← Back to the front page

A Surgeon With 300% Mortality Rate From a Single Operation and Other Historic Screwups

Khalid Elhassan October 11, 2020 32 min

Robert Liston - Surgery — Dr. Robert Liston operating. Wellcome Images

6. Decimal Point Placement Mistake Turns Spinach Into a Super Food

The mistake that gave rise to the spinach-is-a-super-food myth. Weltmurksbude

Popeye’s passion for spinach, as well as the popular faith in its exceptional qualities, was caused by a simple mathematical mistake. In 1870, German scientist Erich von Wolf was conducting research into the amount of iron in spinach and other vegetables. He discovered that spinach had an iron content of 3.5 milligrams per 100-gram serving.

However, when Wolf wrote his findings, he misplaced a decimal point, putting down spinach’s iron content as ten times greater than what it actually was: 35 milligrams of iron per 100-gram serving, instead of 3.5 milligrams. It was not until 1937 that somebody double-checked Wolf’s math, and spotted the error. By then, Popeye was already a cultural icon, and the spinach myth had taken hold.

Written by

Khalid Elhassan

A lifelong history buff, I developed a particular passion for WW2 history as a child, when I spent hours listening to my grandfather, enraptured, as he recounted his wartime experiences in the British East African Campaign and with the British 8th Army in North Africa.

I graduated with a history BA from George Mason University, then went on to get a JD from the University of Virginia School of Law. After lawyering for a decade, I moved to sunny Rio de Janeiro and a less demanding career, opening a tourism agency in Copacabana.

A big chunk of my free time is spent blogging (you can follow me on Quora https://www.quora.com/profile/Khalid-Elhassan ) or freelance writing, mostly about my favorite subject, history.