Seems the misplaced decimal point theory was a myth (
see here) and the guy who invented Popeye wanted him to eat spinach for its Vitamin A quantity instead:
"The cartoon character came to life in 1929, soon after demand for canned vegetables skyrocketed after WWI, so it was only fitting that Popeye would promote a safe and inexpensive health food in that era. However, the cartoon strip published by Segar on July 3, 1932, attributed Popeye’s strength to the Vitamin A content in spinach and not iron. Segar’s intention was to increase the health of children by increasing
vitamin intake, not iron intake, from spinach." (
see here)