Can Tea Help to Prevent Cancer?

Tea has long been held to have medicinal benefits among Asian and Indian communities. As far back as the 12th century, it was being written about in the “Book of Tea”. This work, by a Zen master, describes how tea was believed to influence some of the major organs in the body, perhaps most importantly the heart. Green tea was also commonly drank to promote healthy urinary function, to cure indigestion and beriberi, and even to improve the functioning of the brain. Tea was considered to be a universal health drink that could treat many diverse symptoms.

Tea drinkers today can turn to more scientific evidence to validate the health benefits they may be getting from their green tea. There have been numerous attempts to substantiate the traditional medicinal role of tea, although the work from the lab has not yet been mirrored by the results from human trials. The most interesting finding, above the potential impact of green tea on cholesterol levels and mood disorders, is the discovery of a possible activity against cancer.

Cancer is caused by genetic mutations which affect the controls that normally regulate cell growth and division. If there are mutations in enough of these regulatory genes, then there will no longer be limitations on the division of affected cells. They will multiply uncontrollably.

Experiments in mice have discovered a beneficial effect on the size of tumors in many parts of the body, including cancers of the skin, liver and stomach, which have been found to shrink when the animals are given tea. This can either be in a solution of water or as its direct pure form. Green tea has even been demonstrated to have a beneficial effect on unborn mice exposed to it through their mothers.

Preventative powers have also been attributed to tea, which could be important for medicine due to the large numbers of regular tea drinkers, and the ease with which tea can be bought. There are around thirty tea producing nations, and many more that import tea from them. Tea is considered to be the most commonly drunk beverage around the world. The preventative ability of tea is again thought to work against many forms of cancer. This includes lung and breast cancer, as well as various cancers of the digestive system.

The reason why tea should have this effect on cancer development is as yet unclear. One theory involves the antioxidant catechins which it contains. Antioxidants are believed to reduce the damage which is done to DNA by oxidants that are produced through enzymatic activity in the body. Green tea, especially, is known to contain high levels of catechins. According to initial laboratory tests, these antioxidants could be preventing the damage that causes cancer, reducing tumor growth and making tumors less likely to develop.

The antioxidant theory of cancer prevention is currently the most popular. Studies into antioxidant activity have been conducted in many labs. While the evidence is clear that antioxidants can help prevent damage to cells, and that tea contains antioxidants, evidence that incontrovertibly links the antioxidants in tea with an activity in the body of the tea consumer that prevents gene damage has not as yet been forthcoming.

Despite the encouraging evidence that has so far been gathered, there is as yet little proof of a role in cancer prevention for human tea drinkers. Conflicting results have been found by different studies. It may be that the uncontrollably varying environmental factors such as diet and chemicals in the home could be masking the effect of green tea by causing wide variation between human trial participants in their exposure to cancer-causing factors in their everyday lives. A large study in the Netherlands, for instance, found no evidence of a link between tea and cancer prevention. In China, however, researchers found that men who drank tea had a significantly reduced rate of stomach cancers when compared with those who did not take tea.

Since the evidence is currently so inconclusive, the FDA does not support the claim that drinking tea can have any beneficial effects in reducing cancer or in preventing heart disease. A similar position is adopted by many governmental bodies and academics, but the debate still continues in scientific circles. Some researchers have directly attacked the FDA’s position, stating that they found an important reduction in fatal heart conditions in those who regularly drank at least three cups of green tea a day. The search for a medicinal effect of tea continues, with the possibility of a treatment in the form of pills or a cream containing green tea being investigated now.