I was going to leave a two word response but see you already covered it. Olive oil. ; )
When my late wife asked our 90 year old neighbor what the secret to her longevity was, we got a shocking answer, “I tried never to do anything to help other people, and only did things for myself” was her answer. Needless to say, it was something of a shock to hear her say that her long life was due to her selfishness.
Funny, 8 years later, she is still alive, but my wife has been dead for 4 years, and died at 39.
Maybe she is on to something.