Back in March one of my blog posts focused on the effects of green tea constituents known as catechins had on the metabolism of fat in the body. A recent study has found that green tea catechins stimulated fat-burning in the body, something which is an obvious boon to individuals seeking to attain or maintain a healthy weight. This study came on the back of other evidence which suggests that catechins can indeed promote fat loss in the human body [1].
Further evidence for the weight loss promoting effects of catechins has come in the form of another study published recently in the Journal of Nutrition [2]. In this study, 107 individuals were given a daily beverage containing 625 mg of catechins or a drink containing no catechins for a period of 12 weeks. 625 mg of catechins is amount to be found in the equivalent of about 5 cups of green tea. Both drinks also contained identical amounts (39 mg) of caffeine.
Over the 12-week study period, individuals were advised to partake in three hours or more of moderate intensity activity each week. 3 or more exercise sessions were supervised.
At the beginning and end of the study, participants underwent a variety of measurements including body composition and the ‘abdominal fat area’ (a measure of amount of fat in and around the abdomen). Higher abdominal fat area readings are a concern because it is fat in this region of the body that is most strongly correlated with an increase in risk of chronic diseases such as type 2 diabetes and heart disease.
The results of this study found that changes in overall fat levels (fat mass) in the body were not different between the two groups. However, fat area in the abdomen was significantly lower in the group consuming the catechin-laced beverage. As an added bonus, levels of blood fats known as triglycerides were significantly lower the catechin-consuming group too. This is good news because raised triglyeride levels are associated with an increased risk of heart disease.
Taken as a whole, this and previous research suggests that catechins derived from green tea may boost the body’s metabolism of fat, particularly abdominal fat. It might also be borne in mind that other research has linked green tea with potential protection from conditions such as cardiovascular disease and breast cancer.
A word of caution though: a recently published study found evidence that green tea components appear to block the action of the chemotherapy drug bortezomib (Velcade) [4]. Those taking this drug should consult their doctors regarding green tea use.
References:
1. Nagao T, et al. Ingestion of a tea rich in catechins leads to a reduction in body fat and malondialdehyde-modified LDL in men. American Journal of Clinical Nutrition 2005;81(1):122-129
2. Maki KC, et al. Green Tea Catechin Consumption Enhances Exercise-Induced Abdominal Fat Loss in Overweight and Obese Adults. J Nutr 2009 139: 264-270.
3. Khokhar S, et al. Total phenol, catechin, and caffeine contents of teas commonly consumed in the United Kingdom. J Agric Food Chem. 2002;50(3):565-70.
4. Golden EB, et al. Green tea polyphenols block the anticancer effects of bortezomib and other boronic acid-based proteasome inhibitors. Blood. 2009 Feb 3. [Epub ahead of print]
Thanks for another good nugget Doc. It’s always good to have more evidence supporting common practice.
Cheers,
Adam
The study participants were given 625mg of catechins as one daily dose. Is there a difference if the dose of catechins was spread out through the day. My green tea capsules contain only 100mg catechins per capsule, so need to take about 6.
Thanks, Doc. It was my impression that Green Tea was helpful, but I appreciate the solid information backing me up. With help from this and a couple of other blogs, my eating habits are getting better and better, but my system is so messed up from all those years of chowing down on “healthy whole grains” that I’ll take any help I can get on the way back to healthy.
Add a dash of lemon, lime or other citrus juice to your green tea — which protects the beneficial ingredients as they make their way through your digestive system and multiplies the positive effect.
There is a lot of research on this subject. Here is a link to a news article summarizing sources: http://www.thaindian.com/newsportal/health1/a-dash-of-lemon-in-your-green-tea-may-boost-its-antioxidant-levels_1004952.html
And it tastes good!
Could this be achieved by drinking green tea (how much per day?) or do you need to take supplements?
I didn’t know you could get green tea capsules – this is great news, because I find the stuff undrinkable. Is it just as good to take it in pill form? And going back to Sue’s question, do the capsules exist in one daily dose form? Thanks!
Interesting. The emerging knowledge about the constituent phyto-nutrients in herbs and food is exciting and the growing understanding is some of the more helpful science to reach ordinary people. Even considering food in the context of satisfying hunger and purely on the basis of eating to meet energy requirements it supports many complex metabolic and regulatorary functions, does it not? Evolution has shaped the inner workings of our bodies in that way.
Nature has also provided much vegetable matter that is inedible for humans, or even significantly toxic.
Just as the pharmaceutical industry is busy beavering away concocting the next wonder-drug there are individuals with a scepticism for pharmaceuticals who would like to latch on to some wonder herb. A cure without side-effects.
When Doctors prescribe a drug for a condition or in a way that has not been fully researched does not the term “going off-label” apply? It acknowledges that despite aspirations for benefits there are greater risks for complications than in licensed application.
I like green tea, it seems it has powerful anti-oxidant constituents. I can drink it without sugar and I don’t mind it hot, cold, or in between. It has negligable glycemic load.
However, I am minded to think quite cautiously. Do we fully understand the potential potency of constituents even within wholly natural foods and herbs and do we fully understand how nature dictates that the complex workings of our bodies make use of them. In a metaphor, my purely personal point of view would be to caution “going off-label” in relation to nature. I would not naturally assume that natural remedies or supplements, when taken in doses that nature has not prepared our bodies for, are entirely without unforeseen consequences. Research is just as important as with pharmaceuticals.
(Anything that could help me lose a little weight from around my middle would be helpful!)
I finally got around to thumbing the pages of New Scientist (14/02/09 issue) and In Brief reports of the drug interaction you mention in your final paragraph.
The team led by Axel Schonthal of the University of Southern California established that in mice ECGC, an antioxidant constituent of green tea, blocked the efficacy of bortezomib to shrink cancer tumours.