"We shall draw from the heart of suffering itself the means of inspiration and survival."
~ Winston Churchill
I remember reading some time ago about a study of longevity in humans. There has been a large body of scientific research into the reasons why some people are long-lived but of course while various diets, health regimes, and regional or ethnic differences are often linked to living long it is a very difficult cause and effect relationship to determine because there are so many other variables involved.