I reckon most people know about this fact.
I had read one article (based on his thesis on the Jewish people and their lifestyle) by one Dr Stephen Carr Leon.
According to him, almost all of the time when he was invited to dine with a Jewish family -- fish is the main course.
And when their women are pregnant, fish and varieties of nuts would be her diet and snacks.
It's not an overstatement if I say that is why they are the brainy lots, would it?