Why do some people live longer than others?

For a growing number of Americans, 100 is the new 80. There are about 84,000 centenarians living in the United States, a number that is expected to increase 10 times by the year 2050, according to the U.S. Census Bureau. The secrets of longevity have been a source of fascination for millenniums. Over the course of human history, numerous diets, lifestyle regimens and supplements have been touted.