EGCG was also tested on tamoxifen, a drug used to treat breast cancer, and the compound was found to be twice as effective in killing the cells than the drug alone. In both cases the combined medication also reduced the risk of side effects. Research at Oregon State University, showed that drinking green and black tea inhibited the development of pre-cancerous lesions in the colons of rats. Other studies suggest similar effects in oesophageal and stomach cancer. Three or four cups per day, with milk, provides 16 per cent of the UK recommended intake of calcium, a tenth of our folic acid needs and a quarter of the vitamin B2 requirement.
Tea is also one of the few natural dietary sources of fluoride which strengthens teeth.
Research at Newcastle University suggested three cups a day can help prevent tooth decay in children. In 1993, a Lancet report showed people with the highest intake of the anti-oxidant flavonoid had less than half the risk of dying of coronary heart disease than people with the lowest consumption. And a Dutch study suggested drinking five cups a day could cut the risk of suffering a stroke by up to 70 per cent. The results of a recent Australian Government research project indicated that mice drinking green tea experienced an average reduction of 18 per cent in skin cancer, while those drinking black tea showed a reduction of 54 per cent. Tea drinking increases concentration and the ability to learn, according to research by Kimron Shapiro, a professor of psychology at the University of Wales.