DisprovedChanged2010

Spinach is exceptionally high in iron because of a decimal point error

The old claim turned out to be wrong and was rejected by evidence.

TaughtSpinach has enormous amounts of iron, which is why Popeye eats it. Or, if you had a clever teacher: the iron claim came from a scientist misplacing a decimal point in 1870.

NowBoth versions are wrong. Spinach has a moderate amount of iron, poorly absorbed because of its oxalates. And the famous decimal point story is itself a myth, traced and debunked by Mike Sutton in 2010.

What actually happened

This is the rare entry where the correction your teacher taught you also needs correcting, which is why it is worth including.

Spinach contains roughly 2.7 mg of iron per 100 g, which is respectable for a vegetable but not extraordinary, and the oxalic acid in it binds iron and inhibits absorption, so you get less than the number suggests. The decimal-point story, that a German chemist misplaced a decimal in 1870 and inflated the value tenfold, was popularized by a 1981 article in the British Medical Journal. Mike Sutton went looking for the primary sources in 2010 and found no evidence any such error occurred; the tale appears to have been invented and then repeated by people who enjoyed it, including plenty of scientists writing about the dangers of not checking sources. As for Popeye, his creator said he ate spinach for vitamin A.

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