In 1870 Erich Wolff was studying the iron content in different foods and mismeasured the iron content in spinach. (There's a legend about a misplaced decimal point that seems to be a myth, but his research did lead to incorrectly high scores for spinach and other vegetables.)

Then a few decades later, the newspaper strip Thimble Theatre became a big hit because of a side character, a sailor named Popeye. Popeye could gain tremendous strength by... rubbing a magic chicken.