So, this guy -----> http://www.youtube.com/watch?v=ff40YiMmVkU Dan Buettner gave a TED talk about people who have lived to be a healthy 100 or more. One of his arguments for this active longevity is the fact that the cultures, where these 100-year-olds come from, respect their elders. He attributes the care and compassion given to the elderly by the youth as one of the reasons why they live to be so old. This seems to make sense. However, there may be another reason behind the length of life other than the fact that the young people take care of the old people. Let me explain.
My grandmother is almost 90 years old now. She also drives herself around town just fine, goes grocery shopping, tends to her garden, and climbs the stairs to her second story bedroom several times a day; AND she has had TWO knee replacements. She is stubborn, and is always barking in the sweetest tone possible that she can do it herself. When I ask how she is still getting so well, she gladly replies that it was making sure she had vegetables as a main part of every meal and that she make an effort to keep herself moving.
Now, If she keeps it up another ten years or so, she might not only make it to 100, but she might also get to meet her first great-great-grandchild. So, thinking about what Buettner said, I don't really think the fact that the youth take care of the elderly effects the healthy longevity of the elderly. My grandmother lives completely alone and takes care of herself with no help at all. So, think for a minute how it would be like in a culture where she was highly respected for her age.
When the great-grandchildren are gathered around asking how to live to be as long and happy as she has, will the youth in that culture listen better than some teen visiting his gramps in hospice? I would hope so.
This sets up an almost social natural selection for longevity behaviors. The child who follows the advice and lifestyle of elderly would seem to have a better chance of making to to that healthy age. On the other hand, the children who shrug off listening to the elderly and snack on a big mac might find themselves riddled with western-world health problems like diabetes and heart disease.
So, wrapping all of this up, when it comes to long and healthy lives, it is not the fact that some youth may give a helping hand to the elderly, like Buettner suggests; it has more to do with the idea that the cultures that put a higher emphasis on respect for elders the older that they get are actually encouraging a social structure that naturally promotes long and healthy lives when the advice of the elderly is taken very seriously by the youth.