Researchers have added to evidence that green tea, widely drunk in the SAR, may help lower cholesterol. Antioxidants are the key to the way green tea clears cholesterol from the blood, according to the Commonwealth Scientific and Industrial Research Organisation in Australia. Cholesterol can cause heart disease. Scientists carried out a study on rabbits and found a type of antioxidant - cathechin - is highly concentrated in green tea. This substance increases the amount of a liver protein that controls cholesterol. In Hong Kong, green-tea drinkers may have been controlling their cholesterol without knowing it. 'One of the things about the Asian diet is that it creates low cholesterol, and this is one part of the Asian diet we've found that is a factor,' said Dr Paul Roach, the organisation's senior research scientist. Statistics show that Hong Kong imported 3.24 million kilograms of green tea last year. There are more than 300 tea trading companies in the SAR. Dr Roach said black tea contained cathechins, but at much lower levels, as they are oxidised during processing. The organisation's research confirms earlier studies that found a connection between drinking tea and lower cholesterol, but Dr Roach said it was the first study to conclusively prove why the reaction happened. Previous studies suggested that by drinking five to 10 cups of green tea a day, people could lower cholesterol by up to 10 per cent. Dr Roach said the next step was to test the effectiveness of green tea extract in humans against the tea itself. 'It might be better than drinking the tea itself,' he said. He said that in addition to cholesterol-lowering antioxidants, green tea contained a small amount of caffeine. Regardless of whether this caffeine was harmful, it would not stop the tea from keeping cholesterol levels low.