the men who consumed 690 mg of catechins each day also tended to have lower levels of modified LDL, a form of "bad" cholesterol that is associated with body mass index.
Limits
A typical cup of green tea contains about 127 mg of catechins. The amount of catechins used in these studies was equivalent to about 5 cups of tea, more than even avid tea lovers drink in a day. Studies that examine the effect of green tea and catechins on weight loss and fat metabolism tend to find statistically and clinically significant effects. Still, green tea is no magic bullet. Don't expect that you can drink green tea and eat with abandon. If you want to lose weight, drink green tea but more importantly, maintain a modest, calorie-wise diet and a regular program of moderately intense exercise.
References
- Amazing Green Tea; EGCG, Catechins and Polyphenols in Green Tea: A FAQ Guide
- "The American Journal of Clinical Nutrition"; Ingestion of a Tea Rich in Catechin Leads to Reductino in Body Fat and Malondialdehyde-modified LDL in Men; Romonori Nagao, et al; Jan. 2005
- "Physiology & Behavior"; Effectiveness of Green Tea; Paradee Auvichayapat, et al; February 2008
- Psychology Today; Green Tea on the Brain; Anne Becker; Oct. 2005
- "The Journal of Nutrition and Disease"; Green Tea Catechin Consumpton Enhances Exercise-Induced Abdominal Fat Loss in Overweight and Obese Adults; Kevin Maki, et al.; Dec. 2008
Member Comments