SPINACH AND IRON: A TALE OF TWO MYTHS

1850-2024

Most people have heard that spinach is a healthy vegetable because it’s loaded with iron. Some of us have also heard that the iron content of spinach is grossly overestimated due to a misplaced decimal point in an old nutrition study. But very few people know that the story about the decimal error is also a myth.

The story about the decimal error achieved international cult status in 1981, when haematologist Terry Hamblin wrote a short editorial about it in the British Medical Journal. He pointed out that the mistake was made in a 1890 study, and found in 1930 by German scientists. Nevertheless, the myth about iron-rich spinach stuck, thanks to Popeye, the famous cartoon hero who eats spinach to achieve superhuman strength.

But more recent historic research shows a different picture. The legend of spinach as a rich source of iron was already circulating in the 1860s - more than thirty years before the decimal error. Furthermore, there is no clear evidence that there has been a decimal error at all, and the overestimation is more likely the result of methodological errors and a mix-up between data from dry and fresh spinach.

Not only scientists, but also science historians can fail!

Additional info:

National Library of Medicine - Fake! de Terry Hamblin. The most recent overview on which this post is based: Spinach in Blunderland: How the myth that spinach is rich in iron became an urban academic legend.