The Great Spinach Myth

The facts I use to frame my worldview are steadily becoming ash in the burning light of truth. The process seems interminable; just today, I found out about spinach, and the earth quaked a bit.

Whenever Popeye the Sailor Man needs super strength, he squeezes open a can of spinach, pours it down his throat, and turns into a pipe-smoking dynamo. And it isn’t always Popeye who eats the spinach. In one toon, he forces the spinach down Bluto’s throat so Bluto will work him over, and he’ll get sympathy from that slivery wench, Olive Oyl. And in one cartoon, when a Mae West-like competitor is flirting with Popeye, Olive gets fed up, downs some spinach, and beats the shit out of that hussy. Popeye’s creator, Elzie Crisler Segar, gave his sailor the ability to power up by eating a can of spinach because it was widely known that spinach was a superfood that was packed with iron.

The truth is, spinach has no more iron than any other green vegetable, and the iron it does contain isn’t easily absorbed by our bodies. Spinach’s reputation as a super-source of iron began with a mathematical error. Back in 1870, Erich von Wolf, a German chemist, examined the amount of iron within spinach, among many other green vegetables. In recording his findings, von Wolf accidentally misplaced a decimal point when transcribing data from his notebook, changing the iron content in spinach by an order of magnitude. Once Wolf’s findings were published, spinach’s nutritional value became legendary. This error was eventually corrected in 1937, when someone rechecked the numbers. Spinach actually only 3.5 milligrams of iron in a 100-gram serving, but the accepted fact became 35 milligrams. (The miscalculation was due to a measurement error instead of a slipped decimal, but whatever.) If Wolf’s calculations had been correct each 100-gram serving would be like eating a small piece of a paper clip.

The myth became so widespread that the British Medical Journal published an article outlining the laboratory error in 1981, but spinach’s reputation as a powerful iron supplement has only recently diminished. I’d like to think that’s because of kale instead of nobody watching Popeye anymore.

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