A apple a day keeps the doctor away.--where does this phrase originate from?

Apple Farmers of America .
Cha-ching.

Greedy doctors who want to convince you that simply eating an apple a day will keep your money away from their wallets.

One of the most popular quotations of the 19th Century was "An apple a day keeps the doctor away. Before the 20th century there was no food pyramid or someone to announce the importance of five servings of fruits and vegetables every day. People simply recognized the healthy attributes of the apple. Some people were also well aware of the apple's relationship to the history of the world. Author-naturalist Henry David Thoreau wrote, "It is remarkable how closely the history of the apple tree is connected with that of man."

This is the only reference to the adage I could find. Here is the site I found the info at if you would like to read the rest:

http://chetday.com/appleaday.htm

Seriously. You all think that this has to do with health? It originated from a small town that was being plagued by a serial killer.

He would come at night and murder people. So they started leaving apples out for him as an offering. Everytime they left an apple he'd spare the lives of the people.

Yeah. I saw it on NatGeo.

http://www.rhymes.org.uk/an_apple_a_day.htm

The origin is untraceable, which I believe.

It the early days of medicine, during the outbreaks of the black plague, it was thought that eating fresh fruit, along with sniffing possy flowers would render you imune from the black plague.