Imagine this scenario: You’ve just come back from a wonderful week at the beach. While you were away, you got to eat your three favorite foods—pizza, Boardwalk fries, and fried dough. You’ve been back for two days when your mom makes chicken and mashed potatoes but spoils everything by depositing a huge mound of spinach on your plate. Although you have rejected spinach every time she has asked you to eat it, she reminds you that it’s good for you because it contains lots of iron.
I don’t want any parents to be mad at me, but spinach is not good for you because it contains iron. It’s true that spinach is loaded with iron. However, it also contains a chemical called oxalic acid. This acid chemically binds with the iron so most of it can’t be absorbed from your intestinal tract. That means the iron in spinach will go in your mouth one day and exit through your bottom a few days later. You won’t be able to identify it as iron (or spinach, for that matter), but take my word for it that it’s still there.
Before any kids reading this article tell their mom or dad that Dr. Bennett says they don’t need to eat spinach, I have some bad news. Spinach is really good for you; it just has nothing to do with iron. The reason spinach is good for you is because it’s an excellent source of vitamins A and C, fiber and other nutrients that keep you healthy. So your parents are correct in encouraging you to eat spinach, they just do it for the wrong reason.
So where did this iron lore come from regarding spinach? It’s only a guess, but I suspect it has something to do with a cartoon character named Popeye the Sailor who was created in 1929. Popeye was a strong guy with huge forearms, thinning hair, and a corncob pipe. However, when Popeye ate a can of spinach (he did it by squeezing the can and catapulting the spinach into his mouth), he developed superhuman strength. This was presumably because of all the iron that instantly entered his body. Popeye usually needed this extra strength to deal with Bluto, who, as a bad guy caused lots of trouble in the neighborhood.
Although the origin of Popeye’s powers was wrong, he was responsible for at least one amazing feat: getting kids in the past to eat the spinach that was heaped onto their dinner plates. Maybe you really can learn something from television.
First Published in the Washington Post, September 28, 2009