Spinach in Blunderland: How the myth that spinach is rich in iron became an urban academic legend

The claim that spinach contains a lot of iron is one of the longest standing myths in science. In recent decades, this early error though has become widely known to the public and several theories were proclaimed, how this misconception was born. The most famous one, known in many varieties and reported in numerous books and scientific journals, is that a simple decimal error occurred. More recently it was claimed that the story of the decimal error is itself a myth and that Popeye against popular belief originally did not eat spinach for its iron content. Unfortunately, not much is known on how urban academic legends and popular misbeliefs in medicine and natural sciences develop and how both facts and errors are popularized. Following an in-depth literature search, the article reports how spinach in the historical and publishing context became popularized as a healthy vegetable rich in iron and how and when this myth was debunked. Briefly, all previous analyses on the origin of the myth only told part of the story. Popularization of spinach as an iron rich vegetable fist occurred in the 1850s. The following propagation of the myth, however, was based on a complex interaction involving scientists, journalists and popular culture, which emphasizes that the impact of science and propagation of ideas is inadequately covered by classic citation links and networks.