In 1870, A German Chemist Made An Error In Transcribing Data About How Much Iron Is In Spinach

He didn't live long enough to clear his name. One of the strangest examples of the spread of that error is related to Popeye the Sailor.

Popeye, with his odd accent and improbable forearms, used spinach to great effect, a sort of anti-Kryptonite. It gave him his strength, and perhaps his distinctive speaking style. But why did Popeye eat so much spinach? What was the reason for his obsession with such a strange food?

"The truth begins more than fifty years earlier. Back in 1870, Erich von Wolf, a German chemist, examined the amount of iron within spinach, among many other green vegetables. In recording his findings, von Wolf accidentally misplaced a decimal point when transcribing data from his notebook, changing the iron content in spinach by an order of magnitude. While there are actually only 3.5 milligrams of iron in a 100-gram serving of spinach, the accepted fact became 35 milligrams. To put this in perspective, if the calculation were correct each 100-gram service would be like eating a small piece of paper clip.

"Once this incorrect number was printed, spinach's nutritional value became legendary. So when Popeye was created, studio executives recommended he eat spinach for his strength, due to its vaunted health properties. Apparently Popeye helped increase American consumption of spinach by a third!

"This error was eventually corrected in 1937, when someone rechecked the numbers. But the damage had been done. It spread and spread, and only recently has gone by the wayside, no doubt helped by Popeye's relative obscurity today. But the error was so widespread that the British Medical Journal published an article discussing this spinach incident in 1981, trying its best to finally debunk the issue.

"Ultimately, the reason these types of errors spread is because it's a lot easier to spread the first thing you find, on the fact that sounds correct, than to delve deeply into the literature in search of the correct fact."

Author: Samuel Arbesman
Title: The Half-Life of Facts