GREEN TEA: FACT SHEET

GREEN TEA: FACT SHEET
Prepared by Dr D. Carey—Endocrinologist and Weight loss Specialist (not for publication)
Health+ Diabetes Centre, Spring Hill, Brisbane


Active ingredient: Epigallocatechin gallate (EGCG)
•    a type of catechin.
•    abundant in tea,
•    potent antioxidant

Is it proven to Treat : BP , Cholesterol or  Heart disease - NO
•    Long term Green tea intake associated with reduced risk of Hypertension in one study of Chinese
•    But INTAKE:  tea 6 cups/day for 4 weeks

• NO EFFECT ON: cholesterol  and blood pressure  in controlled trials (31,32,36, 37 )
• Neither black nor green tea affected
• serum cholesterol
• or blood pressure.
• No evidence that it can reduce heart disease in humans

Can it enhance weight loss – Yes
Can it give clinically useful weight loss more than a high protein low fat diet– No
Green tea (epigallocatechin gallate + caffeine)

Metanalysis:  11/49 studies.
Asians  =-1.31 kg; P<0.001). I
Caucasian  = -0.82 kg subjects
Conclusions: Catechins or an epigallocatechin gallate (EGCG)-caffeine mixture have a small positive effect (which was statistically significant) . Catechins may decreased body weight and maintain body weight after a period of weight loss

DOSE: Suggested 5 cups per day:
COST EFFECTIVENESS: Estimated cost $1.20/day   or approx $440 per year
Cost per kg loss $400/kg approx 4x more expensive per kg loss than Reductil (prescribed weight loss drug)
A cup of green tea typically contains about 50 milligrams of caffeine (equivalent to about a half-cup of coffee). Green tea extracts that contain high levels of caffeine ( up to 7 cups of coffee)may also produce a diuretic effect- potentially resulting in a temporary loss of water weight.

SAFETY: Can it do any harm?
Can cause liver damage. One case of liver transplant required after using green tea extract. Best avoided if abnormal liver function.
Note: dangers of associated caffeine intake also need to be considered in people with heart disease.

References:
1    Int J Obes (Lond). 2009 Jul 14. The effects of green tea on weight loss and weight maintenance: a meta-analysis. Hursel R, Viechtbauer W, Westerterp-Plantenga MS.
2    Am J Clin Nutr. 2009 Mar;89(3):822-30. Epub 2009 Jan 28.    Green tea catechin plus caffeine supplementation to a high-protein diet has no additional effect on body weight maintenance after weight loss.Hursel R, Westerterp-Plantenga MS.
3    Eur J Gastroenterol Hepatol. 2005 Oct;17(10):1135-7.Fulminant hepatitis during self-medication with hydroalcoholic extract of green tea.