“What food is good for the brain?”/“Noodle soup.”

“Noodle” is slang for “brain.” A popular riddle is:
 
Q: What food is good for the brain?
A: Noodle soup.
 
The joke has been cited in print since at least 1976.
 
     
Google Books
Biggest Riddle Book in the World
By Joseph Rosenbloom
Illustrations by Joyce Behr
New York, NY: Sterling Publishing Company, Inc.
1976
Pg. 30:
What food is good for the brain?
Noodle soup.
 
10 October 1992, St. Louis (MO) Post-Dispatch, “Jumble,” pg. 9D, col. 2:
He ate plenty of noodle soup because he thought it was this—GOOD FOR HIS BRAIN
   
11 February 2007, Sunday Mail (Glasgow, Scotland), “Funnies,” pg. 3:
What food is good for the brain?
Noodle soup.
 
25 February 2009, Arizona Daily Star (Tucson, AZ), “Jokes corny enough to win readers cookbooks” by Kathleen Allen, pg. C3:
And this from Patricia Suhocki: “What food is good for the brain? Noodle soup.”
 
Twitter
Jamie Brook
‏@jbrook
Joke - Food jokes: What food is good for the brain? Noodle soup. http://76k.com/j/s20eox
6:35 PM - 7 Jan 2010
 
Living, Learning and Lovin’ Life!
What food is good for the brain? Noodle soup.
June 18, 2013 by Sam Smith
 
Google Books
Sensible Nonsense.. Frank’s Comic Pack:
Humour Pack Series
By Frank Paul
BookBaby
2014
Pg. ?:
What food is good for the brain?Noodle soup.