The St. Petersburg Times investigates centenarian and other longevity studies: "By analyzing why the super-old age so well, scientists are gaining valuable information about avoiding the cancers, strokes and heart diseases that ravage younger people and cut short their lives." It turns out to have as much to do with diet and lifestyle as genes - you have a great deal of control over how much damage you are doing to yourself over the years. Since we are talking about diet, calorie restriction should get a mention - it is the only currently proven method of even slightly extending the healthy human life span. For far longer, healthier lives, we must support the future of medical research.
Link: http://www.sptimes.com/2004/08/31/State/Keys_to_long_life_see.shtml