Researchers have found that a mutation on the gene known as APOC3 appears to protect people from the heart-damaging effects of a fatty diet. In a recent study, scientists found that five percent of the people they examined--all of whom were Amish--had the relatively rare protective mutation, which appears to speed up the breakdown of triglycerides in the blood. Investigators say the Amish, who tend to be genetically similar because of their social segregation, sometimes have much higher or much...