What are the benefits of drinking Green Tea?

The main beneficial ingredient in green tea is flavanoids, a plant derived compound that is an antioxidant and epigallocatechin-3-gallate (EGCG).  

The benefits it offers you as a regular drinker are:

• Reduce the risk of cancer (such as skin, breast, lung, colon, esophageal, and bladder cancers) 
• Reduce bad cholesterol, and improve good cholesterol
• Improve artery function and reduce risk of heart disease / hypertension
• Improve glucose tolerance and insulin tolerance – could help diabetics
• Improve cognitive function
• Help treat skin disorders
• (Boosts metabolism and aids weight loss)

Where is the proof though, it is easy to make wild claims, and create a new food fad! Here is the proof, all good sound research that supports most of the claims made above.

There is some doubt over the weight loss claim, so I put it at the foot of the article, and explained what I found.

1.      Reduce the risk of cancer (such as skin, breast, lung, colon, esophageal, and bladder cancers)

There is very strong research by Fujiki et al (2003) on green tea as a cancer preventer to support the fact that green tea is a very effective way to prevent, or delay the onset of cancer symptoms. Nakachi’s research (2008) into the effects of drinking green tea on cancer and cardiovascular disease  also supports this conclusion. In studies by Suganuma et al (2000) is has been shown that green tea is the most effective beverage for cancer prevention in humans.

2.      Reduce bad cholesterol, and improve good cholesterol

Maron et al (2003) have completed research which concludes that  there is in fact a positive effect that supports the statement that there are Cholesterol-Lowering Effect in Green Tea.

3.      Improve artery function and reduce risk of heart disease /hypertension

Nakachi’s research (2008) into the effects of green tea on cancer and cardio vascular disease also strongly suggests that green tea can also help reduce heart disease.

4.      Improve glucose tolerance and insulin tolerance – could help diabetics

The research by Walter-Law et al (2002) on green tea’s effects on glucose production seems to conclusively prove that it is in fact an effective treatment for diabetics.

5.      Improve cognitive function

Kuriyama (2006) researched green tea consumption and cognitive function. Hyung-Kym et al also researched this topic. The research proved that cognitive function was improved by green tea, and Hyung-Kim also suggested that it would be beneficial in the treatment of Alzheimer’s disease.  

6.      Help treat skin disorders

Katiyar conducted some research into skin photoprotection and links with green tea. The epigallocatechin-3-gallate (EGCG) found in Green tea has been found to be a good treatment for photoaging and melanoma, for example.   

CONFLICTING RESEARCH

·        Boosts metabolism and aids weight loss

I found two research articles, both by Diepvens et al (2005) as well as a study on overweight females. that suggest that this is in fact not true. conducted research that did not show any beneficial effects of green tea.  When I read the methods of the trial, I understand that the green tea was part of a low energy diet, therefore, I would need access to the whole article to investigate whether the effect of this diet on food consumption and desire was in fact a variable that was or was not considered. The women could have in fact just eaten slightly more, while still drinking green tea. It is hard to say when I can only get access to the abstract.

Berube-Parent published an article in the British Journal of Nutrition (2005) investigating the metabolic effects of green tea. He concluded that it does have some effect, however was unable to isolate effects of different dose levels.

Westerterp-Plantenga (2005) conducted research to find out if green tea helped with weight loss. It was reported as a result of this research, that green tea did in fact help. The research was conducted on obese people, and again linked with a low energy diet. Therefore again, I would need to know if the subjects ate more as a result of feeling more hungry, or was this variable managed effectively?

It seems research has not yet been able to nail down whether green tea alone can increase the body’s ability to metabolise fat. Dullo (1999) offers the following explanation:

‘Green tea has thermogenic properties and promotes fat oxidation beyond that explained by its caffeine content per se. The green tea extract may play a role in the control of body composition via sympathetic activation of thermogenesis, fat oxidation, or both.’

 It seems research has found that green tea COULD improve fat metabolism but as yet, I am unable to find some reliable research that is able to identify WHY, and what properties within the tea are responsible for this.

If you know of any, please feel free to contact me with the details and I will take a look at it.