Cup of tea?Many of us have great faith in the soothing and restoring powers of a nice cup of tea, but could the health benefits of our favourite tipple go even further? As part of a massive international research effort underway to try and understand more about tea, scientists at the Institute of Food Research on the Norwich Research Park have made their own contribution to increasing our knowledge about this age-old drink. For centuries, tea has been a cultural cornerstone of meals and celebrations for people in many Asian countries. And serving high quality (and sometimes very expensive!) green tea to your guests is still a symbol of status in China - a far cry from our less traditional habit of dunking a tea bag in a mug of hot water. But tea, and green tea in particular, is attracting the interest of scientists all over the world, as it seems to contain chemicals that help protect us against certain diseases. So researchers are trying to find out just what these chemicals are, and how they might help keep us healthy by combating the harmful things in our bodies. Some of the "bad guys" that cause problems in our bodies are free radicals; particularly dangerous are those formed spontaneously from reactions involving oxygen. As we breathe oxygen to live, we also generate lots of these highly reactive harmful by-products (free radicals) at the same time. Heart disease, ageing and cancer have all been attributed to the action of free radicals, so finding ways of "mopping them up" is thought to be one solution to staying healthy for longer. Although our bodies have inbuilt mechanisms to mop up free radicals, several foods contain chemicals, such as Vitamin E, that make this process more effective. And tea, particularly the green type, contains related chemicals known as polyphenols, which also help to destroy free radicals. The challenge is to identify these polyphenols and see how they work. The Institute of Food Research is one of the world centres for analysing the health-giving components of food. The expertise in free radical chemistry at IFR attracted a group from a Chinese laboratory who were working on green tea, and several of their scientists have been to IFR to work alongside the Norwich scientists. Armed with a traditional tea variety, one of their scientists worked at IFR for more than a year. During that time she studied the way that free radicals are mopped up by the polyphenols in a particular variety of green tea. In an attempt to provide conditions similar to those in the cells of our body, the scientists made tiny "spheres" out of synthetic cell membranes. To these spheres, they added some well-studied free radicals, then mixed them with the tea. The scientists were then able to detect whether the free radicals in the spheres had been destroyed by the polyphenols in the tea. There are four major polyphenols in green tea that destroy free radicals. Some of the polyphenols are more effective than others, but all seem to have a role to play in the health-giving properties of the tea. Sadly the funding for this project has finished but the work is continuing in China. The contribution made by IFR scientists in the collaboration with the Chinese group has hopefully put one more piece in the massive jigsaw that is our understanding of protective foods. © Dr Belinda Clarke 2003 This Article originally appeared as part of the "Science
on your Doorstep" series, published in the Eastern Daily Press
12th April 2003
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