In his popular column "The God of Small Things", Matt Rudd (Senior Writer for the Sunday Times) writes on page 5 of the Sunday Times Magazine of May 10th 2015):
'Child A announces he no longer has to eat spinach. His teacher told him a 19th-century scientist got the decimal point wrong when they recorded its iron content, inadvertently exaggerating it tenfold.Popeye's superpowers were founded on a myth he claims.
Wait there while I check, I say. Four days later, I have an answer. It is possibly the most convoluted answer in the history of this column, but I'll give you the short version.The decimal point error was first mentioned in an article by Professor Bender in 1971. it has since been used as an example of the importance of accuracy in science.Which is ironic, because there never was a decimal point error in the first place.Dr Mike Sutton of Nottingham Trent University spent many, many weeks getting to the bottom of the myth. The confusion comes from the fact that dried spinach conatains a lot more iron (44.5 mg per 100g) than fresh spinach (2.7mg per 100g). It was this, rather than an errant decimal point, that caused the initial muddle. There was another muddle involving iron oxide.And then Professor Bender came along with his decimal point story, and now we have a myth about a myth.Or a SUPERMYTH, as Dr Sutton calls it.Popeye, by the way, got his superpowers from the beta-carotene in his spinach. Iron had nothing to do with it. To confuse matters much further, spinach still has a relatively high iron content, even without moving any decimal points. But it's still no good. As Sutton points out: "Spinach contains oxalic acid and oxalic acid is an iron blocker."So Child A's teacher was right for the wrong reason. And Child A is now trying to find a reason to avoid broccoli.