Most grandparents that turn 80,90, or even hundred do so because of modern medicine and not because they are soo healthy. Did you ever ask your grandpa or grandma what medications she has taken in the last 10-20 years? Modern medicines does miracle work.

Another reason are dentures. Humans are able to chew properly much longer and therefore can eat certain food groups longer in life - helping to stronger and therefore live longer.

Oregonchick