A Chinese research study of laboratory animals, only recently reported on the web, confirmed a body of evidence already accumulated that green tea protects against cancer development at various organ sites. This study showed that green tea inhibits lung tumor development in mice that had been dosed with a potent nicotine-derived lung carcinogen found in tobacco. The inhibitory effect of green tea on lung cancer is attributed to its major polyphenolic compound, epigallocatechin gallate (EGCG), and, to a lesser extent, to caffeine. Of course, the contribution of the caffeine in green tea, which contains only a very small amount of caffeine, is probably much less than is afforded by coffee, which delivers at least 15 times the amount of caffeine found in green tea.
The study, “The Prevention of Lung Cancer Induced by a Tobacco-Specific Carcinogen in Rodents by Green and Black Tea,” was published in Proceedings of the Society for Experimental Biology and Medicine.
Fung-Lung Chung, leader of the study, stated, “The protective effect of tea and caffeine against lung cancer demonstrated in our animal studies provides some basis to warrant large scale, well designed epidemiological studies or intervention trials to further assess the role of tea and caffeine in lung cancer among smokers.”
It’s long been known that caffeine protects against the pulmonary complications of smoking. This research confirms that caffeine exerts substantial protection against tobacco-tar induced tumors in mice, in other words, protection against lung cancer caused by smoking cigarettes.
How does this protection work? Semiquinone, a long-lived free radical in tobacco tar, reacts with oxygen to generate ROS (reactive oxygen species), chemically reactive molecules containing oxygen, which induce the development of lung cancer. In smokers who also drink coffee, the ROS is removed and, therefore, the incidence of tumor formation is reduced. This same mechanism is thought to underlie the protection against lung cancer afforded by green tea.
If this explanation is correct, then it may be that caffeine’s power as an extremely strong anti-oxidant is the key to how caffeine affords protection against lung cancer.
It seems that this study gives us yet another reason to support research into developing caffeine as a drug to combat serious illness!