A new margarine made with a fat-blocking derivative from pine trees lowers blood cholesterol by an average of 14 per cent in people who eat it, US researchers reported on Wednesday. Men and women with borderline-high cholesterol who are the spread regularly lowered both their total chloesterol and their so-called 'bad' LDL cholesterol, which logs up arteries.The spread, sold under the name Benecol in Finland, will be launched in the US later this year.