Welcome to 35 Milligrams
...And Our First Topic: Fake News & The History of Spinach's Iron Content
Welcome to 35 Milligrams, a substack about:
The importance of checking frameworks, sources, and conclusions.
How there’s nuance to our societal dumpster fires🔥. How, sometimes, there’s even reason to hope✨.
Why call the substack 35 Milligrams? Let’s get into it.
PART I
There’s a false and widely-told story. You can find it everywhere from high-impact medical journals1 to my favorite recipe blog to Reddit to old-school German encyclopedias2:
THE FALSE STORY
35 Milligrams: The number of milligrams of iron people believed were in 100g of fresh spinach from 1840 to 1937. The mistake is why Popeye ate spinach for his super strength. What led to the enduring error? A researcher misplaced a decimal — and, no one bothered to check his work for nearly eight decades. Meanwhile, millions of little kids erroneously followed Popeye’s lead.
There’s even a meme:
Except, like I said, the story is untrue. There are no primary sources to back it. Ironic, for a story about the the importance of careful work.
Where did the story originate? Unclear — but, two historians (with awe-inspiring spinach expertise) have located a German-language version of the story that was published in 19603, which means people have been multilingually repeating it for at least 62 years.
PART II
So if that story is wrong, what is The True History of Discovering Spinach’s Iron Content? Here’s a primary-source backed version:
In the 1800s & 1900s, scientists created and refined processes for determining iron content, testing everything from human blood to horse poop4. They were basically on target with their iron-in-spinach estimates as early as 18725, but kept doggedly checking and publishing their findings anyways6. Eventually, decades of repeated analyses corroborated that — depending on variety and growing conditions — 100g of fresh spinach contains somewhere in the ballpark of 2.7mg of iron7.
And, importantly: the original Popeye was drawn to spinach’s vitamin rather than mineral content8, even if 100g of spinach can have 35mg of iron per 100g — when it’s dried9.
PART III
I gotta tell you, I felt some angst when I learned a story told by some of our snottiest10 fact-checkers about checking work was false. My brain went something like: Fake News even re: spinach? —> Can I trust nothing?? —> PANIC SPIRAL —> Hopelessness.
Then I reminded myself — it was all preventable. Mundanely so: none of the reprints properly checked & cited original sources. That’s why the false story spread. And importantly: the story’s more accurate version is a reminder that humans do great things too. Yeah, The Early History of Spinach has some fake news mixed in, but it’s also the story of a multi-century conversation between scientists refining each other’s work as they moved towards a medically revolutionary set of discoveries — discoveries that helped lead to widespread knowledge of how to avoid vitamin-deficiency diseases like anemia, rickets, beriberi and scurvy. Discoveries that improved or saved millions of lives.
So that’s why this substack is titled 35 Milligrams. The name is a double-reminder to double-check — one of the main things this substack is about. It’s also a reminder that we can conceive of the world as this dumpster-fire place where there’s even Fake Spinach News, or, as a place where alongside that, some people work tirelessly & methodically to save other people’s lives. Because in stories about errors, the larger context may not be all bad — there’s usually nuance (a thing the media fails to report too often).
*
About me: I graduated from NYU’s Journalism school with an MFA last May. Since then, I’ve been on an extended road trip11, constantly being surprised by the disconnect between what’s reported about the places I’ve been visiting versus what they’re like on a daily basis. (More on this in upcoming posts).
Lastly, this substack will be heavily influenced by Effective Altruism. (If you’re not familiar with Effective Altruism, check this out). Functionally, this will mean I’m going to keep asking: (1) If this is our mistake, how do we correct it? (2) How do we correct it in a way that benefits people as much as possible?
Xoxo & Eat your veggies,
Zard
Viz., The BMJ (formerly the British Medical Journal). 2020 Impact Factor: 39.89.
List P.H. (1978). Hagers Handbuch der pharmazeutischen Praxis. Vollständige vierte Neuausgabe. Sechster Band: Chemikalien und Drogen Teil B: R,S. Springer-Verlag, Berlin/Heidelberg, p. 479.
(Via Michael Mielewczik and Janine Moll’s (whopping) 83-page paper: “Spinach in Blunderland: How the myth that spinach is rich in iron became an urban academic legend.”)
In Mielewczik & Moll, p. 103: Schwietzer C.H. (1959/1960). Der eisenreiche Spinat... ? Medizin und Ernährung 1, 130–131.
“Human blood” — An 1895 example from Modern Medicine and Bacteriological Review (see vol. 4, page 150). A measure for dried spinach is included on this page as well.
“Horse poop” — An 1872 example from Comptes Rendus Hebdomadaires des Séances de l'Académie des Sciences 74 (see p. 1355, “Excréments, de cheval”). A measure for fresh spinach (Feuilles d’epinard) is included on the following page.
As recorded by Boussingault (Comptes Rendus Hebdomadaires des Séances de l'Académie des Sciences 74, p. 1356, via Mielewczik & Moll, p. 92)
See linked instances in footnote 4. Direction to additional primary sources can be found in Mielewczik and Moll, especially pp. 66 - 93.
“ballpark of” — See lack of significant change in reported spinach iron content from 1940 (2.5mg, pg. 25) to 2018 (2.7mg). Note: 1940 number must be converted from per pound to per 100g. Additional note: As mentioned above, depending on variety and growing conditions, spinach has a wider iron content range than these numbers suggest. See this 1958 paper by W. Schuphan (German with English summary, via Mielwczik & Moll) or another paper of his from 1972 .
See this interview with E.C. Segar, Popeye’s creator, here (via Evidence & Refutation, which covers this issue in more detail; see Mielewczik & Moll pp. 87 - 90 & 93 - 102 for additional fascinating (at least to me) cultural history on Popeye & his spinach).
I.e., depending on variety. Here’s a study where powdered spinach came in at 40.4mg/100g, and another where it came in at 26.69mg/100g. Here’s an 1895 article (see vol. 4, page 150) — that some cite as (faulty) proof for some versions of the decimal-error story — wherein dried spinach comes in at 35.9mg.
“Snottiest” — E.g., the above-mentioned 1981 BMJ article (titled Fake!) opens with a quote from a 19th-century British poet: “Thou shalt not steal, an empty feat / to cheat. —”
Via a series of writing residencies & house-sits. So far: Arkansas, New Mexico, Colorado, Kansas, Minnesota, Illinois, Massachusetts, Maine. Upcoming: Nebraska, Pennsylvania, New York, A City Near You?
I've been lied to my whole life! Thanks for bringing the hope back re: Popeye & primary sources.
Fun and multi-layered post. There is a sense of awe in hearing an interesting story and then a sense of betrayal in having to wonder whether it is true. Fortunately the ability to research is at our fingertips! A trivial example from my life is a Snapple Fun Fact: A duck's quack doesn't echo, and no one knows why." What? Fascinating. However, also untrue: https://www.theguardian.com/science/2003/sep/08/sciencenews.theguardianlifesupplement. Oh well. But yay research!