Of all the controversial claims about green teas health benefits, the one that draws the most scepticism is the claim that it could be a cure for cancer. While it is almost certainly not a cure, however, many studies appear to show that lifelong green tea drinking does in fact reduce the risk of cancer in later life.

The biggest piece of evidence in support of this theory is known as the Asian paradox. The Asian paradox, according to researchers at Yale, is that Asia has very high levels of cigarette smoking, yet lower cancer rates than Europe or America. The researchers believe that the difference between the places lies in the Asians consumption of large amounts of green tea (over a litre a day on average).

Other studies have supported this view: one study comparing elderly Japanese people who drank green tea with ones who didnt found that the green tea drinkers tended to live a few years longer. Studies at Murcia University in Spain found that a chemical in green tea called EGCG is very similar to the cancer drug methotrexate, in that it appears to kill cancer cells in the same way. This is some of the most encouraging research yet, as methotrexate is a drug with many unpleasant side effects, and replacing it with green tea could work very well.

However, the unfortunate counterpoint to all this is that very large quantities of green tea have actually been found to cause cancer in lab rats, suggesting that too much green tea can be worse for you than none at all perhaps a similar effect to the one red wine has. The state of the research overall is inconclusive, as few drug companies are interested in funding studies into something that is seen as alternative medicine, the testing is left to interested but under-funded universities. Hopefully, over the next few decades, there will be more interest in investigating the health benefits of green tea, and we will finally get our answer.