Spinach and iron: a tale of two myths

Year: 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!

The article by 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.