Scientists Make Sweet Discovery Good news for chocoholics：the treat preferred by millions all over the world is good for you，according to American researchers at the University of California．Chocolate contains substances called fla vonoids(类黄酮)that can help maintain a healthy heart and good circulation．The researchers have discovered that cocoa acts like aspirin and that eating a bar of chocolate once in a while may contribute to a healthy diet．Chocolate has also been shown to release endorphins(内啡肽)in the body：these chemicals help to reduce pain and stress and make you feel happy． But who first discovered this wonderful way of keeping healthy?The Olmec Indians of Mexico and Central America were the first to grow cocoa beans，in about 1500 BC．and the Mayas were drinking un sweetened cocoa hundreds of years before it became fashionable in Europe．The word chocolate comes from the Nahuatl word xocolati，which means“bitter water”． In 1544，a delegation of Mayan nobles visited Philip of Spain and gave him jars of cocoa as a gift．Cocoa soon became fashionable in Spain and Portugal．The Spanish were the first to add sugar to their Cocoa drink．In the 17th century，chocolate was becoming fashionable with the middle-classes，not only as a drink but also as a medicine． By the middle of the century，solid chocolate was becoming familiar．In 1753，a Swedish scientist renamed cocoa theobroma or“food for the gods”．In 1765，James Baker and John Hanan opened the first chocolate mill in the United States，introducing chocolate to the average citizen．In 1876，in Switzerland， Daniel Peter had the idea of adding milk in the chocolate． process and produced the first milk chocolate． Since then，chocolate has grown enormously in popularity．One of the biggest chocolate-eating nations is Britain where the average man，woman，and child eats nine kilos of chocolate a year!In fact，chocolate is the number one comfort food and there are more“chocoholics”in Britain than anywhere else in the world． Researchers warn that although chocolate is good for you，it should be eaten in small quantities-and with no added milk． Why is chocolate good for heart and circulation?