How can we help our senior citizens to be Healthy?

Well you can start by treating them as individuals, that have individual needs, and not just lumping them together.

Talk to senior citizens as if they are your equals and not with some "feel sorry for you" voice.
And when a senior citizens has reached an old age and still is alive - let them live the way they want to.
Maybe life is nicer with a few "sins" even if it is shorter than a life with all kinds of no no and no sinning but with a lot of boordom.